Splendid transitory shelters

  Above is a little page construction built with the intention of quickly explaining the design elements for one specific type of dome.  A physical photograph of this image along with a few other photographs is intended to accompany a disassembled dome kit.  To act as a short explanation and little assembly manual for the dome’s reconstruction.

  Geodesic domes are curious innovations.  The fact that they are strong and can cover a huge volume of space economically, often makes them smartly utilitarian.  They are generally not practical platforms to work with however when considering insulated dwellings like homes or offices.  Materials for modern construction often come in thin, long rectangular shapes or in squarish block forms that resist adaption to curvature.  The chore can be done but details of construction benefiting a personal home like wallboard, cabinetry and trim can become nightmarish for the builder of a proper dome house.  Where domes do shine is in expeditiously enclosing a large volume of internal space while using materials frugally.  As a result most domes are often spacious but thin walled.  Depending upon design and components used they can make good temporary or transportable structures.  Many splendidly large domes have been built in the last six decades but unfortunately, of these many have been torn down.  Some were built as displays for World Fairs or Expos and still survive in a partially changed or re-purposed state.  Other large, pioneering dome examples went neglected and unused until they finally needed to be taken down.  Going back to analyze the biggest or most influential domes led to a re-discovery and investigation of the first great, humongous but temporary greenhouse in history.  The enormous, awe inspiring and refreshingly fanciful Crystal Palace hosted the “Great Exhibition” (the first World’s Fair) almost 170 years ago.

Octagons Don’t Tessellate

  There is a great number of mathematical ways to for the architect or engineer to vary the arrangement of cross-members in the structure of a geodesic dome.  In geometry “geodesic” implies the shortest path between points on a curve.  It takes math to predictably persuade straight building materials to intersect with points on a sphere and still maintain uniformity and structurally rigidity.  You end up using a lot of triangles.  Still, a triangle presents a flat, not curved surface.  In geodesics it is expedient to consider a few regular polyhedrons because they come with polygonal faces and unlike the sphere these 3-dimensional solids are conveniently adaptable to triangulation. 

To expand the plan or size of a sphere or dome it becomes necessary to subdivide polygonal faces into smaller triangles.  This expansion and mapping is called tessellation.  “A tessellation of a flat surface is the tiling of a plane using one or more geometric shapes, called tiles, with no overlaps and no gaps”.  There are only three straightforward “regular tessellations” however, which depend upon three regular polygons (the equilateral triangle, square and hexagon).

  Most geodesic domes constructed will be of Class I type, a much smaller number of Class II and practically none at all of Class III.  It boils down to simplicity and ease of calculating the tessellation.  Only architects, engineers and eggheads like Buckminster Fuller would bother to fiddle with the more complicated constructions.   Buckminster Fuller literally wrote the book on geodesic domes.  He defined criteria and wrote formulae to calculate geodesic dome construction, then sold or licensed this knowledge to architectural firms around the world.  He himself was fond of using the “triacon” (Class II nickname) breakdown for his constructions.  When it comes to the largest domes the triacon offers less confusion for builders than the “alternate” (Class I) breakdowns.  Unlike the alternate, triacon domes or spheres only come in even frequencies but unfortunately these have no great arc equator running down their center-lines.  Importantly the triacon requires fewer different strut lengths; however those lengths may vary a little more.  

* Polygons are 2-dimensional shapes but polyhedrons are 3-dimensional solids.  Both are n-dimensional polytopes.  There is only a handful of “regular” convex polygons but a much larger quantity of irregular, concave and complex polygon types.

* The same holds true for polyhedrons.  You’ve got five regular (even sided, even angled, convex) polyhedrons called “Platonic solids”, thirteen polyhedrons called “Archimedeian solids”, ninety two polyhedrons called “Johnson solids” and then a bewildering number of other possible irregular, stellated / concave polyhedrons that can be considered.  Then for every polyhedron there is a reciprocal or “alter ego” so to speak called a dual.



*  Within mathematics a whole branch of geometry called “polyhedral combinatorics” can find an absurd number of ways to twist and contort the polyhedra, and it has the notation to describe them all.

  This following picture shows only Class I dome examples and begins with the basic icosahedron which has a frequency of “1” and who’s “Schläfli symbol notation” is {3,5 +}1,0.  The alternate breakdown or tessellation continues to be used as the frequency is increased.

* This picture and the 1’st image of this post were concerned with constructing a portable dome from 3/4” EMT (Electrical Metallic Tubing).  In America this galvanized conduit is sold in 10 foot lengths.  That size and length cut in half (5′) is almost strong enough to support the weight of a normal person climbing around upon the dome, without one of its cross-members bending.  For economy of material the dome heights and diameters in this picture are consequent to the longest possible strut (pipe) length being no longer than 5 feet.

* From the picture: the 5/8ths version of a 3v dome is practically as tall as the 4v version that conveniently does have an equator.  However when jumping to 4v the number of different strut lengths doubles, which can significantly complicate the chore of assembly.  It should take at least 2 people assisting one another to assemble a 3v 5/8ths version and at least 3 people to move it because the completed construction would be ungainly and would weigh about 360 lbs. when made out of pipe.

* For the 5v and 6v versions a ludicrous 9 separate strut lengths are required.  Concentration will be required to assemble such a puzzle correctly.  Additionally, working 23 ft. above ground will necessitate the use of scaffolding, a crane or mechanical hoist.


Distinguished dome examples



In 1967 the World’s Fair or “Expo 67” was held in Montreal, Quebec, Canada.  A group of architects and designers known as the Cambridge Seven Associates, Inc. were tasked with the responsibility for creating and furnishing the United States pavilion for that exhibition.  For the structure they decided upon a large geodesic dome.  Fuller & Sadao Inc. (Buckminster Fuller and Shoji Sadao) were hired to plan the sophisticated shell.


The dome’s geometry has been described as being a combination of a 32- frequency regular triacon (Class II, method 3) and a 16-frequency truncatable alternate (Class I, method 3).  Below; at the top left of the modified photo the only, easily discernible pentagon in the image is tinted red.

Originally this historic dome was enclosed by transparent acrylic panels. This <7:24 minute video> by Cambridge Seven eloquently documents many details about the historic pavilion.  The dome caught fire in 1976, which destroyed the acrylic but didn’t melt the steel frame.  ‘Environment Canada’ acquired the structure in 1990 and turned it into what is now a museum called the Montreal Biosphere.



_ Shareable images of Kaiser Aluminum domes are rare on the Internet.  Above is an unexceptional photograph of an aluminum dome, which functions as the community center for Borger,Texas.   Around 1956 the famous industrialist Henry J. Kaiser and Buckminster Fuller joined together to start a company that manufactured and sold aluminum domes like this one.  Several examples still exist – here and there around the globe.  Even today lightweight, economical and corrosion resistant aluminum seems to be the most practical material with which to enclose a large dome.  Erection of these particular domes sixty years ago was very quick because the polygon shaped prefabricated metal panels just bolted together.  This surviving example in Borger, Texas has served as community center for more than half a century.  An identical or kindred example also in Texas, survives as a popular and continuously used theater near Fort Worth.  Two more of these Kaiser aluminum domes (not pictured) long lasted as concert auditoriums.  The Virginia Beach dome was erected in 1957 and taken down in 1994.  The Hawaiian Hilton dome in Honolulu was also erected in 1957, was aluminum, acted as a auditorium with good acoustics and was taken down only in 1999 to make space for a newer building.


_ Better copyrighted pictures exist but above are some allowable public domain images of what was at one time – the largest “clear span” building in the world.  It was designed by Thomas C. Howard of Synergetics, Inc. and owned by the Union Tank Car Company.  The dome was built in 1958 near Baton Rouge, Louisiana.  It measured 384 feet in diameter and was 128 feet (> twelve stories) high.  When the real estate was purchased by another company the dome went abandoned and neglected for a couple of decades.  Unfortunately it vanished in 2008.


_ In 1964 New York City opened the only Registered (Universal) world exposition to be held without BIE (Bureau International des Expositions) approval.  “Expo 1964” ran for 18 months; three times longer than normal.  A dome large enough to seat 2,100 people was designed by Thomas C. Howard of Synergetics, Inc. and built as a pavilion.  This building later housed the Winston Churchill exhibit in 1965.  After that the dome was dismantled, moved and the frame (only) re-erected to serve as an aviary for the Queen’s Zoo (NYC).  While the dome is not particularly tall, it is a generous 175 feet in diameter.  These few “free to use and share” licensed images above don’t quite do the structure justice.


_ Between 1971 and 1973 the United States Naval Construction Battalion (the Seabees) erected a dome at the Amundsen-Scott South Pole Station.  The NSF (U.S. National Science Foundation) only expected to get 10 to 15 years of service life from the structure but it lasted until 2009 before it was taken down.  There were vent holes in the crown of the dome to bleed off excess heat.  Temperatures above freezing would have allowed the structure and its contents to sink deep into the snow. At least the dome blocked the fierce Antarctic winds.  Designed by Temcor Inc. the dome is said to have been based upon a Class-II frequency 14 triacon breakdown.

_ Temcor was absorbed by CST Industries Inc. somewhere around 2009.  The company creates the largest domes in existence and is probably the biggest dome manufacturer and installer in the world.  As of 2009 they’d already installed something like 7,500 aluminum domes or dome shaped roofs, in 72 different countries.   In Long Beach, California a huge Temcor dome sits close to the Queen Mary.  That dome was initially built to house the famously large “Spruce Goose”.


The Crystal Palace

_ Quickly assembled buildings providing vast open interiors, did not begin with geodesic domes.  The grandest example of such a building was created six or seven generations ago.   It took only sixteen months from start to finish to design, manufacture and erect the modular Crystal Palace, on site.  It would sit upon some of the most valuable ground in the world.  The humongous and airy glass building was then filled with eight miles of tables, for fourteen thousand promoters which displayed more than one hundred thousand different exhibits.  The Great Exhibition opened May 1, 1851.  It was a grand success.  And profitable.  In the five months before the exhibition ended more than six million paying customers would walk through the Palace’s doors. Then this biggest building in the world at the time was itself sold off,  removed from Hyde Park and reassembled in another location of London.

_ Many great and energetic minds joined to make this well engineered spectacle a possibility.   More credit belongs to one person perhaps than to anyone else – Prince Albert, Consort to Queen Victoria.   Once his notion caught traction with private investors, then the government pitched in and a Royal Commission was appointed to mount the Exhibition.   Meanwhile a separate Building Committee comprised of the most respected engineers and architects in the Empire was formed – to oversee the design and construction of the exhibition building.  Among their demands were that the building be temporary, cheap to build and fast to erect.  After entertaining planning submissions from all over Europe in 1850, they received and discarded some 245 submissions before choosing one.  It was partially by luck that Joseph Paxton’s plan was picked.  Iron and glass “hot houses” (conservatories or greenhouses) were new and fashionable novelties during this Victorian period.  Paxton was certainly not the only adventurist architect that built them.


Monkey Closets in the “Retiring Rooms”

_ To “Spend a Penny” was to become a long lived euphemism for going to the toilet.  It all started with the Great Exhibition and the exciting, first ever public toilets.  It cost one penny to rent a Monkey Closet.  Back then a penny was worth considerably more than today; remember Britain had the lower half penny and farthing (¼ penny) denominations of coin.  But a penny here bought a cleaned toilet seat, a small towel and a shoe shine.  By the end of the Exhibition no less than 827,280 adventurers availed themselves of this luxury.

_ In its initial configuration the conservatory resembled a huge rectangular flat topped box, having only one lofted transept at its center.  Still this open building was more than one-third of a mile long and more than 2.5 American football fields wide.  In places it was built over and around full sized trees.  Its structural components consisted of ten million square feet of heavy flat glass plus unknown tons of cast iron columns, trusses and trellis girders and unknown tons of wood planking for the second story floor. 

_ The railroad and steam locomotives that brought this material in were new ideas themselves.  Portland cement was new and economical flat glass was new.  It was the diminutive size of the architectural glass itself that ultimately determined the shape and size of the whole building.  The largest plate glass that could be efficiently made at the time measured 10 inches by 49 inches and today it would be referred to as cast plate glass.  Production cost was substantially lessened and construction was simplified because Paxton’s plan was drawn around using millions of these identical panes of glass.  Other parts were mass produced also and some served multiple functions.  The posts and girders came straight from the foundry and could be bolted together to form free standing modules in no time.

_ The building only stayed in Hyde Park for five months but it was to exist for eighty four more years in another location across town.  There, it probably outlived everyone that ventured through it in 1851.  Once it was moved to a more prepared location the Crystal Palace (a nickname coined by a newspaperman) would acquire two more transepts, additional wings and running fountains both inside and out.

_ The photo above is dated 1854.  Photography was very much in its infancy at that time.  Daguerreotypes had been around since 1839 but the collodion process wasn’t announced or published until March 1851.  This image (by Philip Henry Delamotte) could be from an Ambrotype (a positive image on glass).  The American Civil War photographer Mathew Brady studied his craft in Europe and actually displayed some of his portraits at the Great Exhibition in 1851.


_ There were two new water towers built at the new location, only the one at the South end of the Palace is seen here, above left.  Impressive in their own right from an engineering perspective, at 280ft tall the towers were not quite as tall as the Statue of Liberty and its large pedestal combined.  A painting of a Royal Navy ceremony-dated 1917 is the center thumbnail.  The third picture is of a naval gun, dated between 1920 – 1924.

_ These last photographs are presented as thumbnails mainly because they are bandwidth hoggish and would slow down the web-page otherwise.  The first photo below shows the Central and North transepts, the North water tower and North wing – which normally held new agricultural and industrial implements on display.  This excellent picture must have been made before 1866 because that’s the year that the North transept caught fire and burned up.  In 1871 the world’s largest saltwater aquarium took its place.  In the next photograph the North transept is clearly missing.  This aerial photo had to have been taken sometime before 1936 because that is the year when the whole Crystal Palace was destroyed by fire.  The two water towers survived the fire but were deliberately destroyed shortly later in WWII to deny German bomber pilots a visual fix from such an established landmark.

_ Over its eight decade long lifespan the Crystal Palace attracted and hosted a broad assortment of eccentric and eclectic attractions. Year after year it hosted performances, concerts and public festivals.  In this doctored photograph below, taken somewhere between 1887 and 1889, some blocks of about 100 people are colored in. This particular photo is said to show a Handel Festival taking place at one end of the big central transept. The Grand Orchestra of about 4,000 musicians surrounded the organ.  The Great Organ in the back of the photo had 4,500 pipes, some obviously out of sight.  There was only enough room left to seat 4,000 spectators in the audience.  One wonders what these orchestras sounded like.  Did they produce magnificent awe-inspiring sounds or did this many musicians produce a very loud cacophony?



Bake, Boil & Brew

_ This installment discusses some really simple, primitive forms baking which can be done over an open fire.  Then uncomplicated soups and stews become the next subject matter.   If one has a pot then soups and stews were a very sensible way to prepare food over an open fire and were historically more commonplace in household kitchens than they are today too.  Finally, a discussion of fermented beverages.   With sugar becoming more available and affordable in the 16th century, exciting new beverages called “small beers” would come about.   Consumed by the billions daily worldwide, several of today’s artificially carbonated soft drinks are a direct evolution of yesteryear’s small beers.

Ash Cakes

 _ One can bake a primitive but tasty bread in a fire without using pot or pan.  A soldier in the Continental Army 200 years ago or a legionary in the Roman army 2,000 years ago might have been given only raw flour as part of their daily ration and both were expected to know how to cook it.  Mixing flour with water and cooking it as a wet gruel was one option.  If on the march and having little or no time or utensils to bake a more proper bread, then turning flour into ash cakes was usually more favorable than eating gruel.  One simply added a small amount water to the flour and mixed it up.  The mixture was then rolled around in the hands and kneaded a little before being dropped onto a flat hot rock, a piece of tree bark or simply dropped into hot but not flaming ashes at the side of the fire.  The cook tended it carefully, tilting it or flipping it as necessary.  The ashes which are thoroughly sterile don’t really cling to the bread later and can be blown off easily.  Another way that the Romans occasionally cooked the same flour ration, was to roll the dough into a little rope and then swirl that around a stick.  The stick was stuck into the ground and leaned over the fire like a diagonal spit.

*  About 75% of a Roman legionaries diet was issued as a ration of grain.  Had they the time, legionaries usually prepared their breads in advance of a march.  For short term consumption (say within 4 or 5 days) they might have baked leavened breads or unleavened type breads akin to pita (Gk).  For a longer lasting bread resistant to spoilage they might have over-baked something similar to what we now recognize as a “hardtack” or “sea biscuit”.  A contuberniam (the smallest organized unit of soldiers in the Roman Army / about 8 men) slept in the same leather tent (usually of goatskin & waterproof), traveled with their own portable stone gristmill (a quern or quern-stone) and baked in a small portable 2-piece ceramic oven called a clibanus.  When a Roman army marched or moved to a new location they carried a lot of food and equipment with them.  Each legionnaire was loaded down with personal gear while non-combatant servants led pack animals or wagons loaded with the contuberniam’s heavier items in a supply train which followed the legion.

*  When on the march Roman legionaries carried a small personal utensil known as a  patera” to drink and eat from.  A patera along with a spoon probably composed the first military issued mess kit.  A larger bronze pot or kettle was probably shared by the whole contuberniam.


Corn or maize was a New World plant and the rest of the world was not introduced to the crop until the 16th century.  Corn is generally identified as being either flint or dent type.  Flint corn has kernel tops that are round, and dent corn kernels are marked with a dent or dimple.  Popcorn and sweet corn are flints while yellow corn hybrids grown for cattle feed or ethanol production are examples of dent corn.  Hominy is”nixtamalized” by soaking it in an alkali solution like slaked lime or lye.  This process reduces the presence of mycotoxins and releases more proteins and niacin for digestion.  Corn has no gluten and so without the help of another flour that contains gluten, it will not bind together or rise like a normal bread.  Hoe cakes, corn dodgers, corn pone, johnny cakes and hush puppies may have occasionally been made with only cornmeal in the past but most modern recipes call for a little wheat flour to be added.

* “Parched corn”: When corn kernels mature they get very hard; so hard they become almost impossible to eat.  So hard that it is very inconvenient to crack with a mortar & pestleThe Native American “Indians” that cultivated corn also devised the stone “metate” to crush the suborn kernels. Soldiers or travelers carrying these stubborn seeds learned that they could roast them in a pan over the fire. A few of the kernels might pop.  This process called “parching” the corn tenderized it, simplifying the task of grinding and then cooking the kernels.

*  It is possible to boil a small amount of water over a fire without any special utensil.  Water can be placed over a fire in broad leaves or in a broad strip of tree bark.  Because of the absorption of water, the fire is prevented from burning through.

_ “Hardtack”, “sea bread” or “sea biscuit” is an old, primitive form of bread that was valued for its robustness and resistance to spoilage.  Before a voyage, a ship was provisioned with many barrels full of sea biscuits.  A water tight cooperage was not required because the commodity contained within them was not liquid.  Therefore weevils might eventually find their way into some of these cheaper kegs (cask or “barricas” in Portuguese & Spanish).

The regulation sea biscuit was well standardized by the British Navy before the 17th century.  It took about 4 sea biscuits to make a pound; part of a sailors standard daily ration was 1 pound of bread.  But it was a salty, wood hard, unpleasant bread that usually required a soaking in something before it could be eaten.  Whereas normal baked breads would quickly mold and plain flour would go rancid or become bug infested on a long sea trip; the salty, hard, twice or triple baked sea biscuit if stored properly, could last several years before being consumed.  Sea cooks when in need of a flour could still crush up sea biscuits with a hammer.  “Hardtack” became a popularized term for the same bread about the time of the American Civil War.  A traveler, explorer, soldier or pioneer could tie a bag of these to his pack-horse and not worry about them crumbling apart after months worth of physical abuse.

The recipe for hardtack or sea biscuits is super simple, the detail is in the baking.  Whole wheat flour, salt and a little water are the only ingredients.  Only enough water to make a stiff dough is necessary.  The dough is kneaded a little bit, then separated into balls which are squashed flat to the size of a crumpet or big cookie.  It’s usually perforated a little on the top to let gas escape while it cooks.  There is no set salt ratio in most recipes but the amount usually seems excessive.  Salt has been mankind’s first and most effective chemical food preservative. The baking needs to be done slowly, dehydration is the main goal.  In the archaic ovens of yesteryear this might have taken all day.  Between Latin and Old French languages the word “biscuit” itself means – “twice cooked”.  Usually two days then in an earth oven to get that hardtack dry.

*  Earth ovens, pizza ovens and hornos work by absorbing and trapping heat.  A hot fire is built within them and is allowed to burn down before the embers and ashes are swept out.  The goods to be baked are inserted and the opening is then closed off to seal in the heat.

Fluffier breads

_   Now is not the time to get bogged down with long explanations of quick-breads, leavening and sourdough.  These topics are briefly discussed in an older post (Yeast & Fermentation) anyway.   Quick-breads are relatively new and rely upon a chemical reaction from ingredients (soda and acid) that are mixed into the flour.   When moisture is added then gas bubbles are formed and expand the dough, making it “rise” artificially.   Sourdough is ancient; it is a bread made from leavening (yeast culture) which might have been passed down from mother to daughter throughout the ages.   Before yeasts were identified under a microscope, people did not know what device in leaven caused breads rise.  Now we know that enzymes convert starches to sugars and that yeast digest sugars to create ethanol and carbon dioxide gas.   When wet, the sticky gluten in flour traps the gas from fermentation, allowing the dough to inflate.   Sourdough then implies a bread made from a wild yeast culture and perhaps some beneficial lactobacillus bacteria as well, but also the word sourdough implies a practice wherein a portion of each new sponge (dough) is withdrawn and saved to be used as the “starter” leaven for future use.  Pioneers, expeditions and army chuck-wagon cooks brought their sourdough starter (leavening) with them; because doing so was easier and much faster than attempting to create a new yeast culture from scratch.  Over time the more durable cast iron Dutch oven would eventually replace the ceramic clibanus as the ideal utensil to bake with over an open fire


_  Whenever there was a fire in the average home of yesteryear, pots or kettles of hot water and soup were constantly maintained close by the fireplaces or stoves.  The soup pot was in a constant state of cooking and was seldom ever completely emptied.  Any vegetables, grains or small scraps of meat and more water would be tossed into the pot whenever the occasion arose.   In the cold of winter this practice was thermodynamic-ally accommodating because the liquid in the pots collected or banked thermal energy and slowly released it back into the house if or when the fire died down.  Importantly though, cooking in a pot conserves the oils, fats and nutrients from food that would otherwise drip off into the flames when grilling for example.

_  Copper and earthenware pots and cookware have been used at the hearth for eons.  By the 17th century however the state of the art and the most desirable cookware to be found in Europe was cast from brass.  The Dutch reputedly produced the best cast cookware.  At the onset of the 18th century an Englishman visited a foundry in the Netherlands, learned their sand casting technique and then began to duplicate the casting of brass cookware back in England.  Copper, bronze and brass are expensive metals though so he began to experiment with cheaper cast iron.  After much trial and error he eventually became successful in casting iron cookware from sand molds and patented the process in 1707.  The next two centuries saw a boom in the worldwide demand for this cast iron cookware; especially for the robust lidded pots meant to sit right down in the fire, called “Dutch ovens” (by everyone but the Dutch).

*  China, India, Japan and Korea had a long history of cooking in iron vessels but these were not produced in large numbers.

*   Cast iron cookware was tough and versatile and became almost indispensable to the daily life of a household.  When conditioned and maintained correctly cast iron skillets have better and more durable “non-stick” surfaces than the newest pans with Teflon or ceramic coatings.  Large cast iron kettles or cauldrons were used over fires outside to boil water for laundry, to scald chickens or pigs and to render tallow for making soap.  Cooks might have used a single Dutch oven to boil, bake, fry, stew, or roast.  When writing a will, mothers sometimes divided their beloved cast iron cookery up between favorite children.  During the 1804-1806 Lewis & Clark journey across the continent it is noteworthy that the 31 man expedition carried not one but two heavy Dutch ovens on the trip.  One of the ovens fell out of a packsaddle, rolled down a hill and shattered though.  Still the metal fragments made useful gifts and implements of barter to Indian tribes met along the way.

_  Soup can be made from most anything.  Desperate or starving people have even been known to boil their leather belts & shoes, which is not as crazy as it seems.  The major component of leather is a fibrous protein called collagenGelatin which is a foodstuff made by the tons commercially, is made from animal skins, ligaments, and bones.  Gelatin finds its way into many processed foods, including ice creams, marshmallows and candies. 

  A talented cook often begins a soup with a stock or broth that might already be available and on hand.  A stock or broth might serve a cook in many ways besides being used in just a soup though.  A stock is started whenever there are some useful bones or meat scraps laying around the kitchen, that might otherwise go to waste.  Any lidded pot will do or a “crock pot” but dedicated modern stove-top stockpots are made of stainless steel and the most useful range between 1 and 3 gallons in volume (4-12 liters).

Making a stock

_  Perhaps a day or two after a holiday dinner there is a goose, chicken or turkey carcass in your refrigerator.  The prime sections of meat might have been sliced off or pulled away but what is left is skin and bones and small, less desirable pieces of meat.  A good cook would gather up all that scrap up and toss it in a stock pot, add water to submerge the carcass and then set the stove to a low heat, simmering it for several hours or for the rest of the day.  That experienced cook would also undoubtedly add some onion, carrots and celery, and perhaps add some bay leaves, parsley and thyme.

_  Stock is usually not boiled because that creates a murky liquid.  Fresh meat or bone scraps create just as good or better stock than previously cooked ones will, however smoke and barbecue flavors from cooked meat carry over especially well.  Other vegetables or vegetable peelings and spices can be used.  A toss of wine can compliment the final taste.  After it has simmered for a long time most of the flavors and nutrients will have been drawn into the liquid.  The stock is then poured or strained into another container and the solids are discarded.  After being chilled, a layer of gelatin will usually form at the top of the stock or completely through the stock in a well executed example.  In a refrigerator the broth might enjoy a grace period of several idle days before it really needs to be used.

_  Pork or mutton stocks are rarely made because of the fatty oils and yellowish coloring they produce.  Poultry and beef seem to be the most popular stocks but ham and fish stocks are also encountered.

Examples of stock based soups:

-* Borscht is a Russian soup made from meat stock and beets.

-* Consommé is a very clear soup, deviating little from regular meat stock except that it has been clarified by using egg whites to remove fat and sediment.

-* French onion soup is made from stock and browned onions and was frequently used as a concession to the poor because of some obscure French law that required all restaurants to offer something appreciably affordable on their menus.

-* Bisque originally referred to a thick cream soup made from the broth of shellfish like crab, shrimp or lobster.  In an authentic bisque, the shells are ground to a fine paste and added to thicken the soup.  Today it is common to see cream-based soups that do not contain seafood.  Thanks to the modern blender or food processor we have added pureed mushroom, squash, tomato and red pepper to our “bisque” repertoire.

-* Vichyssoise sounds French but it might have been American in origin. It contains chicken stock, leeks, onions, potatoes and cream.

_ “Condiment soup” is not entirely a joke because it can have practical applications and be useful survival advice of a sort.  Winter life in an alpine ski village can be otherworldly.  Whether in American or in the finest European ski resorts, civilization is precariously perched upon slick, cold and inhospitable slopes of deep snow.  Skiing or snowboarding is foremost a sport for the affluent.  At the base lodges or midway lodges further up the mountain, cafes and small restaurants do exist but their prices for food and beverages are truly exorbitant.  There is a class of young but poor skiers who manage to play at these resorts because they preform menial work there.  They might drive snowplows, do room service, operate gondolas or chairlifts, bar-tend or preform ski patrol duty. These workers are lucky enough just to get lift tickets or to find places to sleep at night on their minimal pay.  They aren’t going to be able to afford a sandwich or hot drink at the ski lodge when prices are inflated five or six times what they should be.  When one of these working class skiers stumbles in from the cold; their hands and gloves cold and wet, their nose and cheeks beet red and shaking from hypothermia, then they can either purchase amenities at outrageous prices or turn to the ski bum’s condiment soup.

_ The whole plan depends upon disposable cups, refills of free hot water and a condiment bar.  Usually individual packets of seasonings like mayonnaise, tomato ketchup, mustard, pickle relish, coffee creamer, salt, pepper and sugar are to be found at the condiment bars.  Sometimes crackers, diced onions and tomatoes, shredded cheese and more exotic flavorings like tartar sauce, chili sauce or Chinese hot mustard can be found also.  The skillful ski bum then with cup of hot water in hand, takes note of the available condiments and crafts his hot cocktail accordingly.

Sugar and Carbon Dioxide

_ Coke® is but one flavor or one brand of soft-drink and yet for every day that goes by almost 1.2 billion servings of Coke alone are consumed around the world.  The average American drinks an estimated and unhealthy 44.9 gallons (170 L) of “sodas” per year. Aside from flavor and cool serving temperatures the primary elements making soft-drinks so addictive are sugar content and the carbon dioxide fizz. 

Soft-drinks are mildly acidic because when carbon dioxide gas is added, it dissolves into solution and forms carbonic acid.  The carbon dioxide dissolved in the soft drink might come from byproduct gas collected and compressed from fermentation at a brewery or could be captured and purified waste gas from factories or power plants that are required to trap the greenhouse gas.  Most colas (like Coke) have food grade phosphoric acid added as well to add “bite” to the taste.  Today in a manner similar to soft-drinks, almost all commercial beers too are deliberately injected with pressurized CO2, before sealing the can, keg or bottle.

In earlier times though CO2 gas was created within a closed bottle by adding a little priming sugar or malt before capping it shut.  The results are less uniform when using this “secondary fermentation” procedure; beers can turn out flat if not enough gas is made or can burst the bottle if too much gas is made.  Champagne predominantly uses only the secondary fermentation method to create gas within the bottle.  Since bubbles are the hallmark of Champagne and other sparkling wines, more gas than usual is dissolved within these beverages, so bottles must be made extra strong to withstand the extra pressure.

Kombucha culture, kefir grains and ginger beer plant are examples of SCOBY s (Symbiotic Cultures of Bacteria and Yeast).  These are gelatinous or semi solid cultures of a mixture of microorganisms.  Much like sourdough starter, a portion is separated and used to begin a new fermented drink but the starting culture is maintained independently.  Drinks made from cultures like these are often associated with the newly coined term “probiotics”.   Supposedly these live probiotic microorganism improve gut flora, help the immune system and provide other health benefits.  Many uniquely flavored drinks can be created from using cultures like these, and all are fermented, slightly alcoholic and lightly effervescent. 

The Kombucha beverage is a fermented sweet tea probably originating from Russia or China, and prepared by many today for its supposed health benefits.  Milk kefir originated in the Russian/Caucasus/Turkish area and might have a sour taste similar to thin yogurt.  Beet kvass is a traditional Russian beverage started from a milk or water kefir culture, where beets and scraps of wheat or rye bread and a dash of salt are thrown together to ferment.  There are apple, berry and raisin versions of kvass too.

Ginger beer plant” is an older (1700s British) name for a symbiotic culture that might have been used to create a batch of “ginger ale” or a host of other flavored-fermented beverages depending upon the herbs, leaves, barks or roots used.  “Small beers” that created such a taste sensation four centuries ago may or may not have depended upon these gelatinous cultures for a start.  There are plenty of yeasts and beneficial bacteria on the herbs and roots used or floating around in the atmosphere.  What really permitted the small beer and resulting soda-pop phenomenon to occur in the first place– was the introduction of sugar as a plentiful food source.

* Sugarcane is just a huge tropical grass that originally grew in humid Southeast Asia.  For the longest time refined sugar was considered a rare and expensive spice by Europeans.  Sugarcane wouldn’t grow as a crop in Europe because of the harsh climate.  On his second voyage Christopher Columbus brought the first sugarcane roots to the Caribbean to test the plant for cultivation.  Soon sugarcane plantations would sprout up on several islands.  With too many islands in the Caribbean for Spain to control, French, Dutch and British traders and privateers would establish separate communities there too a bit later.  By the 1620’s processed sugar and molasses from sugarcane would become a significant cash crop for these latecomers as well.

* Sugar from sugar beets was never realized until a German chemist noticed that the beet roots contained sucrose. The first refined beet sugar commodity appeared around 1802.

* HFCS (High Fructose Corn Syrup) is an unnatural, biochemically different sweeter that must be processed differently by the body.

Small Beers

_ Back say two or three centuries ago everyone in the family with visitors and servants included would drink the household small beer if it was available and it usually was.   Children drank it for breakfast like they would cold orange juice or refrigerated milk today.  The alcohol content was usually minuscule, probably seldom reaching 2.5 ABV.   At its heart a small beer was a weak infusion of some root, bark, spice or fruit boiled in water, to which sugar and yeast were added and allowed to ferment for a few days.

Today we think of ginger ale and root beer as being flavored soft drinks but they actually started out as small beers.   Today the term “ginger beer” is used to differentiate the alcoholic version from the soft drink version “ginger ale”.  Either a batch of ginger ale, ginger beer or root beer can be begun with the help of a “ginger beer plant” SCOBY mentioned earlier.  But these beverages can also be started with something simpler called a “ginger bug” instead.  A ginger bug is similar to the more dedicated ginger beer plant SCOBY, but is a younger, liquid / not semi-solid colony of microorganisms.  To create a ginger bug one simply slices some fresh unpeeled ginger root into a jar of sugar water and leaves it exposed to the air on the kitchen counter top.   Every day a little more ginger and sugar might be added.  In a week or so wild yeast and bacteria will be caught and bubbles of carbon dioxide will be seen rising in the jar.  Ready to use now, a portion might be saved away as a sourdough starter would be while the other portion is used: added to a sweetened tea like infusion or a sweetened decoction of boiled roots or something.   If ginger ale is the target beverage then the ginger bug itself would probably provide insufficient ginger flavor.  In this case one usually creates a separate strong, sweet ginger tea and then adds the ginger bug starter to that.

_  Long before the Pilgrims landed on Plymouth Rock the local Indians were boiling up sassafras roots which are sweet, to make a kind of tea.  Along with the growing accessibility of sugar, it did not take long before European colonists joined “old world” knowledge of brewing techniques, with new indigenous flavors to create “root beer”.   Many different root beer recipes existed and employed an assortment of ingredients.  The central or most common ingredient in most variants of root beer was the sweet root of the sassafras tree.  Depending upon recipe some other typical flavorings in root beer were sarsaparilla, ginger, licorice, birch, juniper, hops, wintergreen leaf and dandelion root.  Almost none of the flavors in today’s commercial soft drinks are natural any more, but are instead artificial flavors and frequently synthesized from petrochemicals

* In the 1960s the FDA outlawed the use of sassafras in commercially made root beer.   It seems that some laboratory study identified the key polyphenol in sassafras called safrole and determined that it could cause cancer in lab rats if they were fed massive quantities for a long time.   Sassafras root probably contains no more safrole than basil, nutmeg or cinnamon but these items obviously were not taken off the market.

* Sarsaparilla comes from a tropical greenbrier type climbing vine.   It is not native N. America but is to Central and South America, and the Caribbean Islands.   The local Carib Indians were drinking sarsaparilla health tonic type tea before the Spanish got there.   Extract from the vine has been valued for centuries as medicine for treating illness like eczema, contact dermatitis, psoriasis, syphilis and arthritis.  It is easy to imagine that this new medicinal commodity shared the same boat ride along with sugar, to all points of the compass.    More history:

* Birch beer originated in the 18th century as small beer flavored with the boiled extract of bark, twigs, sap and roots of the black birch tree.

* Europeans found Native Americans around Quebec drinking a spruce tea of a type, early in the 16th century.  Later in the 1700s several enlightened people were concocting “Spruce Beers”.  The tender buds at the tips of branches or sprouting new trees were sour, complimented the taste of sugar water and were eventually determined to prevent scurvy (because of the “vitamin C” content).  Both Benjamin Franklin and the intrepid Captain James Cook recorded recipes for making spruce beer but the volumes they used or proposed were very large.  Cook’s Spruce beer  / Univ of Wellington

* Beer on Board in the Age of Sail /blog post


_ Not all soft drinks sprouted from the sugar fermentation / small beer route though.   Sparkling mineral water from a spring must have been mankind’s first encounter with carbonated water.   If that water is still considered safe and is bottled for sale, then it might contain minerals like potassium, sodium or magnesium.   By the tail end of the 1700s chemist were toying with the notion of making artificial sparkling water.   Someone discovered that they could artificially dissolve carbon dioxide into water by first creating the gas by dripping sulfuric acid onto chalk and then bubbling the gas up through water.   In English this product might have just been called “seltzer water”.   Fruit juices and perhaps ice were mixed in for a taste sensation.   By 1819 a patent was issued for the first “soda fountain” which actually used a pump and spigot to dispense the carbonated water into a flavored syrup.   By the 1830s new methods of production allowed for the cheaper carbonation of seltzer water and soda fountains were springing up all over the place.   Aside from mineral water and seltzer water are a couple of other clear sparkling beverages known as Club Soda and Tonic Water.

_ Club Soda is predominately seltzer water, with sodium bicarbonate, sodium citrate, disodium phosphate and perhaps some sodium chloride thrown in.   Tonic Water came about though because a long time ago some British soldiers deplored the awful taste of their malaria medicine and added soda and sugar (and later gin) to the water that the alkaloid powder was dissolved in.   About four centuries ago a Jesuit priest had brought quinine back to Europe from the wilds of Bolivia and Peru.   Quinine is very bitter and comes from the bark of Cinchona or Quina trees.   The alkaloid interferes with the reproduction of malaria-causing protozoa and is still used to combat malaria today.   In the past quinine was in higher demand around the world and the Bolivians and Peruvians became greedy over export of the tree bark.   The Dutch smuggled seeds out of South America and began growing Quina trees in Java.   Just before WWII, plantations in Java were producing 97% of the world’s quinine.   The Axis takeover of the Netherlands, Indonesia and the Philippines during the war caused a severe quinine shortage for everyone else in the world that suffered from malaria.  Used mainly in the famous British “Gin and Tonic” cocktail, the soft drinks called “Tonic Water” today are much more docile tasting than they once were because they contain less quinine hydrochloride.   Carbonated water has also replaced the sodium bicarbonate component.






Isometric Camouflage

Camouflage” was not an existing word back in 1890 when the Darwinist-zoologists Sir Edward Poulton  wrote his book ‘The Colours of Animals’.  It was not yet a proper word even later in 1909 when Abbott Handerson Thayer  wrote his controversial book entitled ‘Concealing-Coloration in the Animal Kingdom’.   With a vocabulary more limited than now, Thayer’s work began by explaining how an otherwise, utterly conspicuous bird like the male peacock could veritably vanish inside a forest.

The Italian verb “camuffare” means to hide or disguise.  The French verb “camoufler” similarly means to conceal or cover up – as a theater actor might apply makeup right before a performance.  The French word “camouflet” is used as a noun perhaps to depict a snub or an insult or it might describe a crater in the ground caused by an underground explosive.  Camouflet might be the smoke blown into someone’s face as a practical joke.  The word “camouflage” is newer; possibly dreamed-up during the trench warfare of WWI, by some French infantryman as he lay freshly covered over with dirt excavated by nearby artillery bombardment.  In the last century the definition of this new word camouflage, has swelled to include many types of deception to the eye or subliminal trick to the brain.

  The concept of camouflage is very old.  Mother Nature itself is resplendent with convincing examples of camouflage.  Both below the water or above, most predators and prey alike participate in the masquerade of visual deception.  Even plants play the game.  Some plants deliberately attract while others can effectively repel pollinators or herbivores with their looks alone.  Thousands of years ago aboriginal hunters might have been the first humans to use camouflage, if they wore animal skins as a disguise to hunt game.  From time immemorial camouflage has proven to be a very advantageous survival tool for a great many living things.  It will continue to be so tomorrow.  Mankind today being no exception, has need to hide from himself.

Why does it work?

Not all “camo” is good camouflage.   Some military camo is really poor.  At best even the majority of nature’s camouflage schemes are specialized or static and so will succeed only for a limited set of circumstances.  Some fish, chameleons, squids and octopuses though are luckily equipped with the ability to dynamically change their disguises.   Chromatophores present in their skins empower this magical ability.

Color is certainly not the only important component of successful camouflage.  With humans in fact, color-blind individuals have been actively sought for as airborne artillery spotters or as snipers by the military, specifically because they are not distracted or fooled by colors.  These people with unusual red-green color receptors in their eyes may be better equipped to see certain underlying contrast that outline the shape of a threat.  Though color is still important to the average eye, any eye can still be led astray by other, more subtle mechanisms.  Mechanisms, some of which to be explained shortly.

Sophisticated modern optics and hypersensitive sensors are being exploited on the battlefields now.  Effective military camouflage schemes today and in the future will need to work for a broader electromagnetic spectrum, which means masquerading even in non-visible light.

Contemporary with the Napoleonic Wars, military uniforms were usually bright and colorful.  The British and Danish armies were fond of red coats, the Spanish, Austrian and Saxon armies favored bright white or light gray, the Poles, Prussians and Napoleonic French wore dark blue colors and the Russians wore green.  The arrival of more accurate firearms with longer reach due to the rifling of barrels, changed that.  By the time of WWI most progressive armies had switched to low visibility clothing and soldiers were now hiding behind objects for protection rather than standing starkly out in the open.

To be sure there were some isolated incidences of soldiers wearing camouflage well before WWI.  For example Rogers Rangers who participated in the French Indian Wars, wore uniforms that were dyed green.  The French led Wabanaki Confederacy natives that they opposed, wore deerskin if anything and were harder to see.  On the other side of the planet and around 1846 a British officer of an Indian Army regiment had his whole troop go down to the river and rub mud into their new white cotton uniforms.  Later still and on yet another continent the first “gillie suits” for snipers were used by Scottish soldiers fighting in the Boer Wars of South Africa, a decade before WWI.

camouflage netting


<Expandable Thumbnails follow>  the “tiger-stripe” camouflage worn during the Vietnam War provided good concealment in the jungle.  The French introduced the pattern.  The American uniform versions were great at first but due to faulty dyeing processes – would fade badly after a laundry wash.

The coat below would work as camouflage in a room full of steaks.

Below is an example of bad camouflage.  It’s a three color patten of shapes with a tiny scale.   The uniforms must look like homogeneous pea soup from a distance.

Any notion that one camouflage can be appropriate in many different environments is a preposterous proposition.  Nonetheless this silly one-for-all camo notion continues to be funded, researched and tested.  The reason is that an organization like the Army, or any other branch of military service, works as a team.  Basic military psychology dictates that members of a team should look and dress alike.  Each of the individual services wants a new, modern, high tech look.  Outfitting hundreds of thousands of soldiers with four or five sets of new uniforms and accouterments soon gets to be very expensive.  In 2004 the US Department of Defense spent $5 billion to outfit the Army with a new pattern of camouflage uniforms.  Then the Army decided they didn’t like it.

The computerized, digitized, scientifically analyzed UCP (Universal Camouflage Pattern) adopted by the US Army a few years ago is a prime example of a camouflage flop.  Some fundamental design considerations were ignored.  The omission of black was a stupid decision.  The pale, cement colored, pixelated UPC could only look natural for someone standing inside a rock quarry.  The Army might have been wiser to stick with solid, century old khaki, olive drab or feldgrau colors.

There is nothing wrong with pixelated patterns but don’t buy into the gimmick that computers can make camo planning decisions.  UPC was a three color camo scheme where the contrast was too insubstantial.  Additionally the scale of the contrasting regions was too small within UCP.  Most camouflaged uniforms though, mistakenly use too small a scale of pattern.  There is little need to deceive the enemy’s eye at close up range, but greater need to fool it at rifle or battlefield range (300 meters).  The chunks of contrasting colors need to be much larger to affect an observer from distance.

There is still great room for improvement in the world of military camouflage and it is a realm where the psychologist with discretionary artistic skills can still innovate.  No doubt there are as yet, still undiscovered and inventive ways to lead the eyes astray.


It is from nature that mankind gets his camouflage ideas.  In nature you find both plants and animals exploiting cryptic coloration to hide or mimicry to impersonate something else.  Some of the flowering plants (especially some orchids) practice a highly developed mimicry.   The intent is usually to attract bees, wasp or flies to assist in pollination.

< * Of the many borrowed photographs to follow: first, they have been declared to be of public domain; second, wherever possible an effort has been made to embed attribution and source metadata into each JPEG photo – should it be examined or downloaded. >

As if the imitation of a stick isn’t good enough, the phasmid below also carries its tail higher than his head, offering a less crucial first target to a predator.

The phenomenon of countershading went unappreciated until about a century ago when the naturalist and artist named Abbott Thayer (who painted the peacock mentioned earlier) first identified this mechanism.  Thayer noticed that many animals have a dark upper body but a lighter underbelly.  He reasoned, that these animals when illuminated by sunlight from above have their overall appearance flatted or dulled rather than accentuated.

The illustration on the left is from Thayer’s original book, right side from Wikipedia.

   Disruptive coloration and alternating shapes in camouflage attempt to visually scramble the contour or outline of a subject.  A net thrown over an artillery piece interrupts or breaks up the outline of the cannon.  A disruptive eye mask or eyestripes on many an animal helps disguise its vulnerable, usually dark and distinctive eyes.  Shapes or patterns that are distractive enough will lead the eye away from the edges or outline of a form.  The coloration in these disruptive patterns are often strongly and abruptly contrasted.  Symmetry is carefully avoided, because animal brains are wired to notice spatial correspondence.


Notice the semi-circles created by contrasting light – against dark bands on this viper below.  Notice how the markings run perpendicular or counter-intuitive to the body’s axis.  These markings disrupt quick interpretation of the viper’s contour by offering a more attention getting alternative for the viewer’s eye.

eye stripe

Below, notice the direction of the disruptive stripes on the legs.

Cubism and Dazzle camouflage

A noteworthy art movement beginning at the dawn of the 20th century was known as “Cubism”.  With cubism the art does not necessarily try to make a 2-dimensional canvas look 3D, but it does attempt to depict a subject from multiple viewpoints.  In cubism the elements of a subject are broken up and are then reassembled in an abstract form.  (*The following examples of cubism are declared public domain by virtue of their old age – which here exceeds 75 years).

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The stark designs put on ships beginning with WWI are known as “dazzle camouflage” and have roots or kindred elements with cubist art. The purpose of dazzle camouflage was not to conceal a ship, but to foil an enemy’s attempts to accurately calculate its range, heading or speed using optical observations.  The original “dazzle” as credited to British artist Norman Wilkinson was very blunt, to serve a purpose.  Later the term would be applied to every type of concealing paint job put on a ship, whether that resembled cubism or not.

Below the dazzle pattern helps foil a potential torpedo’s firing solution by misdirection of the ship’s actual heading.

* In the 1860’s the state of the art for aiming a large cannon was to look down the barrel and fire point blank.  In following decades, longer shots at sea were accomplished by guessing a range and then elevating the barrel beforehand while waiting for the sea swell to bring the target into the aim of pre-adjusted iron sights.  Concurrent with the Spanish American War, ships began to be equipped with optical rangefinders invented by Admiral Bradley Allen Fiske.  His stadimeter was a handheld device that looked similar to a sextant and which would later be incorporated into almost all submarine periscopes.  Versions of his coincidence rangefinder that worked by triangulation and trigonometry would quickly find their way into all warships and land based artillery units.  Radar (RAdio Detection And Ranging) was still in its infancy at the beginning of WW2.  In a few short years radars were incorporated or retrofitted into the latest British and American fire control systems aboard ships.  At first radar just augmented either the huge (long baseline) coincidence or stereoscopic type optical rangefinders.


  In WWII the paint jobs on ships were looking very different, but the name dazzle still stuck. The famous German battlecruiser Scharnhorst shown above right mimics a smaller, less threatening ship from a distance.

 In the split picture below an unknown warship hides against the bank or cliff side.  The battleship Tirpitz (sister ship to the Bismarck) spent much of the war hiding in such a way.  The cruiser on the right side has a bow wave painted on its front, making it appear to be traveling much faster than it might be.

The catchall “dazzle camouflage” phrase is still being applied to some new warships and face paints today.

The once very popular Argus C3 camera used a stereoscopic rangefinder to focus its lens. Cameras with SLR (Single Lens Reflex) mechanisms would eventually overtake the rangefinder sort, a possible advantage being superior performance at close up distances.

Yet another version of dazzle is CV Dazzle, created by artist Adam Harvey.  CV stands for Computer Vision and his concern is resisting the quickly growing surveillance state that tracks people’s moment with digital cameras and facial recognition software.  The anonymous people behind this intrusive surveillance, be they law enforcement or employees of a private company – just take what imagery they want without asking.  Facial recognition software has grown quite sophisticated recently.  Analyzing how these algorithms work so that they might be countered or thwarted might be good subject mater for a future post.

* Now that some established examples of camouflage have been shown 
and the topic outlined a bit; it comes time to introduce some 
ideas that might improve new camouflage schemes for the future...

Op Art

Op Art (or Optical Art) uses optical illusions.  Op Art is abstract, employing perhaps only black and white lines to create an impression of movement or to conceal another image.  Some optical illusions can occur without man’s help, when our physical environment can distort what we perceive, perhaps by bending light.  Atmospheric conditions might be responsible for mirages, for the moon to seem bigger than it should, for far away mountains to appear closer than they really are or for a straight stick to appear bent when you see part of it dip below the surface of water.  Another category of distortions, ambiguities and paradoxes of perception can be caused by physiological activity in the retina of one’s eye.  Afterimages that might linger in one’s vision after he looks away from a high contrast image is an example of physiological optical illusion which is caused by photochemical activity in the retina.  In the so-called  “Hermann grid  illusion” (from German physiologist, Ludimar Hermann /1870) a person probably senses black dots where they don’t exist – because the separate light and dark receptors of the eye are scrambled and are competing with each other for attention.

The most common types of optical illusions may involve neither biology of the eye nor altered perceptions caused by natural environmental factors.  Instead, because of the way the human brain is connected and conditioned it is capable of making very quick assumptions and then of sometimes jumping to false conclusions.


Impossible objects” are two-dimensional figures that can be subconsciously interpreted as three-dimensional objects.  Impossible objects are not physically rational but they can be drawn.  The ‘Penrose stairs’ and the ‘Impossible Triangle’ shown above were both originally thought up and published by a British psychiatrist and his physicist son in the 1950’s.  The Dutch graphics artist M.C. Escher would later incorporate the impossible staircase into some of his work.

Geometrical illusions would appear to distort reality when they actually don’t.  Many are named for the physiologist or psychiatrist who originally created them.  Some simple examples would include the Müller-Lyer illusion, the Hering illusion, the Zollner illusion,  and the shifted-chessboard illusion originated by German-American psychologist Hugo Münsterberg.  Completely different but still a “geometrical illusion” is the  checkerboard illusion (and here is a dynamic HTML version) .

Ambiguous illusions can offer more than one valid perception or interpretation.  The “Necker cube” is an old ambiguous illusion that dates back to 1832 and a Swiss crystallographer (someone who studies atomic arrangements in crystalline solids) by that name.  Around 1915 the Danish psychologist Edgar Rubin created the first ambiguous or reversing two-dimensional form to be called – a “Rubin’s vase”.  Four such vases are shown below.

Hybrid illusions can be perceived in more than one way, depending upon viewing distance.  These illusions can be created by superimposing blurred elements of different photographs over one another.  The technique was originally proposed by Aude Olivia and Philippe Schyns in 1994.  One image dominates up close but another takes over as you step back.




Shadowing plays a very important role in “peripheral drift illusions“.  Reversing the shadowing reverses the rotation of drift.  Strong contrast, blinking, eye movement, peripheral vision and the brain’s perceptual processing contribute to the illusionary sensation of motion.  The almost famous “rotating snakes” image below was copyrighted in 2003 by Akiyoshi KITAOKA, Professor, Department of Psychology, Ritsumeikan University, Kyoto, Japan.  The professor has drawn many other illusions which are also displayed on his website.

Working with similar tricks, the false spiral or twisted cord illusion does not appear to move.  In 1908 a British psychologist named Sir James Fraser drew the first false spiral, where the arcs are actually a series of concentric circles.

Pinna’s Intertwining Illusion is a derivative of the twisted cord illusion.

* Only a few methods of optical illusion have been shown here.
 These toy with either physiologic or psychological mechanism.
 One can better now hopefully perceive, how optical illusions
 when incorporated into camouflage patterns – might help
 enhance the disruptive affect of those patterns.


Holography, Lenticular lenses, Agamographs & Stereoscopy

Real holograms reproduce very realistic 3D renderings of objects but both the recording and the viewing require laser light.  The hologram itself is a surface profile of the light field surrounding an object.  There are some techniques available to mimic the 3D effect of holograms though.  Lenticular lenses for instance are glass or plastic lenses, textured with ridges or rows of bumps.  In lenticular printing, two or more images are interlaced together on a paper or substrate and then bonded to the base of the lenticular lens.  Either the result looks 3-dimensional or a separate image altogether appears when the viewer observes from a different angle.

Working on a similar principle as the lenticular lens are “Agamographs” which are named after a noteworthy artist named Yaacov Agam.  While Agam made sculptures or artworks from various materials, anyone can create a facsimile of a 3D image by folding paper in a special way and painting segments of different stereo images on alternating folds.

Stereoscopy is stereoscopic imagining and there are a few different ways to do that.   Stereoscopes are the contraptions that you look into to see a three dimensional image with realistic depth.  The left and right eye are segregated to see slightly different vantage points of the same object and then the brain’s visual cortex combines the binocular disparities to produce depth perception.   A typical stereograph consist of two photographs that were taken simultaneously by a special camera that uses two lenses and two sets of film.  A “stereogram” once meant the same as stereograph.  Now however stereogram is synonymous with “autostereogram” – which is a single 2D image that can be perceived as a 3D image, without the help of a stereoscope or use of two images.

Autostereograms depend upon the difference or binocular disparity between two good eyes to create a 3D impression.   Computer software is used to map depth coordinates obtained from one form – to the surface of another image.  Some of the pixels of the surface image are shifted according to the depth of the hidden form.  Most autostereograms are intended to be viewed by means of “wall-eyed convergence”, which means the viewer stares through the graphic, not crossing his eyes.  Visual neuroscientist Christopher W. Tyler with the help of a computer programmer, created the first autostereograms in 1979.  However a simpler form of random-dot stereogram technique was being discussed 60 years before that.

Projection and Perspective

  It could be mentioned that for artwork or mechanical drafting, there are many ways to project a three-dimensional object onto a two-dimensional surface.  First, a 3D projection will have lines of sight or projection lines that are either in perspective or are in parallel.   Perspective in a drawing is where lines converge or skew towards one or more vanishing points.  The lines of parallel projections however, don’t converge into the distance.  Oblique projections slant or slope and have no perpendicular nor parallel relationship with any line or plane surface.  Axonometric projections have lines of sight that are perpendicular to the plane of projection.  Axonometric drawings also have edges or axes that are measured to scale but any curves or diagonals will be optically distorted.
  When architects or engineers want to whip out a quick sketch of a building or object they might resort to a simple parallel/axonometric drawing known as an isometric projection.  The angles in isometric projections are all multiples of 30 degrees.  A draftsman that still knows how to hold a pencil might use a drawing aid known as a 30-60-90 set square, or might sketch on isometric graph paper where the lines are already marked.  Less often used, dimetric and trimetric projections look similar to isometric axonometric projections but use different angles.

Infrared light

In previous decades the thermal imaging night vision equipment that soldiers might have used, worked within the invisible long wavelength infrared (LWIR) or mid wavelength infrared (MWIR) spectrum. These worked by reading the heat emitted by the object itself. Today’s higher generation / newer tech night vision equipment though, uses the ambient IR sent from very distant stars.

These newer night optics predominately rely upon lower wavelengths and higher frequencies; either from the short wavelength infrared (SWIR) or near infrared (NIR) spectrums. These optics produce high resolution images by reading absorption characteristics returned from a target.

Different substances have different IR absorption characteristics. There are many materials that absorb IR, less that reflect IR, some that are transparent to IR and even some materials under development for the influence they might have on infrared light. Some textiles, nets and miscellaneous surfaces used by the military, already dabble with coatings intended to affect visibility in the IR spectrum.



There has been some real research done and authentic videos showing how invisibility cloaks could work, but also some false videos about invisibility cloaks – using Hollywood style “blue screen” techniques and video editing software.  The authentic research has a long way to go before the technology could ever be used in a camouflaged suit however.

The invisibility videos that are honest, must still be carefully staged.  The demonstration or illusion if you prefer requires a computer, a video camera, a retro-reflective material, a projector, an iris diaphragm and a beam splitter.  Typically a person stands behind a blanket of special fabric and you think you can see through him; because a camera is filming the scene behind him as a projector puts that same image on the blanket.  The smaller details are complicated.

Metamaterials that can bend light are under development too.  These also have a long way to go before becoming physically practical as a means of concealment.

stencil project

In the slideshow that follows a prospective pattern using some isometric angles and a few circles, was quickly colored in using four colors.   Ostensibly for painting something small like a toolbox.  The original intention was to study how difficult it would be to design a pattern which would comfortably replicate itself over a larger area, once its stencils were moved adjacently up or down or sideways.  Not an elementary task.  Considering that the base-coat of an item will already be of one color, only 3 stencils would need to be cut out with an X-Acto knife.  This is just a disposable example.  The components are a bit too numerous and sometimes too close together to leave behind a sturdy stencil once the holes are cut out.  After re-reading this post the last slide in the series features a little “disruptive shadowing”, added as an afterthought.

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Pigments, Paints & Dyes

Today volumes and varieties of premixed paints are easily purchased in stores, but this has not always been the case.  Our predecessors just a generation or two prior had to make their own paints, whether intended for a house or barn, or for art.  Right up into the 1930’s or 40’s in construction, paint was made on the job-site and the contractors had to apprentice for many years before becoming competent and considered qualified to make quality paint.  The accomplished fine art painters or masters of yesteryear were akin to alchemist and their materials were varied.  Simultaneously however, many unskilled but ambitious artist may have watched their creations crack, change color or literally slide away from the canvas.  While premixed oil paints were being sold in little squeezable tubes by the 1860s, the knowledgeable and adept artist still depended upon the ability to grind his own pigments and mix his own paints.  With a little know-how it is actually easy to make a decent paint, in most any color.  Cro-Magnon cavemen mixed metallic oxides with tallow or clay to make paints that are still clinging to some stone walls today after thirty six thousand years have passed.  Our repertoire of pigments and binders has grown since then.  An attempt will be made here to organize and explain some basic binders, pigments and dyestuff.

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* Visiting cave paintings briefly;

   The elements are in a constant state of flux. The erosion and the degradation caused by mother nature is very rough. Any artistic medium must be robust to survive even a decade.  These cave paintings and sculptures of the long since past have only survived because they were sheltered and protected.  Most of the cave art in Europe created during the last ice age has probably been destroyed as a result of successive human activity.  Continued human habitation within a cave would lead to increased smoke and soot. Excessive carbon dioxide from both fire and human breathing might have encouraged detrimental lichen and mold growth upon the cave’s interior. Those caves today that still possess clear aurignacian or gravettian period cave art, do so because they became sealed off somehow from the outside atmosphere. The early humans that painted the pictures seldom if ever lived in those particular caves where cave art has survived. Multiple painters over a wide span of time created the artworks in these caves. Three of the most prominent caves in Europe still possessing pristine parietal paintings were just recently (analogous to their age) re-discovered. The Cave of Altamira in the north of Spain was found in 1879. The Lascaux Cave in the southern half of France was found shortly after the German occupation of France in 1940.  The Chauvet-Pont-d’Arc Cave of south France was re-discovered only in 1994.  These have all been sealed off again, as protection from outside atmosphere and from contamination by human tourism. Pablo Picasso who in 1948 visited the Lascaux cave before it was closed to the public, praised the prehistoric art; stating that man had learned nothing new since then.

The principle colored pigments used in the Lascaux cave for instance were the iron oxides or hydroxides known as hematite, goethite and ocher. Black pigments were provided by magnesium oxide and charcoal.  European cave paintings, engravings and sculptures are grouped together or classified as “Franco-Cantabrian” art because of their geographical concentration inland, both east and south of the Bay of Biscay.


It usually takes only two or three items to create a paint; a binder, a pigment and a filler.  Any particular paint is classified by its type of binder that in turn is reduce-able by a solvent.  Binders hold pigments and fillers together and onto surfaces.  Pigments can come from plants or animals, from dirt or rock minerals or they can be chemically synthetic.  Fillers if present might influence the opacity of a paint but mainly are added to expand or extend a paint’s bulk and coverage without affecting its color.  When comparing an oil, a tempera or an acrylic version of paint; these might all share the same exact pigment but differ only in having incompatible binders.  The chemical sophistication of modern day automobile paint mixtures are perhaps no more confusing, nor are more complex than some of the mixtures used on the pallets of the late Renaissance painters.  A host of toxic materials like arsenic, chromium, lead, radium and uranium were once commonly used in paints because they were effective.  Commercial house, furniture and spray paints today are usually less convoluted than the compounds once found on an artist’s pallet.  There, one may have found rarefied distillations of tree sap, rabbit skin glue, raw egg yoke, crushed up bug juice or perhaps even pulverized mummy remains.


The binder dries to form a film that then determines the texture, flexibility and permanency of paint.  Children like to taste things.  Naturally they put things in their mouths as they explore the world about them.  Many effective, once popular binders (or pigments as well) have been removed from commercial paints for this very reason.  Child safe paints, most of which can be produced at home anyway would include binders composed of glutinous grain starch (from rice, rye, wheat flours, etc), soap, shampoo, gum Arabic, shaving cream, gelatin, clay, honey and maple syrup.  Example paint binders not fit for consumption would include things like tallow, linseed and tung oil, shellac, raw egg yoke, beeswax, water glass (sodium silicate), acrylic, epoxy resin, alkyd resins and nitrocellulose lacquer.  A solvent is usually needed to thin out paint, to clean equipment or to clean up spills.  Some example solvents would include “the universal solvent” (water), alcohol, ether, essential oils, turpentines from plants, mineral spirits from coal tar, naphthas like benzene, toluene and xylene from petroleum.

   Casein is an ancient paint binder and glue, one regularly used by the Egyptians.  Made from milk protein, casein makes an excellent woodworking glue and it can also create a fine water soluble paint that dries quickly.  Used in ancient “tempera” (or preferably “distemper”) paints, casein paint was actually the favored medium for many modern illustrators right up into the 1960s. Then acrylic paints generally replaced casein bound paints in popularity, because casein paint if unused would tend to spoil after a few days.  For centuries moisture resistant casein glue has been used in laminated wood and furniture.  Casein immersed in formaldehyde created one of the earliest synthetic plastics.  Casein glue is milk protein (itself called “casein” which comprises about 3% of milk) dissolved in an aqueous alkaline solvent.  Making a simple casein glue or binder involves little more than causing milk to curdle by introducing vinegar under mild heat, pressing out the excess whey and then neutralizing the acid with an alkali solution (like baking soda and water) with a little more heat.  Non-fat milk makes better glue than whole milk would because fat molecules prevent the casein from properly polymerizing.  Low-fat cottage cheese is already converted to curds so it works faster than milk.  The type of alkali used, substantially influences the properties of the final glue or binder.  Alkali s like borax (sodium tetraborate), ammonium carbonate (originally acquired by the destructive distillation of red deer antlers or “hartshorn”), potash (potassium carbonate) and lime ( either “quicklime” (calcium oxide) or “slacked lime” (calcium hydroxide)) have all been used to engineer casein glue and paint binders.  Quick lime or slacked lime works well for casein paints which need to be alkali resistant for applications like stuccoed walls or fences.  The “fresco” below was done by a Minoan painter sometime between 1600 and 1500 BC.

Fresco / https://commons.wikimedia.org/wiki/File:Fresco_of_a_fisherman,_Akrotiri,_Greece.jpg

Minoan Bronze Age fresco

When you mix cellulose with lye and heat it you get a mild but useful glue known as methyl cellulose.  Methyl cellulose can be used as a lubricant, an emulsifier, gel, as an additive for food, shampoo and toothpaste, as an additive to mortars and gypsum related construction materials and as a binder for medications, wallpaper paste, liquid paints and in dry pastel crayons.

  Hide glue and the gelatin we often eat in some processed foods are both made from an animal protein known as collagen.  It is soluble only in water and therefore is insoluble in oils, alcohol or other organic solvents.  Hide glue is typically made from animal hides and perhaps hooves, tendons and bones (bones are cured in a lime slurry for a couple months before being boiled in water and then reduced).  The hide liquor can be further processed by drying and then by crushing it into chips, flakes or powders that are intended to be re-constituted with water at a later date.  A little heat is necessary so that the re-hydrated binder can be converted from a gel to a liquid before it is applied.  It does not store well in wet form and unused portions will mold.  Hide glue is the preferred glue used for stringed instruments like violins and cellos.  The wood in these delicate instruments is under stress and will expand or contract according to humidity, temperature or external pressure.  Hide glue when dry is appropriately flexible and weaker that the wood it is bonded to.  If a violin is stressed to the point of breakage then the glue bond should break before the wood does. Ideally the instrument can be easily fixed.  This is a handy feature considering that some 300 year old Guarneri del Jesu and Antonio Stradivari instruments can fetch more than $16 million at auction.

Usually animal skin glue is used to prepare, pre-coat or seal a ‘support’.  In the world of ‘fine art’ a support is the substructure of a painting – like wood, paper or stretched canvas.  The ground is the foundation, that first layer of primer painted upon the support.  The size is necessary only for fabric supports and it is painted on above the ground to plug up and and seal the canvas from the penetration of oils. Linen and cotton will prematurely rot without a size layer.  Many sizes have been used but rabbit skin glue was the most conventional ‘size’ used for oil painting and was supposed to be a bit stronger, more elastic and slower to gel than other hide glues.  If used for a ‘size’ then rabbit skin glue was usually mixed with gypsum, marble dust and titanium dioxide to create traditional white ‘gesso‘ sizing. Since climatic changes in temperature and humidity can cause old oil paintings to crack, poly vinyl acetate has become the preferred binder in contemporary ‘gesso’ or ‘size’ for fabric supports.  Fish glue or “isinglass” (made from air bladders, boiled skins and fish bones) was used by the ancient Egyptians and was later prevalent in the parchment manuscripts illustrated and gilded by medieval monks.  Fish glue was one of the more successful fixatives used in pastels, where pulverized pigment, white chalk and binder were commonly rolled up into a cylinder before they were dried.  Today isinglass is still useful as a “fining agent” for the clarification of some wines and beers.

* Tempera, Distemper, Encaustic and Fresco painting:

   Casein and hide glue have been used since antiquity to bind up and apply pulverized pigments.  The term “tempera” has often been used to casually imply several mediums (like egg, honey, plant gums milk casein and hide glue) though.  To most artist today “tempera” implies a technique employing only the egg yoke medium, and they might use the new term “distemper” to differentiate and encompass the other binders used in a similar way.  Tempera painting is very old and robust and was very common before “oil paints” became popular in the 15th century.  Some examples of tempera still exist, which were painted almost two thousand years ago.  Egg tempera dries very quickly so usually a bit of wine, vinegar or water is added to extend its period of workability.  Also about 2,000 years old, “encaustic” painting is a technique where pigments are added to melted beeswax.  Metal tools, special brushes and heat are used to spread the pigmented wax around before it solidifies.  “Fresco” (meaning fresh) is a technique where pigment is applied onto wet plaster.  The hue is drawn into and becomes part of the wet plaster itself after it is applied to ceilings, walls or murals. “Fresco-secco” on the other hand describes painting upon dried plaster.  The famous ceiling of the Sistine Chapel taken as a whole, is an enormous fresco painting done by Michelangelo about 500 years ago.

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  Silicate mineral paints are made from mineral pigments and soluble glass as the binder. “Water glass” (sodium or potassium silicate, liquid glass or Keimfarben) is made by melting silicon dioxide (silica / quartz sand) and soda ash (sodium carbonate) together.  The result is an exterior masonry paint binder or indoor product for mural painting, that is far more resistant to cold and damp and ultraviolet light than traditional lime fresco is.  Keimfarben was popular for a while as a 19th century variation of fresco, and remains useful today as a coverage for concrete and masonry walls.  Other uses for sodium silicate include its use as a paper glue in the manufacture of cardboard, as a tool for water treatment, as a fixative for reactive dyes, as a binder for refractory mixes and as a major component of dry-powder laundry and dishwasher detergents.


Some of the most important binders of all time are the so-called “drying oils”. These are the foundation of oil paints. When exposed to oxygen these particular oils have the property of polymerizing into the hard films we associate with dry finished, cured paint.  Linseed oil and tung oil are the most significant examples in this category but there are others less frequently used like poppy oil, soybean oil, castor oil, candelnut oil and so on.

  Linseed oil is squeezed from the seeds of the flax plant.  Flax seeds are edible and the fibers from the plant are probably the longest ones to be found in the textile industry.  Linen is the fabric made from flax fibers and both ancient Babylonians and ancient Egyptians cultivated the plant.  Raw linseed oil is edible but it does not dry or oxidize very quickly.  Therefore a quicker to dry “boiled linseed” was realized by experimentation.  In the 19th century additives like lead acetate and zinc sulfate were introduced to raw linseed oil and then heated, to improve the drying performance of the oil.  Today the heavy metal driers (perhaps cobalt & manganese salts) of boiled linseed oil may have changed to ones safer to handle, but boiled linseed is still not safe to eat.

  Tung oil (or Chinese wood oil) usage reaches way back before the Song Dynasty in China. The oil is squeezed from the nuts of a poisonous tree. This oil was or still is used for waterproofing wooden ships & paper umbrellas and for providing light when used as a lamp oil.  Modern day granite and marble counter-tops can be waterproofed and made stain resistant by thinned coats of tung oil.  Tung trees were once imported to the southeastern U.S. and planted as commercial crops.  Since that time the prolific and toxic trees have been classified as unwanted and invasive plants in states like Florida and Mississippi.  There have been incidents where school children on field trips have been poisoned after mistaking tung nuts for chestnuts.

Both linseed and tung oils make superior wood finishes that penetrate deep and rejuvenate cellulose.  Tung oil which is more expensive, may or may not be preferable in some situations because it is less likely to darken wood or to yellow.  Tung oil will eventually harden or polymerize by itself but boiled linseed preforms much faster – making linseed by far the most common drying oil employed in oil paints.

* Linoleum is a superior type of non slip floor covering made with linseed oil, which was invented around 1855 and became very popular by the beginning of the 20th century.  Being more flexible than ceramic tile, it could be applied to wooden floors and not crack under stress.  The thick inlaid linoleum floors were extremely durable but eventually thinner, printed pattern linoleum tile was manufactured.  Still this thinner linoleum flooring should be preferable to the cheap polyvinyl chloride (PVC) floor covering so popular today.  Simple enough to make at a remote construction site, linoleum fabrication usually began with a burlap or canvas backing.  The obligatory ingredients for linoleum tile were fine sawdust (or wood flour) linseed oil and some color pigment. Occasionally pine rosin and calcium carbonate (crushed limestone / as an extender) was thrown into the mix.  In fact, calcium carbonate (occasionally called whiting) is often used to extend or to fill in many types of paint, plastics and thermosetting resins.


Gums, resins, turpentines and essential oils come from plants and whether mixed to together or used separately they still have been used as paint binders for hundreds or even thousands of years. “Gums” for example result from “gummosis” which is a condition of sap flowing from a wound or disease in a bush or tree.  Gums are colloidal (a mixture in solution that does not settle) and are soluble in water while simultaneously being insoluble in alcohol or ether.  Resins may occur either alone or alongside gums and essential oils but they are conversely – insoluble in water but are dissolved by alcohol and ether.  Then there is a large group of harder resins called “copals”.   Amber which is a petrified tree sap, falls into this category.  Oleoresins are solutions of resin or wax mixed with essential oils and fatty oils.  Turpentine is an oleoresin collected and distilled usually from pine tree sap.  Balsams are like oleoresins but are generally more aromatic and occur naturally.  Essential oils are the fragrant, volatile compounds from plants, usually extracted by distillation.

Confusingly gum arabic and Arabic gum are two very separate but famous and important tree saps.  The natural gum and polysaccharide “gum arabic” comes from the hardened sap of select acacia trees.  “Arabic gum” (or mastic) on the other hand is resin collected from a totally unrelated dioecious shrub of the Pistacia (pistachio) family.  Both resins were known in antiquity, both were used in foods, as medicines, as paint binders and both still share great value as precious commodities.  A major portion of the world’s supply of gum Arabic comes from Sudan while most mastic comes from a small island, farther northwards from the equator.

Gum arabic is composed of saccharides and glycoproteins which give it the utility of a glue and paint binder and make it edible by humans.  Thousands of years ago the Egyptian Pharaohs were being mummified with the help of gum Arabic.  It is the same useful glue used on the back of a postage stamp, which is licked before sticking to an envelope.  It is used in cosmetics, shoe polish, candies and chocolates, to treat upset stomachs or to stop both diarrhea or constipation.  Gum arabic is indispensable in traditional lithography, paper and textile printing, where it controls viscosity in inks or repels ink from background areas on the plate of an offset press.  “A dab of gum arabic makes newspaper ink more cohesive and permanent”.   In medicine, gum arabic is used as an emulsifier to keep ingredients from separating or as a demulcent to temporarily defend the mouth, lips, tongue, eyes or nose from irritation.  It is used in glazes and paints, particularly in watercolors where it binds pigments to paper.  Gum arabic literally holds the multi-billion dollar soft drink industry together.  Without its ability as an emulsifier, the sugar in a ‘soda pop’ would crystallize and settle to the bottom of its container.  The economic importance of this tree sap has been influential enough to sway national policy.

Mastic or ‘Arabic gum’ was once worth its weight in gold.  It has long been collected from the sap of the Pistacia lentiscus shrub which is mostly cultivated on the Greek island of Chios.  Once dried in the sun the resin could be used as a chewing gum.  The English word “masticate” stems from an original Greek verb for chewing.  Mastic has antibacterial and anti-fungal properties that may counteract gingivitis and tooth decay.  Mastic also contains antioxidants and has traditional been used in medicine.  Just like the gum collected from Sudanese acacia trees, mastic is used to make cosmetics, incense, perfumes, soaps and lotions.  Transparent varnishes made with mastic were once very useful in preserving photographic negatives.


In the English language the term “resin” it too vague.  A resin usually denotes a highly viscous organic residue and a residue that often solidifies after contact with air.  Within the plant a resin might control water loss or act as an antiseptic. “Oleoresin” is a broad term for compounds collectively containing resins and oils (like turpentine).  At least two different types of oil are distinguished: fatty oils (containing fatty acid chains, lipids, triglycerides and such) and essential oils – which contain volatile aromatic compounds.  A “balsam” isn’t distilled but is an aromatic oleoresin that occurs naturally.  “Copal” was originally a semi hard tree sap used as incense by the natives of Central America, now it is a catchall phrase for similar resins that make good hard elastic varnishes.  Copals can be dissolved by oleoresins, by essential oils or by acetone; but to do so sometimes requires the application of heat.  Amber is a rock, a fossilized resin and the hardest copal.  Rosin is a resin usually collected from pine trees.  Rosin is what is left over after turpentine has been cooked and separated from pine tree sap.  After destructive distillation the leftover solid is ground up into a powder.   Rosin is used in adhesives, soaps, soldering flux, optical lens polishing compound, etching plates in printmaking and in oil paints and tempera emulsions of fine art.  It sees employment as a traction or friction enhancer used by rock climbers, weight lifters, bull riders, gymnast, ballet dancers, violinist and cellist alike.   There are many other plant gums or resins used as binders or glazes in paints.

Also found or even predominant in modern paints are thermosetting and thermoplastic resins.  A “thermoset” or thermosetting polymer is at first soft or liquid, malleable or mold-able before it is irreversibly cured or “set”.  Once hardened, heat cannot be used to change a thermoset’s shape.  Examples of thermosetting resin include Bakelite, epoxy resin, vulcanized rubber, polyurethanes and polyester resin and silicone (the rubber like adhesive and sealant, not the chemical element silicon).  Thermoplastic resins on the other hand are often formed to shapes by injection molding or extrusion molding, but once cooled are still quite modifiable in shape by the reintroduction of heat.  Example thermoplastics include acrylic, nylon, Teflon, polycarbonate, polyethylene, polypropylene, polyvinyl chloride and polystyrene resins.

*  Distillation is used to divide mixtures into separate components.  Destructive distillation (pyrolysis) uses heat to drive off valuable liquids and “volatiles” from organic material.  The organic material’s original form is lost, its molecules cracked, reduced or rearranged into new compounds.  Charcoal, methanol, tar and turpentine are gained by the destructive distillation of wood. Coal gas, coal tar, ammonia and coke are gained by the pyrolysis of coal.  Dry distillation is a case where gas is driven off from a heated solid and is then condensed and collected.  Mineral sulfates treated this way resulted in sulfuric acid when the gasses were absorbed by water.

*  Distillation of crude oil is preformed in an enormous type of still called a fractionating tower or column.  In such a tower the lightest and most volatile “fractions” are the first to rise to the top after the application of heat.  The liquefied petroleum gases such as butane, propane, propylene, butadiene, butylene, isobutylene are the first products to be removed and collected.  Next, in order of their vapor pressures; gasoline, naphtha, kerosene, diesel and fuel oil are separated.  An important phenomena occurring within such a column is “reflux”; an action where condensed vapors (liquid now) fall back down through the column, enriching rising vapors as they drop. 

Steam distillation is useful to extract many organic compounds that might otherwise be destroyed by the high temperatures in a normal retort still or reflux column.  With steam distillation, water vapor lifts vaporized particles from the mass and transports them to the condenser.  In effect the desired products are less damaged because distillation occurs at lower temperature.  Newer and more effective than steam distillation is vacuum distillation which lessens the pressure above the liquid mixture, effectively assisting in the quick evaporation of the lightest volatiles. 

Tiny amounts of essential oils can be extracted from plants by steam distillation or by solvent extraction.  Essential oils are the “essence” of a plant’s fragrance.  They are a concentration of ‘volatile aromatic compounds’ which are in effect only small molecules that change physical state from a liquid to a gas very quickly.  Volatile aromatic compounds move through the air quickly to stimulate the olfactory sensors in our noses.  Essential oils are used in medicines, foods, cosmetics, soaps, cleansers and perfumes.  They are frequently contained within oleoresins.

Lacquer, Shellac and Varnish

In general, lacquers are differentiated from paints by virtue of being more glossy.  The word “lacquer” is derived from the lac insect and a Sanskrit word for the number 100,000.   Millions of these little insects are cultivated for the purpose of secreting a resin that they produce after sucking sap from a tree.  “Shellac” (mostly coming from India) is the filtered and refined bug resin that makes such a useful wood finish and dye for both fabrics and leathers.  There is also a long established lacquer in the orient which is extracted from the Chinese or Japanese “lacquer tree” (Toxicodendron vernicifluum).  This tree sap which turns into a strong safe clear film once dried, actually contains the same poisonous irritant as “poison ivy” and therefore is difficult to work with when wet.

One or two centuries ago westerners tried to imitate the effect of Oriental shellacs and lacquers with what are called “varnishes”.  Omitting synthetic alkyd and polyurethane examples, the best (natural) varnishes came from dissolved copal resins.  Varnishes can be categorized by the type of solvent used.  ‘Spirit varnishes‘ for instance usually use alcohol as the solvent, but occasionally employ naphthas (the lighter liquid petroleum fractions) also.  Certain resins when mixed with these solvents dry fast and hard.  The film may stay clear (does not yellow with age) but the “spirit varnish film” is thin and brittle and not very durable.  ‘Essential oil varnishes‘ will use a heavier solvent like turpentine mixed in with the resin.  While this makes a tougher film than spirit varnish, it may take a long time for the solvent to dry.  Finally the ‘fixed-oil varnish‘ employs a resin mixed in with a “drying oil” like linseed oil. This makes the toughest, thickest most durable film or varnish of all.

   Latex paints might use water soluble acrylic resin, vinyl acrylic or styrene acrylic as binders.  White glue (like Elmer’s ® glue) that children soon become familiar with is actually polyvinyl acetate (PVA or “caparol”) and has the same composition as cheap latex paint.  There is no real latex in ‘latex paint’ actually.  “Latex” should denote natural rubber extracted from a jungle tree, not a synthetic polymer.  Acrylic resin, vinyl acrylic (PVA) and styrene acrylic bound paints are erroneously called latex in the U.S., but their called “emulsion paints” in the UK.  Their chemical composition is complex and far beyond the capability of the average person to replicate.

*  Acrylic resin is about twice as expensive as vinyl or styrenated acrylic.  A typical interior ‘latex paint’ contains about 20% acrylic and 80% vinyl.  Latex paints were unknown before the 1930’s or 40’s.  Prior to that time exterior paints were often made with linseed oil binder and interior paints were often based on milk (casein).  Today’s interior latex should be considered superior in most every way to yesterday’s casein or milk paints.  Exterior latex may exhibit good durability and fade and crack resistance but has not yet completely displaced old fashioned oils.  Here linseed based or alkyd based oil paints are extremely durable themselves and unlike acrylics will often penetrate deeper below the surfaces of wood and rust.  Exterior latex with 100% acrylic binders preform very well though in terms of UV resistance and in alkali resistance when applied to concrete & masonry.  Cheaper, predominately vinyl acrylic latex does well inside where smudges and grime may need to be scrubbed from walls.  Styrenated acrylic latex paint is often used on ceilings; its also good as a concrete or masonry sealer because it resist alkali burn and efflorescence (that situation where salt leaches through to the surface of concrete or another porous material and forms crystals).

   Alkyd paints were invented in the 1920’s, improved upon and used sporadically by some in the 1930’s and were commercialized in the 1940’s.  DuPont produced its first alkyd paints for artist in 1931.  The word “alkyd” (or “alcid”) is derived from the words “alcohol” & “acids”, which are both required to make the polyester.   Alkyds are polyesters manufactured from polyols (alcohols), aromatic acids and organic fatty acids.  Alkyds have become the most common “oil-based” type, premixed paints that are commercially available.  Since alkyds are made from both petroleum and vegetable products they are also reduced or thinned by most petroleum solvents or vegetable oils.

   Epoxy polymers are mixed with complimentary hardeners to produce whats called a thermosetting resin.  A thermoset is at first wet or soft before it becomes hard, insoluble and irreversibly cured.  Thermoplastic polymers on the other hand are pressed or injected into molds using heat.  Epoxy resins are important engineering or structural adhesives but they are more frequently being used as tough paint coatings by industry as well.  The surface paint or a priming undercoat of an automobile may be epoxy resin because of the superior adhesion and corrosion resistance this paint provides for metal.  Many water pipes, rebar (iron bars used to reinforce concrete), appliances like refrigerators, stoves, laundry driers and washers are covered with epoxy powder coat called FBE (Fusion Bonded Epoxy Powder Coatings).  Epoxy coatings are more heat resistant than latex-based or alkyd-based paints but they still deteriorate under UV exposure.  Like both latex and alkyds, epoxy resin was thought up and perfected by chemist rather recently (the 1930s).

  Nitrocellulose lacquer:  Many women paint their fingernails with the same chemical used to make gunpowder.  General Motors began painting automobiles with the lacquer in the 1920’s.  Nitrocellulose (guncotton or collodion or cellulose nitrate) was not the first “high explosive” because “nitrostarch” was discovered or invented about thirteen years before.  The inventions of nirtoglycerin and then dynamite would follow, not precede guncotton.  In 1846 nitrocellulose was apparently discovered or stumbled upon simultaneously by three different chemist working concurrently in separate laboratories.  It was made by saturating plant cellulose (like cotton) in nitric acid.  Nitrocellulose became the main ingredient in smokeless gunpowder and it became a support for photographic film.  It was probably the first plastic, and as a substitute for ivory it was soon molded into piano keys, billiard balls, tool handles and so on.  Nitrocellulose was also used to make the first transparent plastic roll film used for photography and it was used as a binder for tough, glossy automotive paints.

* Before nitrocellulose, nail polish might have been made from a mixture of gum Arabic, beeswax, egg white, gelatin and vegetable dye.

* The most common nail polish remover is acetone but his can be harsh on skin and nails. Sometimes ethyl acetate is preferred and this us usually the original solvent for nail polish itself, anyway.

* Before Henry Ford started making millions of his Model T’s, the other car makers used oil paints to accent their automobiles. As early as 1865 commercial oil paints began to appear that had extended shelf life due to the addition of sodium silicate (see waterglass or Keimfarben above). Based on slow drying linseed or tung oils these other car paints might have taken several weeks to harden. These oil based paints looked good for a year or two until ultraviolet light from the sun began to fade, yellow or dull the color. Ford’s innovation was to develop asphalt-based baked enamels for his cars that were similar to a paint technique called “Japanning”. Japanning is a dark decorative patina or finish acquired by painting a thin layer of bitumen (asphaltum) over an object but allowing some of the original surface to show through. Ford saturated his fenders, hoods and other metal parts with Japan Black (a paint bitumen) suspended in linseed oil and tinned with either mineral spirits or petroleum naphtha. The wooden components used a different paint recipe. Then as Japanned ornaments usually are, the metallic parts were baked in a tunnel oven for about an hour on a separate, slow moving assembly line. At the height of production a new Model T – with paint thoroughly dried – rolled off the floor about every three minutes. Drying time was not the only consideration for Ford, because the black paint job was much cheaper and ultimately more durable than what the competition was producing.

* Pierre DuPont owned stock in General Motors, years before his chemical company developed nitrocellulose paint lacquers. Around 1923 GM hit the automobile market with cars painted in new colorful “Duco paints” (pyroxylin / nitrocellulose based). These paints came in every color of the rainbow and took only minutes to dry. In the 1930’s the first metallic car paints appeared. These used real fish scales at first and eventually graduated to cheaper aluminum flakes. Sunlight resistant clear coat enamels for cars appeared in the 1940’s. The first synthetic polymer / transparent thermoplastic, “acrylic resin” car coats appeared in the 1950’s. These had the advantage of drying much faster than enamel coats. Acrylic lacquers were eventually superseded by what is preferred today, which is usually called a “clear coat finish”. A clear-coat-finish usually consist of a primer, a color coat and a clear, tough, polyurethane topcoat.


Fillers are intended to increase and extend the coverage of paint. Fillers are cheap, non-essential components that add bulk and might sometimes influence opacity. Example fillers include: clay, chalk, powdered marble / calcium carbonate, mica, baking soda, plaster of Paris, tile grout, sugar and vinyls like polyvinyl chloride or polyvinyl acetate.


Practically any attractively colored earth can be used for homemade pigment.  A good way to process it is to boil a quantity in water for several hours.  Strain out the impurities and larger aggregate and pour off the excess water.  Place the still moist residue in shallow pans and allow to dry.  Grind further in mortar and pestle if possible and sift once more through a finer screen or filter.

Pigments are insoluble color particles that require a binding agent to hold them onto the surface of the material being covered.  The first pigments came from the earth and from inorganic metal oxides.  This limited and somewhat dull spectrum or pallet of colors was eventually broadened and enhanced during the early 19th century.  Some new colors were created then, when mixtures of metal oxides and earth pigments were cooked and fused together under high heat.  Finally, by the end of the 19th century, advancements in a new field of science known as organic chemistry enabled the creation of several intensely vibrant colors.  Modern synthetic pigments, inks and dyes are based upon the carbon molecule and were created in laboratories.  Today almost every natural pigment has been replaced by a synthetic organic alternative.  Modern pigments behave differently, not necessarily better than older mineral pigments in that when mixed or thinned down they generally shift in “value” and not in “chroma”.

https://commons.wikimedia.org/wiki/File:Munsell-system.svg This image © 2007, Jacob Rus

Some common earth pigments include green earth, goethite, ocher, hematite, sienna and umber.  Some natural mineral pigments include Malachite, Vermillion and Lapis Lazuli.  Some artificial mineral pigments not found in nature are Venetian Red and Caput Mortuum.   Some organic pigments of natural origin would include carmine, gamboge, Indian Yellow, madder root and mummy brown.  Some synthetic inorganic pigments that are manufactured include Ceruleum blue, Prussian blue and Cobalt blue, Cadmiums and White Lead.  Some synthetic organic pigments (lab created / carbon based) include the azo pigmens, dioxazine, isoindolinones, quinacridones and phtalocyanines.  There are too many pigments with too many details to define them all properly here.  Entire books have been dedicated to the subject. The vast majority of pigments available in the marketplace today are actually synthetic.   A short, far from complete list of traditional, non synthetic paint pigments follows.

Green Earth is similar to ocher; a mixture of ferrous hydroxide and silicic acid.
Goethite (Brown Ocher) is a unique mixture of ferrous hydroxide.
Ocher (usually a yellow) is a clay that contains hydrated hematite (an ore from which iron has been smelted for the last 6,000 years).
Hematite (usually red unhydrated mineral iron ore) stems from a Greek word for blood. “Limonite” ore comes from the Greek for meadow (meadow/ marsh/ bog ore/ brown / yellow). Ocher then is a catchall phrase for abundant natural earth pigments containing iron oxide and depending upon hydration states and additional ingredients may range in color between yellow, red, purple and brown. The artist and painters of the Medieval and Renaissance period knew how to cook ‘ochers’ with heat to drive away the chemically bound water, achieving unique hues.
Sienna (usually brown) is a mixture of iron oxide and manganese oxide. Yellowish-brown “raw sienna” is turned into a reddish-brown “burnt sienna” when cooked with heat.
Umber (both raw and burnt) is also a mixture of iron hydroxide and manganese oxide. It is usually darker than either ocher or sienna.
Malachite (usually green) is a hard copper carbonate mineral. It often comes from underground stalactites. <pic>
Ultramarine (deep blue) was originally made from crushed Lapis Lazuli. It was an extremely expensive pigment that was hard to make and it was used sparingly. <pic>
Venetian Red pigment comes from red iron oxide but it is artificial because it is or was collected from heated chemical waste of manufacture.
Caput Mortuum (usually purple) from Latin – meaning “worthless remains” was usually collected from leftover, useless iron sulfate (copperas) residues.
Carmine pigment (crimson or bright-red) is obtained from carminic acid.  Since carminic acid wasn’t reproducible in the laboratory until 1991, it has since ancient times been acquired by crushing up little scale insects.  Polish cochineal and Kermes dyes were both from scale insects and known in ancient Europe and were later valuable commodities in the Middle Ages.  Mexican or Spanish cochineal (from a different, New World scale insect that eats prickly pear cactus) quickly became the preeminent scarlet dye in the 16th century.  Although carmine or cochineal are better known as food colors, lipstick and fabric dyes today, artist like Michelangelo also used them in paints.
Madder root has been used since antiquity as a (red) dyestuff, but it has also been used for tinting paints. It wasn’t known in Europe until returning Crusaders brought it back to Italy. During the Colonial Period the typical red uniform of the British Army was dyed with madder root, while the officers that could afford it had their own uniforms tailored and dyed with brighter and more colorfast carmine or cochineal dye.
Gamboge is a saffron / mustard yellow pigment that is obtained from the sap or resin of a tree. It is the traditional color and dye used for the robes of certain Buddhist monks. It is often used in watercolor but is not lightproof.
Indian Yellow is was collected from the urine of cows that ate mostly mango leaves. It is a natural organic “lake” pigment. Authentic Indian Yellow is quite permanent, very expensive and often imitated.

Uranium Yellow from uranium oxide; often found in vanadium ore, made a useful pigment before the Manhattan Project found a better use for every available bit of the element in the 1940’s.
Orpiment (yellow) and Realgar (red) were both popular since Roman times as pigments.  The two pigments differ slightly in chemical composition but both consist of poisonous arsenic sulfide.  Arrow tips were occasionally dipped into solutions of these minerals to make them more deadly.  The minerals were originally found as crystalline deposits nearby volcanic fumaroles and geothermal hot springs.
Vermillion (bright red or scarlet) comes from the crushed crystal of mercury sulfide known as “cinnabar”.
Emerald Green was a very poisonous and dangerous pigment made from copper arsenate. By itself it made a durable and attractive pigment but would later turn black if mixed with sulfur colors (like cadmium yellow, vermilion and ultramarine).
Mummy Brown was a very useful and popular paint pigment made from the crushed up remains of Egyptian mummies. Most artist in the past did not know of its true origin. Perhaps some pigment called mummy brown was produced by burning ‘green earth’. Mummy Brown was still being made in the 20th century until sources of available mummies finally ran dry.
Asphaltum or bitumen is a brown / black pigment derived from solidified petroleum. It might be used as a binder for gravel and sand in asphalt road surfaces but it has also been used as a pigment. Ancient aboriginal N. American Indians used it to decorate pottery and Henry Ford used it to paint automobiles.
Ceruleum Blue; a synthetic inorganic pigment made from copper and oxides of cobalt
Prussian Blue (also Paris Blue or ferric ferrocyanide) was the first modern synthetic pigment. It is a dark blue, non poisonous, iron-cyanide based compound with intense chromatic power. It was the main color of uniforms used in the Prussian Army and was the traditional blue used in “blueprints” (or cyanotypes – which exploited the light sensitivity of paper perhaps, coated with gum Arabic & ferro-gallate (acidified iron) type solutions).
Cobalt Blue is made from heating together cobalt and aluminum oxide. Some Chinese porcelain pottery has mixed the same minerals for many centuries but blue glass and cobalt blue paints have been used now for about 200 years.
Cadmiums are very vibrant and light-fast yellow, orange and red pigments made from oxides of cadmium. They are expensive pigments, potentially toxic and superior to modern organic alternatives in almost every respect. <link Europe ban>
White Lead (or Cremnitz White) is lead carbonate and has historically been the principal white pigment of classical European oil painting. When mixed with a dryable oil it spreads wide and covers especially well and with high opacity. White lead paint was once commonly used to protect the hulls of wooden ships from shipworm. Unfortunately lead paint has been banned in most countries because of its potential toxicity and ‘titanium white’ has replaced it. Lead carbonate is the same substance that forms white crystals on terminals of a car’s battery. Historically the pigment was produced by subjecting lead to the fumes of strong acetic acid <vinegar>. Red Lead paint on the other hand is lead oxide and was once very valuable as an anti-corrosion / rustproof primer paint. For example this primer distinguished and protected the Golden Gate Bridge near San Francisco for thirty years before re-painting became necessary and before the formula was changed.
Titanium White is titanium dioxide (Ti O2) and is non poisonous. It has great covering power and is bright – with a high refractive index.
Zinc White is zinc oxide. It is a very useful non toxic pigment developed about 170 years ago that tints less or is more transparent than titanium white.
Zinc Chromate when used as a pigment was known as Zinc Yellow.  It is not used in art anymore because it degrades quickly to brown and is toxic and carcinogenic.  Zinc chromate does make a very useful paint coating in industry where it is used to passivate (protect from corrosion) metals like tin alloy, galvanized steel, cadmium, magnesium and aluminum Metal tools that have undergone a chromate conversion coating usually display a distinctive yellow-green iridescence.

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Again, the difference between a pigment and a dye is that one is soluble and the other is not.  Inks incidentally, can be either dye-based or pigment based solutions.  Paints need a binder to hold little solid particles of color pigment to a surface.  Dyes on the other hand contain infinitesimal refractive coloring compounds that are dissolved in solution.  Pigments are generally better than dyes in keeping their color by resisting damage from high heat, bright light or chemicals.  Dyes can cling to or be absorbed into only a few types of surfaces.  Without special preparations, dyes cannot be turned into the pigments used to color paints.  Therefore a “laked pigment” is one wherein a soluble dye is absorbed by or chemically bonded to a transparent insoluble salt; which then leaves behind a particle of insoluble pigment.  Calcium salts from sources like bones, chalk or white clay were historically the first salts used to entrap dyes for use as pigment.  Today chromium and cobalt metallic salts are more frequently used to manufacture lake pigments.

From ancient times people have been dyeing fabrics and leathers and furs.  Woad, weld and madder are natural dyes that have been used for the last 3,000 years or more.  Today dye chemist are busy designing ever better molecular dyes, for the examination of neurons in a nervous system or to study DNA by examining specific genes.  Other dye chemist might be busy perfecting a contrast dye for use by an MRI (Magnetic Resonance Imaging) machine or inkjet solutions for 3D printing or microcircuitry fabrication.  Here they would need to consider electrostatic properties, solvent compatibility, resistance to bleeding and spreading, consistency and flow properties or perhaps the adhesion of dye or ink to a substrate.

Wool and other so-called “protein fibers” like hair and silk are the easiest fabrics to color with a natural dye.  First the oils on fibers like wool need to be washed or “scoured” away before a dye can penetrate.  Cellulose fibers like cotton, linen, flax, hemp, jute, paper, cane, rattan, etc. are less suited to natural dye uptake and may need to be treated beforehand by a mordant.  A mordant is a chemical used in solution that helps embed color into a fiber.  Taken from a French word that means “to bite” or to take hold, a mordant allows the penetration of a dye into fiber,  similar to the way a laked pigment binds within a crystal.  Some “substantive” or “direct” natural dyes like those from walnut hulls, Tyrian purple from a sea snail, lichens, onion skins, tea or coffee will stain and stick to wool without the help of a mordant, but these might eventually wash out or fade.  Substantive or direct dyes without assistance of a mordant cling to fibers by relatively weak hydrogen bonding.  Other types of dye molecules however can attach to fiber molecules by complicated Van der Waals forces or by ionic or convalent bonding.  The most permanent dyes are fiber reactive dyes that establish strong covalent bonds.

The most common mordants are alum, copper sulfate, chrome, iron sulfate, tannic acid and tin.  Some of the direct dyes already contain a tannic acid mordant (ex: walnut, oak and pecan husk, tea & coffee).  The choice of mordant will usually influence the outcome of the dyed color.  Alum (aluminum potassium sulfate) causes the least change in color.  Copper sulfate (Blue vitriol) sometimes turns fibers green.  It can be collected by soaking dirty old pennys in acid.  Iron sulfate (copperas) “saddens” color and makes them more green-brown or gray.  Historical “iron gall ink” employed iron sulfate.  Copperas can be made by soaking rusty nails in sulfuric acid.  Tin (stannous chloride, specifically) brightens colors, especially reds and yellows, but it can be very harsh on fabrics.

To bring this complicated topic to a shortened end so that this blog post can be published today rather than next month; many details about dyeing will need to be skipped for now.  The goal at present is to explore dyes insofar as they intersect with pigments and paints.  Perhaps this segment on dyes will be amended later.  More time is needed to compress information and to insert little details.  For instance, for forty years following its invention TNT was used only as a yellow dye.  TNT is so insensitive it took that long to find a satisfactory way detonate it.  Poke berries are not commonly used for either dye or ink; but the final draft of the American Declaration of Independence was penned in fermented poke berry juice.

Paint recipes

The Internet is loaded with recipes for children’s paints.  These may contain binders of soap, glue or flour and pigments of Kool Aid ® or food coloring and the like.  One may find a recipe for creating a paint from egg yokes and colored chalk.  { Michelangelo may have used the same tempera ingredients on the Sistine Chapel but since he painted upon wet plaster the work is called fresco, remember }.  Digging deeper one can find recipes more applicable for bulk paints.  There is no need to replicate here, the work already done on another web site.  One decent site providing information for homemade paint is provided by motherearthliving.com.  The following list of ingredients for “Clay paint” is copy and pasted here, as insurance against the possibility of “link rot” in the future.  The paint’s final color would be determined by both the hue of the powdered clay chosen and by any auxiliary pigments added.

1 part wheat, rice, rye, or potato flour
2 parts cold water
1-1/2 parts boiling water
1 part powdered clay
1/2 part inert powder filler (options: mica flakes and powder, chalk, powdered ­marble or silica, 60- to 80-grit sand for rougher surfaces)

Gritty “chalkboard paints” similar in texture and performance to the slate chalkboards found in old school rooms can be created from either commercial latex (emulsion) paints or homemade paints.  One simply adds plaster of Paris, baking soda, un-sanded tile grout or calcium carbonate to the paint.

A simple black paint can be made from potatoes.   Several potatoes are slowly baked in a fire or in an oven until they turn completely black and dry inside.  These are then crushed to a fine consistency and the powder is mixed with linseed oil.  For a useful olive drab (Army green) color one can add yellow ocher pigment.


From a copper engraving of a plague doctor in Rome, circa 1656

Across Europe between the the 14th and 17th centuries, a number of ‘Plague doctors’ donned protective suits like this to walk among dead and dying plague victims. Unsure of what might be causing these plagues, these suits were armor against a hazardous environment and are quite reminiscent of modern day hazmat suits. The image above depicts a late example from the city of Rome, complete with heavy cloak, leather gloves, glass goggles and conical birdlike beak covering the mouth and nose.  The impression of a carrion eating, scavenging crow or raven is almost impossible to miss.  Perhaps this engraving was intended as an early macabre from of editorial cartoon.  The significance of the conical or pointed beak is that various herbs and powders were stuffed into its end, in hopes of filtering out any lurking invisible plague vapors that might be inhaled.

Today, centuries later, some carnival costume mask may remind us of those heinous plagues. During the “Black Death” as much as half of Europe died in the span of four years.  There were many large epidemics  in history that are somewhat erroneously called “plagues” since these were probably not caused by the infectious pasteurella pestis bacillus. From antiquity to present the number of proper plague outbreaks caused by this bacillus though, might still number well over one hundred.  Between the 14th and 17th centuries the plague quit, then returned about 15-20 years later (almost with every generation).  The European rat population (where the bacillus is apparently not endemic) was repeatedly wiped out and took time to recover as well.

It is generally accepted however that there were three ‘great waves’ of plague pandemic in world history. The first noticeable “great” plague is called the “Plague of Justinian”. It occurred in 541 AD and was centered in the Eastern Mediterranean / Byzantine Empire area. As many as 5,000 people a day died in the streets of ancient Constantinople (by far the largest city in Europe at the time – named Istanbul today). In a year’s time this bout of plague killed perhaps 25 million people including the emperor Justinian himself.

The next and biggest great die-off is known as the “Black Death” which began in 1346 and lasted for seven years. This plague decimated perhaps 75 million people or approximately 1/6th of the world’s population. It is thought to have made its way from China or Central Asia (where the bacillus is indigenous in local rodents) along the Silk Road by caravan to the Mediterranean Ocean where ships carrying other rats or mice – further disseminated bacillus carrying fleas to ports throughout Europe and North Africa.   Europe especially, was remodeled by the Black Death.

The less disruptive, less specific “Third Pandemic” as it is called, lasted for more than a century (between 1855 and 1959) and was responsible for at least 12 million dead in China and India.  During this period the pneumonic form the plague ran rampant in Mongolia. All of the major epidemics of plague are thought to have originally blossomed outward from Central Asia.   Right now the pasteurella pestis bacillus can be readily found on any day, in the dirt or among rodent colonies living on the Asian, African, North or South American continents.  There is an ongoing occurrence of bubonic plague today, in Madagascar which broke out in 2014 and hasn’t yet faded away.

In humans the acute infectious disease caused by the bacillus Pasteurella pestis occurs in three forms: bubonic, pneumonic & septicemic.  The most common form bubonic, is characterized by buboes (bumps or blisters / inflammatory swelling of a lymphatic gland, especially in the groin or armpit).  Pneumonic plague  infects the lungs instead of lymph nodes.  Less common than the bubonic form but more deadly, the pneumonic form can be contracted by a flea byte or by airborne inhalation of the virus from an infected person.  Septicemic plague attacks the blood and causes blood clots but is rare.  Which ever form of plague is encountered, treatment with antibiotics has supplanted the treatment with sulfa drugs used in previous decades.  Early detection is still paramount for survival.

Segue to Vinegar

Vinaigre des 4 Voleurs / Four Thieves Vinegar

There is a story with various versions that dates back to one outbreak of plague in the city of Marseilles, France.  It seems that four incarcerated thieves (possibly caught for robbing the sick or dead) were pressed into labor.  They were forced to handle, transport and bury the corpses of plague victims.  Miraculously, the thieves continued to survive this punishment detail day after day while others about them were dying like flies.   Apparently the thieves routinely applied a concocted ointment they received from a local medicine woman.  Their survival was probably the result of certain herbs in the ointment acting as a repellent to the plague carrying fleas that transmitted the pestis bacillus.  The salve or ointment started with white wine vinegar as a foundation to dissolve and preserve the essence of these herbs.  In a version of the “Four Thieves Vinegar” believed to be authentic; angelic, horehound, meadowsweet, wild marjoram, campanula, camphor, cloves, rosemary, sage and wormwood were used. At least the last six herbs listed have aromatics that repel insects – like parasitic plague infested fleas.

The English word “vinegar” comes from the French phrase “vin aigre” – which means sour wine.   For as long as mankind has had alcohol to drink (about 9,000-10,000 years) he has had vinegar too.   The ancient Babylonians used vinegar as a condiment and Cleopatra used vinegar to win a bet.
Any plant sugars in solution can be fermented to create alcohol.  That alcohol (ethanol) can by deliberation or by neglect be exposed to open air and subsequently turned into vinegar by a different fermentation caused by acetic acid bacteria.

The “acetobacter” genius of the acetic acid bacteria (acetobacteraceae) family is the one most commonly used to make vinegar or to supply vinegar fermentation starter cultures (often called the “mother of vinegar”).   Products that are labeled vinegar usually contain a minimum of 4% acetic acid while the remainder is water, flavorings and trace chemicals.   Vinegar doesn’t spoil if sealed and has a practically indefinite shelf life.  It may oxidize, lose its aromatics or lose some water to evaporation if exposed to open air but it does that slowly .

Types of vinegar

The most common vinegars are cider, wine, malt, rice, balsamic and distilled. Today those have been joined by many flavored or seasoned variants. Vinegar can be produced from all sorts of things including coconuts, honey, beer, maple syrup, potatoes, beets, malt, grains, molasses, dates, sorghum, fruits, berries, melons and whey.

Wine vinegar is self explanatory.  It can occur in a few weeks or months after acetic acid bacteria in the atmosphere come into contact with wine. Aceobacter can spoil a soggy wooden wine barrel for example, if this is left too long unfilled and unused.   Malt vinegar which is popular with “fish and chips” is of course equivalent to spoiled beer.   Beer is usually fermented from barley and barley malt.   Scotch whisky can be made entirely of malted barley.   Malt is grain that has been germinated and has started to sprout.   The term “distilled vinegar” is a tad bit misleading because the vinegar itself is not distilled – but it is made from a concentrated source of ethanol. Authentic “Balsamic vinegar” is a very prestigious and expensive product that is first cooked and reduced from a white grape must, then fermented and then aged for a very long time in a succession of different aging barrels.


* “acid is second only to salt for elevating the flavors of your cooking. Just a few drops of acid in the form of citrus or vinegar can make a dish more complex — “brighter”

Vinegar is an important foodstuff and food preservative.  Vinegar can also be used to remove rust, prevent dandruff, soften stiff paintbrushes, kill warts, clean glass, clean tile grout and toilet bowls.   Like a vinaigrette salad dressing, a mixture of olive oil and vinegar make a fine furniture polish.   After the famous Holy Roman Emperor / King of Germany and Italy known as Frederick Barbarossa (1122-1190) drowned in the Saleph River (modern day southern Turkey) during the Third Crusade, his army collapsed.   His body was put into a wooden barrel and preserved with vinegar for the long trip back home.

Many sauces and food condiments like mayonnaise, tomato ketchup, spreadable mustard and pickle relish contain vinegar.  When Americans see a preserved cucumber they say “pickle” while in Ireland, Australia or the UK people might call the same item a “gherkin”.   A gherkin is actually a variety of cucumber and a cucumber is far from the only produce that can undergo the “pickling” process.   Beets, carrots, onions, tomatoes, cauliflower, cabbage, peaches, cherries and pears are frequently pickled as well.   There are several variations of the pickled cucumber or gherkin including: half or full sour, Polish style, sweet, dill, kosher, bread & butter and cornichons – those tiny little tart French pickles preserved with vinegar and spiced with tarragon.

Salt which was treasured in the ancient world, was used to preserve meats, eggs, vegetables and fruit because it drew moisture out of the foods and in so doing it inhibited the development of bacterial spoilage.   Produce can be preserved by a few different salt curing methods like dry salting, brining (strong salt solution), low salt fermentation and pickling.  Low salt fermentation and pickling with vinegar are similar processes in that lactic acid created in the first instance or acetic acid introduced by the second process, both lower the pH to a level that is hostile to bacteria. It takes a pH of about 4.6 or lower to kill most bacteria.  Clostridium botulinum is the tough, resilient and dangerous anaerobic bacteria that can flourish in stored foods that do not have high enough acid concentration or that were not heated hot enough or long enough when they were canned.

There are two traditional ways to go about pickling; the slow way by fermentation or the fast way with vinegar.  The fast way involves soaking some vegetable example in a salt bath overnight. This removes some water and better allows vinegar afterward to penetrate the vegetable’s tissues.   Alternatively, pickling lime (calcium hydroxide) is used instead of salt for this initial step.  Lime has the effect of making a vegetable like the cucumber crisper; it is there for the texturing effect alone and not for preservation.  The lime or salt solution is rinsed off after about 24 hours.  Vinegar, accompanied usually with antimicrobial pickling herbs and spices (like cinnamon, mustard seed, cloves & garlic) is then added.

German sauerkraut, Korean kimchi, sour and dill pickles are examples of the slower fermentation method of pickling which might require a couple of weeks to a couple of months.   Surrounding produce in brine solution deprives undesirable bacteria (most types) oxygen to grow but creates a favorable anaerobic environment for lactic acid bacteria.   Lactobacillus bacteria then ferment or convert natural sugars into lactic acid.

* A typical process for making sauerkraut using this slow pickling process is to place unwashed shredded cabbage into a sterilized stone crock.   Some outer leaves on the cabbages may be removed but wild yeast are to be otherwise retained.   Salt is repeatedly sprinkled between thin layers of shredded cabbage and packed firmly down.   Finally a dinner plate or something similar and additional weight (preferably in the form of a limestone rock) presses everything down; a sanitary cloth covers the crock.   In the process of waiting 4 to 6 weeks for nature to take its course: water is pulled by salt and pressed out by weight to form a brine solution.   Also a small amount of lime is dissolved from the rock which assists in the formation of lactic acid and provides the sauerkraut with extra flavor.

Products preserved by the two pickling processed mentioned above should be safe to eat for several months afterwards.   Cooking with heat and/or refrigeration will prolong their longevity as food.   High acidity should prohibit most bacterial growth but occasionally the acidity of vinegar (acetic acid) used or lactic acid fermented is not adequate.   To be considered safe for longer periods, even pickled foods need to be subjected to the ‘long time duration at elevated temperature’ of proper canning technique.

Making Vinegar

Just as with pickling there is a fast way and a slow way to make vinegar.  The fast way involves inoculating a liquor or fermented juice with a starter culture of bacteria called “mother of vinegar”.   “Mother” itself is a cellulose or complex carbohydrate that forms as surface slime on vinegar that is long exposed to air.  Acetobacter bacteria are aerobic which means they are oxygen loving or thrive in air.   In fast commercial vinegar production, a source liquid which already contains ethanol is started with this bacterial culture and extra air is added to oxygenate and promote the fastest fermentation.  The fast vinegar method may take only two or three days to complete.   Slow traditional methods for making vinegar on the other hand might require a few months – to a year to complete.  Here the acetic acid bacteria must be captured from the air before fermentation can even commence.  Here a potentially useful surface slime might build up that can be skimmed off and collected for use as mother elsewhere.

Homemade vinegar

Web pages can be found on the Internet which give step by step instructions for how to make vinegar from a bottle of wine for instance.  Usually these instructions call for the use of some Mother of Vinegar.   Little containers of this can be purchased online if need be, from places like amazon.com.  It is very easy however to make vinegar the old fashioned way.  The best results would probably be returned by starting with a jug of simple, unpasteurized sweet apple cider.  Taking the top off and letting the jug sit for a week or two will allow wild yeast to make the cider alcoholic.  Another few weeks of exposure to air will create apple cider vinegar.   Again, adding a little ‘Mother’ if it is available will help speed the process.  At some point after the homemade vinegar becomes strong enough, it should be bottled.  Vinegar should be stored in a narrow-neck bottle with a tight seal to prevent oxidation and loss of flavor.  New vinegar should be aged for at least several months, to clarify and allow the flavor to mellow.

* Vinegar eels are just barely visible and it would take about sixteen mature ones laid end to end to equal one inch in length.  These tiny nematodes () like to hang out and breed in vinegar.   They consume the bacterial and fungal microbes that form “Mother of Vinegar”.  These worms can inhabit many vinegar products that are left too long exposed to air, because their microscopic eggs often ride dust particles that float around in the air.   In the U.S., commercial vinegar is filtered or pasteurized to eliminate these little creatures, but they are not toxic or parasitic.  Like the brine shrimp that are larger, vinegar eels are actively cultivated and used as food for young aquarium fish fry (baby fish).   A hobbyist might grow a culture of eels from apple cider/vinegar because their eggs come with the apples naturally.

*To make juice, apple fruit must first be macerated and squeezed through a press.  Filtered this becomes apple juice, unfiltered this becomes soft or sweet apple cider.  Fermented the juice becomes alcoholic – hard apple cider.  If frozen, ice can be pulled out leaving less water so this more concentrated form of hard apple cider becomes “applejack”.   The same process can be accomplished with a bottle of wine or beer but some of the liquid must be removed beforehand to prevent ice from bursting the bottle when it expands.  Of course this process would be illegal almost everywhere booze is normally sold because it is considered to be distillation (freeze distillation).  You don’t want to deprive your government of one of its most lucrative tax bases.

*The drip still can be made from pots and pans from about the kitchen. Euell Gibbons published images of the concept more than fifty years ago. A simple apparatus like this is appropriate for collecting the oils and fragrances of herbs. Just toss a handful of rose pedals or other herb into the water of the bottom pot.  Apply heat and droplets of vapor will condensate and drip into the cup.


Considering Leather

The most utilitarian and multipurpose material ever readily available to early man came from the hide of an animal.  Making leather from hides or furs from skins might have been the first human industry.  Until the very recent dawn of plastics and synthetic fibers, leather and fur were nearly indispensable commodities.  Leather is a superior material for several applications like footwear, saddles and upholstery and still remains the material of choice over any synthetic alternative.  However, turning a smelly raw animal skin into usable leather is a difficult process.  Before certain procedural and chemical advancements in the previous century, commercial tanning was even yet a more laborious and time consuming pursuit. This post will endeavor to briefly separate and identify some of the varied techniques used in leather tanning, while perhaps empowering some readers with a few ‘do it yourself’ type leather tanning skills.

What is leather?

A mammal’s skin or hide consist of a thick center layer called the “dermis” or “corium” which is sandwiched between a thinner epidermis on the outside and a subcutaneous fatty layer on the inside.  The corium of a fresh hide contains between 60-70 percent water and 30-35 percent protein by weight.  Of that protein about 85 percent is of a special fibrous type called “collagen”.  These protein fibers are held together by chemical bonds.  Tanning chemicals (tannins, enzymes, acids, bases or salts) in effect alter these bonds between collagen fibers, remove water and dissolve natural fats within a hide.

If a fresh hide can be frozen, salted or quickly dried then it can be temporarily spared an otherwise inevitable decomposition from bacterial rot.  A fresh hide may have a few useful applications in raw form though, considering its tendency to shrink substantially upon drying.  However should dry rawhide be re-hydrated, it immediately becomes susceptible again to rot.  Raw hides have value and those destined for leather processing are soaked in brine or packed in salt at the slaughterhouse before being shipped to a tannery.  Should they desire, tanneries could preserve surplus hides for over a year by packing them in more salt.  Tanning is both a physical and chemical process that preserves a hide and converts it into leather.  The removal of membranes and subcutaneous fat from the underside and the optional hair removal on the topside entail just one or two physical processes.  The chemical processes reorganize some organic molecules, while often coating or replacing others with outright inorganic substitutes.

The leather industry has an odorous history and one accompanied by pollution. Today there are three distinctive methods to use for tanning a hide: by the ancient vegetable process, modern chromium process or novel aldehyde process.

Tanning liquors

Historically either alkali or acidic solutions have been used in tanning.  A Native American Indian might have soaked a deer hide in a potash solution for example.  Also called “lye”, this caustic alkali or base solution of potassium carbonate can be created simply by leaching water through wood ashes.  Lye (potash/potassium carbonate, sodium hydroxide/caustic soda & potassium hydroxide) or other alkali solutions like hydrated lime will remove the hair from hides.  Both sodium sulphide and sodium hydrosulphide will dissolve hair.   Even some weaker alkaline solutions like ammonia collected from human urine; have the effect swelling the hide, enlarging follicles and loosening hair at the root.

* Several centuries ago in urban areas like 16th century London, it was common practice for poor children to collect urine from private “chamber pots” and public “piss pots” to sell it for money.  Urine is a rich source of urea and decomposes into ammonia, which was an important source of nitrogen to factories that could not yet synthesize such a chemical independently.  At least three important industries required urine back then.  Textile manufacturers used ammonia for altering the color of vegetable dyes and adjusting pH in dye baths, gunpowder makers needed the nitrogen found in urine to make critical potassium nitrate and tanners also needed or favored urine to produce leather. 

* Even back in ancient Rome, urine pots were placed in the streets for the public to fill at leisure.  These pots were collected and used to wash laundry.  The laundry came out bright and clean and the practice was so popular that Emperor Vespasian taxed this urine in the 1st century AD.

* Today household ammonia (5 – 10% pure ammonium hydroxide) is still critically acclaimed for its general cleansing ability, including for laundry.  Just don’t mix ammonia with bleach (calcium hypochlorite) because that will create dangerous fumes.   

Two mildly acidic and astringent chemicals used to produce leather are alum and tannin.   Alum (or specifically hydrated potassium aluminum sulfate) is used as a blood coagulant in articles like styptic pencils, in underarm deodorants, as a dye-fixer or mordant for wool and plant fibers and in tanning solutions where the hair or fur might want to be retained.  Alum creates a less toxic alternative tanning liquor and for small jobs is being used more frequently now than it ever was in the past.  Tannin is easier to find as it occurs naturally in the bark and leaves of several different plants. This astringent polyphenol binds to and coats collagen proteins, making them less water soluble and less vulnerable to bacterial decomposition.  Tannin is but one type of polyphenol out of thousands, and these phytochemicals give vegetables and fruit both their color and beneficial antioxidant properties.

* Astringents taste bitter to the tongue, pucker up the mouth and tend to shrink or constrict body tissues in general. An astringent tanning liquor then can be expected to tighten its hold upon hair, as opposed to a lye liquor that would swell and loosen its hold. 

* Tannin from tree bark is far more traditional than tanning liquor from alum. By the early 17th century Industrial Revolution, large plots of the northern English countryside were being ravaged to mine alum rich shale deposits, which were then baked in bonfires using all the firewood from the surrounding landscape.  Probably more of that alum found its way into textiles than leather but by this time England was running out of trees too. 

In the past the commercial treatment of leather with tannin required massive amounts of tree bark (approximately an equivalent weight of bark to the weight of a skin).  In America, after the forest near early Boston and New York City were denuded, tannin harvesters ascended to the Catskill, Adirondack and Allegheny mountains to placate their ravenous need for tannin. Whole hemlock forests were flattened of trees, merely for the tannin in tree bark while the softwood was largely abandoned. The practicality of building tanneries closer to the source of tannin and then shipping hides long distance rather than tree bark was eventually realized.  Leather tanneries often formed the central economic hub of many new communities in American outward expansion.

The word “tannin” is derived from a German word meaning oak.  Several different plant species (including chestnut, eucalyptus, mangrove, maple, sumac, wattle, and willow trees or bushes) are high in astringent tannin and are commonly used in vegetable tanning liquors.  It would be possible to leach a tannin rich tea from the dead leaves of most any deciduous tree in the autumn.  Some people have boiled bran (the husk of wheat or rye kernels) to obtain tannin.   Hemlock tends to make leather reddish-brown while oak produces yellowish-brown and chestnut while famous for making thick Italian shoe-sole leather, turns collagen fibers dark brown.  Before introduction of chrome tanning solutions in 1858, most all leather produced was simply “vegetable tanned” leather.

Keith Weller acquired from USDA ARS (Website)

Keith Weller acquired from USDA ARS

So around the same time that the trans-American railroads were being constructed, Texas cowboys were driving cattle herds up to meet the railhead and jobless Civil War veterans were harvesting wild buffalo for meat; new chromium leather tanning techniques were suddenly gaining favor in Europe.  The new rails were soon used to ship cattle back east (notably to Chicago) and products like buffalo hides back further east to established tanneries perhaps in Boston or New York City.  The fact was that those eastern American tanneries relied upon much human labor and slow vegetable tanning chemistry.  Typically a cow hide might need to soak in a barrel of tannin liquor for six months to produce high quality leather.  Although not especially desired or in demand by American tanneries, a few bundles of Buffalo hides made their way to England; where they were enthusiastically received and thousands more were immediately ordered.  The decimation of the great American Bison herds is directly traceable to bovine diseases spread from domestic cattle and the commercial slaughter demanded by global economics.  In a twelve year period beginning in 1871, about six million buffalo hides from approximately nine million animals slaughtered – were shipped to Europe.


Somewhere back in the middle of the 19th century, the effects of Chromium (III) upon a rawhide were discovered.  These solutions came from dissolving elemental chromium in sulfuric or hydrochloric acid. Two solutions, chrome alum (or chromium (III) potassium sulfate) and chromium (III) sulfate are noteworthy in tanning.  The latter of the two solutions is the simpler, cheaper form preferred today by the commercial tanning industry.  Not nearly as toxic as the hexavalent chromium (IV) variety of chrome used on shiny automobile parts, chromium (III) tanning liquors nonetheless contain heavy metals and should be disposed of carefully.  In the right pH environment chromium (III) can oxidize into undesirable and environmentally persistent chromium (IV).   Chromic acid which is different but related, is noteworthy for being a strong and corrosive, oxidizing agent that will attempt to consume organic compounds.

About 85 percent of all leather today is chrome tanned.  ‘Chrome tanned leather’ is thinner, more eaten away and more flexible than ‘vegetable tanned’ leather.  Chrome tanned leather is good enough though for most situations and may even be the preferred choice in a few applications; given its flexibility and better resistance to shrinkage caused by water.  Some chromium remains behind in the hide after tanning, as it is tightly bound to the collagen proteins.  The reason that chromium has become so ubiquitous in today’s tanning industry is because it allows great reductions in both time and labor.   Vegetable tanned leather which is more expensive, is usually reserved for quality items like belts, purses, wallets, shoe soles, horse bridles, harnesses and saddles.

Both vegetable but especially chrome tanned hides are tumbled and pounded around in rotating drums like the museum piece imaged above.  Once the desired level of chrome penetration into the hide is achieved (which takes about 24 hours) the hides will come out “wet blue”; not the tan color shown.  Several varied finishing techniques would follow next.

Whereas vegetable tanning might require grueling labor for fleshing and stretching the hide and long months of exposure to tannins inside a vat, chromium tanning creates a product in just days or weeks.  The substantial chore of fleshing is much simplified by virtue of these chemicals dissolving most of those unwanted fatty tissues. The details of temperature, pH and other chemical factors are more complicated, critical and caustic with chrome than with vegetable tanning liquors.  In this present day and age, one can no longer just buy U.S.P. approved chromium potassium sulfate crystals from the local drugstore either.  Chrome tanning on an individual basis is not practical, but vegetable tanning is.

Aldehyde Tannage 

While chromium (III) solutions leave tumbled hides a color that is referred to as “wet blue” a newfangled process leave the hides “wet white”.  The first and most notable, quick working base chemical used in “chromium-free” aldehyde-tanning was the water soluble gas, formaldehyde.   Not creating the pollution that chrome does, some small amount of toxic formaldehyde residues nonetheless remain within the clothes, shoes and car seats made with this leather.  A newer chemical called glutaradehyde is highly reactive towards proteins, but leaves aldehyde wet white leather comparatively ‘baby safe’ and allergen free.  Glutaraldehyde is more expensive than formaldehyde, it sterilizes or inactivates viruses and bacteria, it is used to remove skin warts and is occasionally used in hydraulic “fracking” fluids to unclog oil wells of microorganism buildup.

The American Indians and probably many other nomadic aborigines as well typically used the brains of an animal during the hide tanning process.   Boiling the brains with a bit water creates an oily soup that can either be used as a solution to completely submerge and soak a hairless hide or be rubbed into the underside of a fur.  Once the treated skin is smoked over a fire however, chemical changes occur and a mild aldehyde type tannage takes place. Almost any organic oil benefits the flexibility and durability of leather.  Some famous leather ointments like Neatsfoot oil however will darken leather while brain oil is less likely to.

*Neatsfoot oil (a brand name) actually comes from the tibia (lower leg –shin bone) of a cow; it doesn’t easily freeze and absorbs readily into leather.  Sulfating the Neatsfoot oil allows it to penetrate even further. 

Price of rawhide

The U.S.A. is only the eighth largest producer of leather in the world, with a total 669 million square feet produced in 2011.  The other top ranking leather producers superseding the U.S. that year were: China (3,913 M sq. ft), Brazil (1,832 M sq. ft.), Italy (1,573 M sq. ft.), Russia (1,460 M sq. ft.), India (1,397 M sq. ft.), South Korea (1,083 M sq. ft.) and Argentina with 715 million square feet of leather produced.

In the 1990’s the price of a wet nondescript cowhide in the U.S.A. was approaching $1.00 per square foot. Today’s price for a wet steer hide (over 53lbs.) from a slaughterhouse is about $70.00.  Because of its potential as leather, raw cowhide is generally more valuable than pig, sheep or goat hide.  However if the hair is to be retained then hair quality or unusual coloration like Angora goat or Holstein cow can fetch much higher prices.  There are authorities on this subject.

The price of meat influences the price of leather.  Tanneries must compete with food companies to get the hides because what is not converted to leather is immediately converted to gelatin instead.  Gelatin is made by boiling the collagen from skins, tendons, ligaments and bones in water.  Europe produces a large share of the world’s gelatin, supplying about 400,000 tonnes per year.  More pig skin is converted to gelatin than is cow, sheep or goat skin.  Gelatin itself is used in puddings, candies, marshmallows, ice creams, cakes, shampoos and miscellaneous cosmetics.

Removing the hide

 Flaying or “skinning” the hide usually takes one or more very sharp and slender knives.  These knifes generally dull quickly while skinning and need to be re-sharpened periodically.  The thickest skin on an animal is usually around the neck and shoulders.  The thinnest skin, which is more vulnerable to nicks by a skinning knife, is at the belly.   When removing the skin in one piece the starting incision is usually made from the chin, down through the center line of the belly, to the rectum.  From each foot, cuts running down the inside of the legs come down to meet the centerline.

Small the animals have thinner skins than large animals.  The most difficult skinning would have been preformed by a fur trapper that was compelled by market demands to tediously flay around the head, face and feet, or by a taxidermist who’s flaying gets even more intricate.  Furriers and taxidermist are rare these days but their profession still requires much more skill, patience and attention to the details of skinning than an average hunter would employ.

There is more than one way to skin a cat

Large industrialized slaughterhouses can remove a full grown steer’s hide in less than a minute.  Techniques differ but these factories usually employ moving assembly line division of labor or small teams working simultaneously on one carcass.  Skinners might use  pneumatic “roller skinners” or normal knives and a mechanized skin pulling apparatus.

factory skinner using a flaying knife

team using a hide puller

For small furs like rabbit and mink a commercial furrier might purchase or construct a hide pulling machine that quickly shucks the skin, leaving it inside out.  The only labor involved is making a few precise cuts beforehand, around the head and feet.

DIY Vegetable Leather Tanning

There are many, many books, pamphlets, magazine articles and YouTube videos detailing “do-it-yourself” tanning techniques.  The novice should focus on the overall intent of tanning and less upon one particular technique.  The intent is always to remove the natural water and fatty tissues from a skin and replace them with something else.  A novice should initially avoid tanning large hides and seek something smaller. The amount of labor required for a large hide (bigger than a deer or sheep) can quickly become discouraging or overwhelming for the un-initiated.  The first decision to be made is whether or not the hair should be removed.

Caustic lye, potash or lime would be normal choices for de-hairing solutions.  It is possible however to simply submerge and tie a deer hide perhaps in a cold mountain stream and leave it there for a week or two. Returning later one will find that the hair pulls out easily by hand, no caustic solution was needed.  Many sources are adamant that the first thing to do with a hide is to scrape the flesh from the underside.  Alternatively though other tanners might prefer soak a hide first, thereby loosening both hair from one side of the hide and softening those fatty flesh tissues from the other.  If the tanner of furrier decides to keep the hair then he skips the de-haring alkali bath and moves on to fleshing.

* Buffalo hunters in the past didn’t flesh their hides at all, but cured and preserved the hides for shipment by spreading on salt and drying them out in the sun.

The “Indians” native to North America were expert leather tanners.  Every bit of their clothing was made of leather and often their homes were as well.  For scraping the hide they used tools made of bone, rock, wood or antler.

Factories involved in vegetable tanning were also compelled to physically flesh the hide and they historically favored a fleshing knife and a beam.  The fleshing knife is simply a rather dull, flat strip of metal with two handles.  The beam was usually a short log angled from the workers waist, to the floor.  This provided a work surface that allowed the wet and heavy hide to be moved around easily, and provided a mechanical advantage by allowing the tanner to lean into the work with his weight.


Once properly fleshed, either a de-haired hide or a fur with all its hair intact will undergo essentially the same processes afterwards.  While tannin will stain things brown it may be desirable for de-haired hides but an alum solution might be chosen for hairy furs.  Small animal furs might need to soak in a tanning liquor for just a few days whereas large hides might need to soak for weeks.   The judgment call of whether a hide has set in a particular tanning liquor long enough or not, is made by cutting through a small piece of hide and examining it in cross section.  If the sample cross section is the same consistent color throughout then this part of the procedure is finished.  The hide is now tanned from a chemical perspective but much physical labor remains.  Any pinkish-ness or fluctuation in color from the edge to the center is an indication to soak the skin some more.

At this point, should the treated wet hide or fur be simply tossed out upon the ground to dry, it would shrink, curl and stiffen into a very unusable product.  To get the strong but flexible leather we are familiar with that hide needs to be washed, rinsed, twisted or rung out like a towel and then thoroughly tortured as it dries.  A half dried skin can be laid over a tree stump and using a soft mallet, pounded over every square inch of its surface with short glancing blows .  At some point before all the moisture is gone, the leather is oiled.  It is this tedious but important, continual stretching, pounding and working of the skin as it dries, that produces flexible leather.

   Un-tanned rawhide can be preserved by drying it out.  If it is not to be tasked with some immediate purpose like being stretched over a hollowed out log to make a drum, then it can be saved for proper tanning at a later date.  Some rawhide might exist in a transition state, being only partially tanned.  Stretching a hide on a frame, or tacking one to a barn wall are popular methods of drying skins out.  Residual bits of fat or flesh can be scraped at leisure, either the suede or epidermis side can be attended to and once it’s flat & stiff the dried rawhide can be stored inside.

The novice or independent furrier has many options to improve his fur.   Furs can be washed in dish-washing detergent to remove oils and odor.  Vinegar and salt solution can be used to “pickle” the skin which helps “set” or lock in the hair.  The pickling solution is usually neutralized with baking soda before the fur hits the alum bath.  Once dry after the tanning bath, a fur might be rinsed in gasoline or naphtha (white gas used in camp stoves and lanterns) to remove any lingering oils or odor.  [Dry cleaners predominately used naphtha or another flammable petroleum fraction before 1911].  The flesh side of the fur might be sanded with sandpaper to remove high spots, making the suede uniform and level.  When finishing a fur it might be brightened by tumbling it in cornmeal, bran or sawdust which is then combed or brushed away.

Individual tanners working with a hairless hide might consider smoking it over a fire.  Some American Indian tribes once made the majority of their clothing from smoked deer hides.  After being fleshed, de-haired, cured in a bath of boiled tree bark tannin, worked to pliability and bathed in fat or brain oils, a deer hide was commonly draped over fire.  Being supported by a little tent like frame of green tree boughs the hide was rotated occasionally, collecting preservative chemicals and additional color along the way.

Once again, there are many sources and even videos of this topic available in the library or on the Internet.  Some of these sources have excellent information others do not.  The reader should be aware of several alternative vegetable tanning methods or recipes before religiously adhering to just one.

Other leather

   There are some schools that teach tanning and/or taxidermy and colleges or universities that offer chrome and aldehyde tanning curriculum.  There are products that disguise the origin of leather and some new organic products for vegans that imitate leather.  Often commercial leather is split, yielding at the least two different products; a “top grain” and one or more layers referred to as “split hide”.

Patent leather has a shiny, glossy finish and gets its name from a finishing and polishing process that was patented some two hundred years ago.  A satisfactory substitution or duplication of that process can be created by painting leather with layers of pigmented linseed oil (similar to oil painting on a sheet of canvas) and then with layers of varnish or lacquer.  Modern patent leathers (not vinyl or poromeric imitation leathers) usually have plastic coatings.

An “aniline dyed” leather refers to a very high quality ‘top grain’ leather that has been dyed clear through with a soluble dye.  A hide’s entire natural surface with pores and imperfections is visible with aniline dyed leather. No sealer, paint or insoluble dyes were used.  Should imperfections like scratches, blemishes or scars be sanded or disguised then the improved leather is referred to as “semi-aniline” dyed.  Most leather car upholstery is “pigmented” leather, meaning“semi-aniline” dyed leather with a heavy durable, protective, pigmented polymer surface coating.   Aniline is also a precursor used in the manufacture of polyurethane.

The Chinese were known to have boiled leather to make armor.  Probably many cultures over the centuries used leather armor but few if any examples exist in the historical record because they would simply biodegrade.   There might have been a lot of boiled leather armor back in medieval times but no one knows for sure now.  Boiling leather makes it shrink, thicken and harden.  Boiled in water or perhaps oil or tallow, the leather becomes mold-able for a short time and will freeze or set into shape as it dries. Overcooking makes it brittle and likely to shatter.  This site discusses making leather armor.

Authentic cheetah, giraffe, tiger and zebra hides are rare now but they were once fairly common.  Some leather producing outfits have taken to printing the hair of cow hides with ink, in patterns resembling these animals.   Even the hides of Holstein cows might be suspect.

As long as people continue to eat meat, there will be a continual supply of animal skins.  The rate of human population expansion is unsustainable and as a species we are soon to eat ourselves off this planet.  Nonetheless some vegans and or members of PETA (People for the Ethical Treatment of Animals) would have us believe that many animals are raised and slaughtered solely for the leather.  Aiming squarely for this demographic, companies like MuSkin, Myx and Mycoworks are actually growing, convincing leather substitutes by using mushrooms.   A substrate, matrix or mat of linen or hemp fibers actually gives this artificial leather its integrity and strength.  In essence either the chitin from the cap or the mushroom mycelium itself fills the spaces between mat fibers.   Apparently incubation and manipulation of fungus while growing can be controlled to a point where zippers can be incorporated without sewing.   Apparently members from the gilled Pleurotus genus and the non gilled Phellinus genus of woody mushrooms are producing the best mushroom leather  <images> or <other images>  results.

MISC informative LINKS

Some chemicals used in leather processing


Hemlock history in New York

Buffalo destruction / global market

Ethnobotany of tannins

Leather furniture facts

World Statistical Compendium for raw hides and skins, leather and leather footwear 1993-2012   <PDF>



Curing & Preserving meat



Although potentially a messy and inconvenient chore, the ability to procure one’s own food by slaughtering an animal is an essential skill for the well rounded and self sufficient individual.   This post offers some brief suggestions on how to butcher and process meat properly.  If fresh meat is not to be cooked and consumed immediately, there are some time honored meat preservation methods to choose from.  Jerking (drying), canning or salt curing & smoking methods easily come to mind.  Freezing may have become the most convenient way to preserve meats since WWII but these will still begin to deteriorate in other ways if they are left in a freezer too long.  Frozen meats are also dependent upon continuous uninterrupted sources of electricity.

Processing, curing and preservation methods may differ between animal species.  Raw fish for example, which begins to deteriorate very quickly can still be canned, smoked or turned to jerky.   The precautions for fish preservation differ by being more urgent.  Traditionally larger animals were butchered only when the climatic temperature dropped to levels that retarded meat deterioration.   It is no mystery why today’s deer, elk or moose hunting seasons begin in the fall.  When butchering large to medium animals like cattle, deer, sheep, goats or pigs, the first significant priority is to reduce the carcass’s internal heat.  The best way to do that is to bleed it, remove the skin and split the carcass.   There are probably as many detrimental fungi and bacteria lurking inside the meat as there are outside it.  The quick reduction of internal body heat in a carcass is the first step in reducing undesirable microbial or enzymatic deterioration of meat.  Snow banks and cold concrete floors can act as desirable surfaces in this heat reduction endeavor.

pre - 1911 "Reefer car" / Wikimedia commons

pre – 1911 “Reefer car” / Wikimedia commons


 In modern industrialized nations, refrigeration has changed our diet and has permitted the manifestation of the modern supermarket.  In urban areas, before refrigeration came along, fresh meat could be immediately consumed by a large populace, before it had a chance to spoil.  Before refrigeration and outside urban areas, meat harvesting was traditionally preformed in the fall or winter.  Cold temperatures assist in processing and preserving meat by discouraging bacterial activity both inside and out.  A century ago the availability (or not) of fresh meat and vegetables was dictated by seasonal and climatic temperature.   Initially commercial meat processors and brewers relied upon refrigeration from wintertime ice blocks cut from lakes and stored in sheds.  Properly ice ventilated “refers” or refrigerated railroad boxcars began shipping meat, dairy, vegetables and beer around the U.S. in the 1880’s.

US National Archives image /1917-18

US National Archives image /1917-18

Although invented a few decades before on both sides of the Atlantic Ocean, artificial refrigeration did not find successful application in the meat packing industry until the turn of the century and its accompanying delivery of commercial electrical power.  By 1914 artificial refrigeration was the norm for perishable food wholesalers and retailers.  Like milk or newspapers arriving on the doorstep, ice blocks were delivered to the ‘iceboxes’ of most urban homes.   In the 1930s, newfangled electrically powered household refrigerators appeared, but since coinciding with the ‘Great Depression’  – only the affluent could afford them.  Rural areas would wait much longer for delivery of electrical power.   After WWII, household refrigerators finally became common for the rest of the nation.

No longer restricted by the seasons, today we can buy fruits or vegetables “out of season” because they are maintained in a chilled state while being shipped from far away.  Likewise, supermarkets and groceries presently offer us plentiful supplies of fresh cut meats; due to the marvels of electricity, artificial refrigeration, and oil dependent transportation supply chains.


 Curing– can be a vague term because it is a process where so many ingredients or methods used can apply.  The only essential ingredient in a cure is salt (plain NaCl / without iodine).  Salt draws moisture out of the meat and it shuts down most microbial activity.   Although humans like other animals require salt in their diet, and at moderate levels it may enhance taste; salt has actually been such a historically valuable trade commodity because of its capacity to preserve meat.  “Corning” is the process of treating raw meat to dry salt crystals (any type of salt:  pickling, rock, kosher, dairy or canning – but not iodized which may cause discoloration).  There are quick acting “dry” cures where salt crystals and perhaps additional dry spices are packed directly around the meat.  “Wet” cures are essentially brine solutions in which meat is submerged and soaked.  In either case salt causes water to be drawn out of both muscle tissue and out of undesirable microbes by osmosis.  “Pickling” meat generally refers to using a curing mix or solution that also contains sugar and extra spices.  Sugar or honey might be included in a cure to counteract the harshness of excessive salt and to keep meat moist and tender.  Some spice combinations don’t work – garlic and black pepper can overpower a cure.   A “hard cure” implies a process involving both salt curing and long term exposure to preserving pyroligneous acid from creosote in wood smoke.   A hard cured ham or slab of bacon can become very dehydrated over time.  “Ageing” is a term usually reserved for beef.  Quality, tender “premium” beef is sometimes “dry aged” and is usually only to be encountered in a good restaurant.  The general public can only purchase a compromised product from the grocery, referred to as “wet aged” beef.

   Jerky” is an Anglicized version of a previously Spainglacized (?) version of a original Incan word: “ch’arki” – meaning dried meat.  Although any meat can be “jerked”, venison and lean beef respond best to the process.   Obviously low air humidity is necessary for the process.  For simplicities sake the raw meat can be dressed into the form of large and wide, but thin slabs before being introduced to the cure.  Either a dry salt cure or wet brine solution should be applied to the meat.  Afterwards the individual slabs are cut into thin strips and spread on a rack.  Whither exposed to sunshine or spread on racks inside, the meat should dry enough eventually, to snap rather than fold when it is bent.   A dry cure might produce results more immediately, because a brine-cured meat might soak in solution for a 3-6 day period before being removed for drying.  Below is an example brine recipe that might as easily be applied to a ham as it is to jerky.



Naturally, meat can be canned at home.  This post won’t delve very far into the details of canning but the main thing to remember is that any improperly canned foods are subject to developing botulism.  Clostridium botulinum is a curious, heat resistant bacterium that despises oxygen.   So while a host of bacteria like salmonella, E.coli, and listeria monocytogenes are killed at boiling water temperatures (100 deg C / 212 deg F),  botulinum spores locked within an airtight can, bottle or glass jar – would not be killed.   To insure canned food is safe, home canners must maintain an elevated temperature for an extended time.  By using a large specialized pressure cooker known as a “pressure canner”, the cook is able to reach an abnormal 115.5 deg C / (240 deg F) temperature by essentially doubling the atmospheric pressure first.   To be safe, that high temperature is maintained an hour to an hour and a half.


The Carib Indians were smoking fish over fires to drive flies from drying fish jerky when Christopher Columbus discovered these “Indians” in the New World.  Almost every type of fish responds well to curing and smoking but fish with a high percentage of oil (greater than 5%) do not air dry well.  Oily or fatty fish that do not dry properly are often preserved by “corning” instead.  Three to four generations ago many people in coastal regions continued to salt pack fish away in wooden barrels in the same way others inland might have stored “pork butts” or bacon away in barrels.   Requiring no refrigeration, freshly cleaned and dressed fish were sprinkled with corning salt and then stacked in a keg.   After about four days the salt pulls enough moisture from the fish to create its own brine solution.   Then the fish are rotated and re-stacked in the barrel, more salt and fresh water are added until the brine solution covers all the fish.  The fish should be firm when the salt has completely penetrated through the flesh.  Before consumption, the excess salt is washed and rinsed away, and fish are soaked and refrigerated in fresh water overnight.

* In the Great Lakes region people have occasionally contracted ‘broad fish tapeworm’ – from eating uncooked pickled pike, walleye or other predatory type lake fish.  Freezing the fish before pickling eliminates this threat (as does cooking).

Fermented Fish

Several cultures have resorted to fermentation as a method of fish meat preservation.   In the Mediterranean, anchovies are allowed to ripen for at least one half of a year before they are considered ready.   Orientals might ferment anchovies, shellfish, squid or shrimp for more than a year to create that dark brown “fish sauce” they cook with.  Scandinavians might eat “Hákarl”, “Surströmming” or “Rakfisk” which are so odorous as to send normal people into flight.  Eskimos not only ferment fish but might toss birds, sea lions, walrus, whale parts or anything else with protein into the same earth covered fermentation pit.   Fish fermentation works because most bacterial activity is halted as the level of acidity increases.


The same preserving techniques used for other meats can also be used on fowl.   Since fowl seems to dry rather quickly, brine curing solutions are preferred to dry ones.   Turkeys and chickens are seldom hard cured (smoked) whereas ducks and geese can be because of their higher fat content.


Driving out excess moisture from meat deprives bacteria and fungus a furtive environment to grow.  While salt cured pork hams and bacons may hang for years in a smokehouse, the primary purpose of a salt cure and of smoke is to dehydrate and preserve.  Only cheaper cuts of beef from the chuck, rump or brisket are improved by salt cure and smoke preservation.   Cures for beef will still employ salt, but are also sweetened usually with something like brown sugar, maple syrup, molasses or honey.

Pastrami, corned beef and ‘bully beef’ are salt cured and packaged or canned without being smoked.  Beef being a larger animal, has about twice the number of basic or primal cuts as does pork.  There is little agreement or standardization between cultures or countries on how a beef should be cut.  Thanks to refrigeration, beef can be deliberately aged to improve its character, but pork is seldom treated more than a couple of days this fashion.

Unless you go to some effort, the only way an individual is likely to encounter aged beef is to order it in a good restaurant.  The public has no access to properly aged beef in a grocery or supermarket.  Today meatpackers just inject the beef riding conveyor belts, with chemicals like sodium phosphate- which changes the pH of meat protein and allows it to hold more water and weigh more.  “Still wiggling” so to speak, the wet and fresh steak or what have you undergoes treatment with other chemicals, gasses and perhaps radiation, before it is hermetically sealed in shrink wrap and crated for shipment.  While in transport to a retailer, this commercial beef with which we are acquainted is euphemistically referred to as “wet aged” beef.


chopped from U.S. Department of Agriculture poster

Dry aged” beef on the other hand is where a side of beef hangs in a refrigerated meat locker for many weeks as it tenderizes.  The meat locker is maintained just above freezing (34 – 40 deg F), allowing oxidization of fats and enzymatic breakdown of muscle proteins to occur.  Meanwhile gravity pulling upon a side of beef is considered to assist in fiber tenderization.  Only superior beef carcasses with good marbling (streaks of fat interlaced throughout the meat) are subjected to the expense of dry aging.  Dry aging allows time & environment for enzymes to break down muscle proteins into shorter fragments.    Exposed to free air, fat oxidizes and adds flavor to the meat.  Since the process requires extra time, storage space, electrical refrigeration and causes a split carcass to loose a good deal of weight through dehydration –aged prime beef cuts are uncommon and expensive.

Processing Pork

Pigs are very efficient animals to farm for slaughter because the majority (>87%) of their weight is converted to food.  A pig’s skin is often converted to food whereas a cow’s skin is not.  Pork lends itself better to salt curing preservation than does beef or large, lean wild game.  On the American frontier the hog was a cost-effective animal that was almost indispensable to early settlers.  Pigs thrive in most climates, eat almost anything and reproduce quickly.  With just a few pigs, farmers could feed their families through the winter, sell some or stash some extra meat away in storage and still have lard leftover to make things like candles or soap.  (* For candles, alum & saltpeter were added to harden tallow.)

* Noting the Jewish and Islamic taboos on eating pork, the restrictions probably made perfect sense to earlier civilizations in the warm Middle East.  Pigs can carry several types of parasites or viruses.  Trichinosis comes to mind but this encysted larva of a parasitic roundworm might be found in almost any type of wild mammal also.  Omnivorous pigs do have a more basic and quicker acting digestive system than do cattle (or humans), and they have no sweat glands to expel pollutants they might have ingested Pork is one meat that definitely should be cooked well.  That means reaching 71° C (160°F) temperature down deep next to the bone in a piece of meat.  From New Guinea to Hawaii the ancient Polynesians cooked pork in a pit; usually to a point where the meat just fell away from the bones.


People who raise pigs for easy slaughter might prefer their shoats to be of manageable scalding size – say 45kg (100 lbs.) or so.   Immediately after killing a pig, “sticking the pig” refers to puncturing its carotid artery with a knife to let the blood run out quickly.  Since retaining the skin is often desired, the easiest way to remove the hog’s hair is probably to scald the carcass in boiling water.   Next the hair should be scraped off with a blunt edge tool similar in sharpness to the backside of a butcher knife.  Afterwards flame can be used to burn off any remaining individual hairs.   Actually surrounding a pig’s carcass with dry straw and setting the pyre afire is an ancient alternative to hair removal by scalding.

After scraping, the pig’s carcass is often hauled up into a tree by its separated hind legs.  This allows the blood and other fluids to drain, allows for easy separation of the offal and facilitates simple splitting of the carcass down its backbone.   Splitting down or through or beside the hard vertebra requires a tool like a hacksaw, reciprocating saw or heavy butcher’s  (not a flimsy Oriental type) meat cleaver.


* Butchering can be preformed on a flat table also.  The following link to a video shows a skilled butcher doing just that.   Whole Pig Butchered Video

*Another video showing where bacon is located and how it is cut.

After being processed to the point of being split into halves or smaller “primal cuts” there are several avenues to take:  as in choosing between barbecuing, canning, freezing, etc.  This post is concerned with exploring the old fashioned smoke & salt cure methods of  long term preservation.  The majority of traditional curing recipes were intended to complement pork coincidentally.

Typically a ham or shoulder might be packed in dry salt cure (1 lb. for every 12 lbs. meat) and remain that way for at least (2 days per lb. of meat).  The same cut would remain submerged for about twice that long for a brine cure – or a month max.  Thinner bacon or loin cuts would differ by requiring about half as much salt cure.

For the thick ham and shoulder cuts a “brine pump” is very useful in preventing rot, by injecting cure solution down deep next to the bones.   Length of smoking period is a matter of taste, with 4 days being a minimum and no limit on a maximum exposure.   Virginia hams, already cured, might yet hang in a smokehouse for years.  Back in Colonial American days these hams were valuable and articles sometimes needing protection from theft.


* “Boston Butts” or cuts of pork do not come from the rear end of a hog – just the opposite.   The name comes from colonial America and the way that these tender shoulder cuts were packed for export and in salt, within smallish or middling sized wooden kegs (the cask themselves were referred to as butts).  

Usually an experienced butcher will separate the loin and belly sections from the shoulder (top butt and picnic) section by cutting down between the 5th and 6th ribs.   Ribs are counted, beginning from the neck.  The loin region ends at the last rib.  The tenderest meat from either a pig or a cow comes from the tenderloin.  The tenderloin is a long muscle that doesn’t get much use, and it runs inside the rib cage and alongside the spinal column.   The “Filet mignon” cut steak comes from the smaller end of this muscle (the end further away from the hip).  The expression “Living High on the Hog” refers to eating or being able to afford the most tender and therefore most expensive cuts of meat.   As with cattle or any similar herbivore, meat generally gets tenderer as the distance from the hoof grows.


hash of 4 altered public domain images


Horses normally have 18 pairs of ribs, but occasionally 19 pairs.  The first eight pair of horse ribs are “true ribs” and the other ten are “floating ribs”.  Pigs have 15 to 16 pairs of ribs – depending upon breed.  For comparison humans generally feature seven “true” plus five “false” ribs, for a total of 12 rib pairs; except for an occasional human who may possess a pair less or a pair more than normal.  Cattle have 13 pairs of ribs.  “Chuck” cuts of meat come from the area surrounding the first five ribs on a side of beef.  In the U.S., “Rib” cuts of beef come from the area between rib #6 and rib #12.   The last or 13th rib marks the beginning of the loin region.



The bits and scraps of meat and fat left over after butchering are not wasted but put into sausage.   Traditionally the small intestines of the animal in question were washed carefully and stored in brine until used as the casings for stuffing.   Cleaning intestines is a tedious job as both sides have to be carefully scraped of fat and mucus.  Everything must be rinsed several times.   Someone today might opt to purchase artificial casings or perhaps purchase real hog or sheep casings on-line or from a butcher.

Any type of meat can be used alone or in combination to make sausage.  The happy balance between meat and suet in sausage seems to be somewhere around 2 parts lean meat to 1 part fat.  Too much fat makes a greasy sausage that shrinks, while too little makes hard and dry sausage.  Sausages can be hard cured and preserved for long periods, eaten immediately or frozen.  Seasonings to avoid if freezing sausages would be garlic, sage and salt.  Somehow the freezer makes the garlic tasteless and causes the other two to produce bad taste.

Besides casings the only other item needed to make sausage is a machine to grind up the meat.   Food processors can perform this function but leave the particles too small.   Expensive electric meat grinders perform admirably but are overkill for the occasional homespun sausage maker.  The ideal sausage grinder for occasional use might be a hand cranked model, invented over a century ago.   Smaller black & white reproductions of this approximately 117 year old poster below were probably placed in mail order catalogs.  A  funnel shaped attachment for stuffing casings accompanied the product.   Copies or clones of this chopper are still being manufactured today.


Disease, toxins, worms and other nasties

Toxins or “biotoxins” are the poisons created only by living cells or organisms (all other poisons are correctly referred to as toxicants).  Some pathogenic viruses, bacteria or fungi may require oxygen, while others do not.  Acidity or the lack of, radiation like x-rays or UV light, freezing temperatures or high cooking temperatures and chemicals like salts, can all deter the detrimental effect of biotoxins in food.  There are at least two hundred different known diseases or maladies, transmitted through food to worry about.  Only a few short descriptions are listed here…

Clostridium botulinum which is responsible for botulism, is killed or inhibited by saltpeter (NaNO3 or KNO3), oxygen and high cooking temperatures. The most lethal neurotoxin ever discovered by mankind is named after a Latin word meaning – sausage.  “Sausage poisoning” was once more common than it is now.  A can of improperly cooked peaches may produce botulinum toxin.    Although it can kill quickly, contracting botulism these days is very rare, something like 10 cases a year in the U.S.   <see Alaskan Eskimos>   The bacterium is found throughout the world in the soil and in untreated water.  Some vain people actually pay a cosmetic dermatologist to inject this deadly protein into their face <see Botox> , where it has the effect of weakening or paralyzing facial muscles and removes wrinkles.  The toxins created by this bacteria are inactivated by cooking to 160 deg. F.   The bacteria itself is killed by 175 deg. F temperature but the dormant spores themselves won’t be killed until 250 deg. F is reached.

Salmonella is caused by eating food contaminated with animal feces.

Campylobacter jejuni is the most common cause of bacterial foodborne illness in the United States.

Listeria or Listeriosis is caused by the Listeria monocytogenes bacteria  and is the third-leading cause of death among foodborne bacterial pathogens.

Escherichia coli (E. coli) are bacteria that live in human and animal intestines.

Trichinosis is a fairly rare (now) parasitic roundworm disease, caused by eating undercooked meat containing the worm’s  larva.  New strains of this parasite have been discovered that are found even in birds and crocodiles.

Toxoplasma gondii is a parasite that is the second leading cause of deaths attributed to foodborne illness in the United States.  It is one of the more common parasites in the world and affects about 1/3rd of the human population.   The parasite goes to the brain and forms cysts.  Laboratory rats affected by toxoplasma gondii loose their innate fear of cat urine odor and the males begin to produce more testosterone.

Hepatitis E is a liver disease caused by a virus transmitted by fecal contamination in water or food supplies.

Chemical Additives

Without food science and the shortcuts taken by Big Food and Big Pharma corporations, we could not sustain our present standard of living, nor feed ourselves- our masses as we do.   Not too long ago, almost all edible foods came from farms.  Today’s food however is largely produced in factories.  This processed factory food is chock full of questionable chemicals and additives.  Be assured that most of these additives are safe from a chemist’s perspective.  Intermittently however, new research uncovers dangers and unintended consequences associated with ingestion of these ‘safe’ food additives.

Sodium phosphate commonly encountered as approved STP (Sodium Tripolyphosphate) allows meat to hold more water.  This is good for the seller who pumps this stuff into meat and bad for the buyer who must purchase meat by weight.  To be fair, phosphates do help extend the shelf life of meat and dairy products like cheese by restricting the development of rancidity.  Phosphates are under suspicion however of increasing the risk of kidney disease, high blood pressure and heart disease.

Sodium Lactate also increases meat shelf life and can be expected to benefit color and taste.

Sodium Erythorbate, Erythorbic Acid and Sodium Isoascorbate are added to meat to preserve its color.   Keeping meat pink is a big thing; carbon monoxide gas is also used for this purpose as were sodium or potassium nitrites before the 1970’s.

Monosodium Glutamate (MSG) is an amino acid that makes meat and other food taste better.   It allows companies to perhaps put less real meat into packaged food.   Irregardless to brain damage caused to mice, baby- food makers of the 1960s put MSG into those little jars to influence the taste buds of parents.

Potassium Sorbate and Sorbic Acid inhibit mold growth on jerky, sausages, cheese, syrup & jelly.

Sodium Citrate which is a crystalline salt derived from citric acid fermentation or by the neutralization of citric acid with sodium hydroxide.  It’s been recently approved for use in meat products as a preservative where it slows spoilage from microorganisms.  Salty and tart in taste – it maybe used to flavor soft drinks and juices or be employed as an emulsifier.

Hydrolyzed vegetable proteins are used as Meat Flavor Intensifiers (MFI)  and boost or increase the meaty flavor of meat items, gravies, and sauces.

Ractopamine hydrochlorid  is not a chemical added to meat.  Rather it is a growth enhancer, fed to livestock, which increases profits by requiring less feed.  Quickly grown cattle fed this growth enhancer develop lean meat.  Chickens and turkeys fed stuff like this often develop over-sized hearts, kidneys and livers, and grow so fast and get so heavy that they become immobile and cannot carry their own weight.  Cattle and pigs fed a diet of ractopamine have developed abnormal lameness, bloat, breathing disorders and hoof disorders.   Approved in countries like the U.S., Canada, Mexico, Japan and S. Korea – ractopamine hydrochlorid enhanced meats are outlawed in the EU, China and Russia.

Transglutaminase (TG or TGase) is an enzyme that bonds protein molecules together.   First identified in 1959, it took another 30 years to find an economical source and exploit this ‘meat glue’.  “With meat glue you can glue any protein to any protein”.  “Gluing chicken skin to salmon works quite well….. and will actually protect the outside of the salmon from overcooking”.  <Frankensteined meat> 

Saltpeter can refer to several separate substances, most of which were strategic materials for making propellants and explosives in the 18th & 19th centuries.   Sodium nitrate (NaNO3) is the compound most usually identified as a meat preservative, but also potassium nitrate and magnesium nitrate to lesser degrees.   While regular table salt (NaCl) kills many bacteria like salmonella below 3% solution, much higher concentrations might be needed needed to kill other types of bacteria.   A concentration of about 20% salt soaked into meat would be required to make meat safe from most every type of microbe.   Meat that salty is not palatable.  Somewhere back in time before the Romans, people noted that salt from certain mines preserved meat better, retained its color and made it taste better.  Eventually traces of nitrate (saltpeter) were identified within that or those popular mined salt(s).  The nefarious Clostridium botulinum bacterium was identified in 1895.  Thereabouts it was determined that nitrate salts kill or inhibit the botulism causing bacteria.  Since saltpeter also benefits color retention and imparts a desirable flavor we have been using nitrate meat preservatives every since; up until the 1999 that is.

The U.S. FDA has determined that nitrates are no longer allowed in commercially packed meats, while nitrites are to a limited small degree (for dry cured uncooked products like jerky).  Nitrates and nitrites differ by one oxygen atom.  Ammonia is released into the soil by the decomposition of organic matter, and it oxidizes to form a nitrate or nitrite.    Nitrates themselves are relatively inert and enzymes in the human body convert them into nitrites anyway.  Some vegetables we eat daily are loaded with nitrates, containing far more nitrates that might be encountered in cured meats.  Some athletes might drink nitrate rich beet juice to enhance physical performance.   Nitrites can turn into useful nitrous oxide by losing an oxygen atom or into dangerous nitrosamines, which can be created by high heat cooking.  In the 1970s several studies showed correlations between nitrosamines and cancer in rats.  Since that time, nitrates in curing salts have been studied to an exhaustive degree.  The verdict is that nitrates and nitrites are not carcinogenic.  Apparently nitrosamine formation can be inhibited by ascorbic acid.  Since refrigeration is fairly ever-present today, there no sense in risking the possibility of someone creating nitrosamines by overcooking -uncooked nitrate cured meat.   Individuals wishing to hard cure meat by traditional means can still buy premixed ‘salt cures’ containing either nitrites or nitrates or both.   “Prague powder” is one such cure that is still sold after being invented 80 years ago.

USDA Ham and Food Saftey information.


There are two widely separated forms of meat smoking.   The old way of smoking for long term preservation – is now referred to as “cold smoking”.   The new and widely spreading fad or form of meat smoking encountered these days is called “hot smoking”.

Hot smoking implies drenching meat in humid, flavorful smoke while simultaneously cooking the meat.   Temperatures between 130 and 210 deg F are required for hot smoking.  Since the cheaper and relatively tough cuts of meat are used in this process, the cooking is done slowly; taking a long time under moist heat to breakdown and soften the cartilage or gristle (collagen).    Done correctly those tough cuts become very tender to chew.   Hardwoods like oak, hickory, apple and cherry produce the most flavorful smoke.   Depending upon the fuel used to create cooking heat (wood fire, propane, gas, electric) the smoke might be generated by pellets or moistened wood chips.   Hot smoking is purely concerned with the art and science of cooking delicious, flavorful meat.   It does not impart a preservative effect upon the meat.

Cold smoking has been going on for thousands of years, and for more practical reasons too when considering the historical lack of refrigeration.   Wood smoke imparts preservative creosote to the meat that discourages insects and microorganisms alike.  Wood smoke flavor in an aged hard cured ham or bacon might be intense, but still of a secondary nature when compared to the typical saltiness of that same dehydrated meat.   “Virginia hams” were and still are famous for their flavor but these are often so salty that they need to be soaked and rinsed for 3 days to get the salt out.

Speaking of Virginia hams, Martha Washington (wife of the first American president) was famous for hers.  The plantation at Mount Vernon was typical for plantations of the period.   In addition to a large number of working residents to feed daily, guest and foreign dignitaries were always dropping in for visits.   Martha reportedly set a good table.  She also took pride in her hams, oversaw their curing process and shipped many away as gifts, some across the ocean.   Two hundred years ago working plantations like this had crews to maintain large continually smoking smokehouses, which were packed with beef, pork, mutton, ducks, geese, fish and anything else they could find.

Famous uncooked, hard cured, smoked Virginia hams are available for purchase.   These and some others like them are intended to be cooked, however some even more prominent European hard cured hams are usually eaten raw and are still allowed to be imported to the U.S.  (Ardennes Ham from Belgium, Jamon Iberico & Jamon Serrano from Spain, Prosciutto from Italy,  Westphalian Ham from Germany and sometimes York Ham from England – for example).


I am neither a chemist, physician nor an authority on the safety of consuming uncooked meats.   All I can do is observe and realize that decisions made while preserving meat in traditional ways, do carry some risk and should not be made lightly.

Somehow this particular post took a detour and became somewhat longish.   The title will be truncated from “Curing meats & Tanning hides” to what you see now.   The last image from the post preceding this one featured a tiny homemade cold smoking apparatus featuring a venturi.  The background of that fabricated image features a (lost) drawing of an industrial smokehouse, the type of which might have been found in any city of size, before artificial refrigeration was realized.   Wood smoke was also used to preserve leather, a trick American ‘Indians’ were fond of.  Rawhide and leather though, are fodder for a future post