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Better Leaving Through Cow Pee, or... Chemistry

Painting has evolved over time. The collective ‘we’ have discovered that paintings are not some static inert decoration but they are living, breathing, and at least changing over time things. Art has transformed over time, too, from cave walls to the sides of buildings, but that is not what I’m talking about, or is it? More on cave walls later.

Paint it seems (pigment), like everything else, is basically chemistry (elements, molecules, electrons), maybe it’s really just physics (energy). My sister once told me that at some level it’s all the same (math, chemistry, and physics). I tried studying all three and failed miserably... took up painting. Can you see where this is going?

Pigments are made from minerals and chemical molecules, some derived synthetically after about 1850. That was not always the case, though, as paints and their traditional oil medium have been made not only from ground up rocks, but from organic living things... plants, animals, insects, even humans (yup, mummy brown). Vermillion from insect exoskeleton, Indian Yellow from dehydrated cow pee by way of cows fed only mango leaves.

Some paints never dried (bitumen or asphaltum), some changed color from green to black (fugitive color, I believe it’s called), many are toxic, and some are even lethal like copper arsenic green wallpapers in Victorian England. I mean we know not to eat lead paint or breath powdered pigments. Wash your hands, “wear the damn mask” (Gov. Hogan) sort of thing. Today we have all manner of knowledge... X-ray vision and spectral chromatography, basically we know the chemical composition of those rocks... like lapis lazuli and sapphires vs. emeralds. We know they contain metal. Metal ions... it is geology not rock(et) science.

Linseed oil made from flax seed mixed with colorful metal compounds and smeared on linen made from flax plants stretched over a wooden frame and tacked down with tiny nails called brads or tacks is ‘oil painting.’ It forms a very flexible and strong system, except when it doesn’t. And today we know why it doesn’t, but we continue to eek along making minor adjustments trying to improve on it.... drum roll... like acrylic paint.

The thing is oil paintings don’t dry, per se, they oxidize. Now this post is not about eye glazing chemistry... more the zen of motorcycle maintenance... metal meets oil (fat)... cross linking, polymerization... dry paint. Only it doesn’t stop there. Those dried oils change over time, the glycerin backbone releases those fat molecules. Those metals that make up pigments... the metal ions moooove. Like trying to paint cows. It seems that some metals are better than others at keeping their pants on. Two in particular Aluminum and Zinc have misbehaved badly and paintings have fallen off the canvas. There are metal soaps forming and oozing out of the surface of paintings that are 400 years old. It’s really quite ephemeral. Conservators are at a loss how to stop it or even reverse it.

One of the issues is canvas.... it rots, it molds, bugs eat it, it absorbs moisture, changes in temperature and humidity swings cause it to expand and contract, and that’s just to name a few of the issues. Paint cracks, steel tacks rust (thus monel and stainless steel tacks), wood frames embrittle and dry rot. Why bother? That’s a really good question but we do bother, so what is possible?

State of the art, painting best practices change over time as we think we get smarter... sometimes we go full circle and realize that the anti fouling bottom paint for boats is killing the fish for which we desire to sail in the first place. I mean who knew barnacles wouldn’t like the taste of the most toxic and hormone disrupting chemicals ever made by mankind? Other times artists are just stubborn... like ‘hey, I like using house paint for my art’ (yes, it happens). Manufacturers are some of the most, profit motivated, worst culprits (zinc comes to mind). Sometimes we just notice that a pigment is not lightfast and stop using it (alizarin crimson).

Here, I thought I would just paint, after all, people have done it for millennia, and then, after 20 years of painting, I discover I was doing it all wrong, that I was naive, uninformed and hoodwinked by art supply manufacturers, yuk yuk! Not funny. Sometimes we figure it out 600 years later.

Harrison’s Nocturne (1996) acrylic on canvas

This is what I have learned... we (collective) started out using red mud and fat to make cave paintings (60K BC), then wood panels, then metal panels, then papyrus, hemp, linen, cotton, fiberglass, polyester, and now carbon fiber canvas... and now we are at composite wood or metal panels again. Full circle... and throw out or environmentally soundly dispose of your zinc white paint, buy lead white paint while it’s still legal, don’t eat your paint, and wash your hands, wear a respirator if you mix dry powdered pigments, and when sanding oil grounds... oh and your painting will still self destruct after 1000 years or much less time unless, of course, red colored mud (iron) and fat on rock cave walls (you read it here first). And always remember, painting is fun and easy!


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