The Ecology of Color

The Ecology of Color

Posted: December 28, 2023

Have you ever thought about where colors come from? When you look at a selection of nail polish in a salon, peruse a rack of paint chips at a hardware store, or see a set of art supplies, do you ever wonder how we found all of those colors in the first place? How did we harness color for our use? How did we get color recipes for unique shades? It might not be everyone’s particular curiosity, but it is definitely one of mine.

Some of the first pigments used by humans are ‘earth pigments’, colored clay deposits in the earth known as ochres in shades of red, brown, and yellow. The early palette also consisted of white chalk and charcoal or soot collected from burning wood and animal fats. The Lascaux Cave Paintings are a great example of what can be done with this limited natural palette. In addition to minerals, plants are a source of a vast variety of pigment and dyes. Plants contain color pigment cells: chlorophyll, carotenoids, and anthocyanins. Chlorophyll as many of us may know is what makes plants green. Many of us may even know that the leaves changing in the fall is due to the chlorophyll no longer being produced by the plant, revealing the other pigment cells underneath. It is the lesser known carotenoids that are responsible for our red, yellow, and orange autumns while anthocyanins produce deep reds and blues. Anthocyanins are also often PH reactive. Most famously this is seen in litmus paper, derived from lichens, a visual PH indicator turning red or blue depending on the PH of a solution, a.k.a. anthocyanins at work.

Humans have used this reactivity to expand their color palettes. The historical world was a lot more colorful than what Hollywood portrays, take a look at Landsknecht uniforms if you want an idea of the range of color available to the elite, but even peasants could access an array of color from plants. For instance: iconic Scottish tartans were made with threads dyed with the pigment extracted from the local area’s lichens, mosses, and plants, tying clan identity to the land. There are literally thousands of traditional tartan designs. Variations in shades or drastic changes to color could be achieved with additions of acids or bases, combined with the use of different mordants (dye fixatives) and even further variations can be made; from a few plants a large palette could be assembled. This is chemistry! This is experimentation!

The world of natural pigments is vast and is the foundation of a marriage between art and science that is astounding to explore. Historical paintings are carefully managed science experiments, preventing or encouraging these reactive pigments reacting to one another, layering and placing brushstrokes so certain colors don’t touch, creating new colors on a palette through the addition of an acid, base, or reactive mineral, mixing a reactive pigment with another to surprising results. Suddenly I am in awe of the breadth of the natural knowledge of our predecessors that we stand on the shoulders of every time we pick up a 96 pack of Crayola crayons.

So I got to thinking, what are natural pigments found in Massachusetts? And there are many: Pokeberry, blueberry, oak galls, walnut, ferns, lichens, dandelions, and many others lead to a rainbow of locally sourced color when harvested and prepared correctly. An easy pigment to extract? Acorn brown. It’s as easy as making a kettle of tea and creates a rich, hearty, autumnal brown drawing ink. I had to try my hand at it. Armed with a plastic shopping bag full of foraged acorns I took over my mother’s kitchen while she was away in New Hampshire (don’t tell her) and boiled up a batch of Acorn Ink. Three hours of boiling them in a bath of water and tablespoon of vinegar later I now have a mason jar of ink to paint with and I can’t stop thinking about harvesting pigments in the spring.

Written by Julia Ledo, WLT TerraCorps Service Member

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