The Lascaux cave painters made their paints from materials close at hand. Black came from the charcoal of campfires. White was from chalk or bone. Yellow and red were made from dirt containing iron, and brown was made from dirt with manganese. The Lascaux painters created interesting art using only a few colors. But obviously, they saw many other colors in the world around them. What if they wanted to paint the sky or the ocean? Were the painters at Lascaux sad that they didn’t have the blues?

The Lascaux cave painters made their paints from materials close at hand. Black came from the charcoal of campfires. White was from chalk or bone. Yellow and red were made from dirt containing iron, and brown was made from dirt with manganese. The Lascaux painters created interesting art using only a few colors. But obviously, they saw many other colors in the world around them. What if they wanted to paint the sky or the ocean? Were the painters at Lascaux sad that they didn’t have the blues?

Modern painters also can be troubled by this problem, depending upon their medium. Painters’ imaginations are virtually limitless. If a painter wants to paint a never-before-painted color, what does she do? She must find or mix a new paint that expresses that color. New paints require the art of chemistry.

The Chemistry and Physics of Paint

Paint is, after all, a chemical substance. Recipes vary, but generally paint consists of two components. The binder makes up the bulk of most paints. The binder is a liquid “glue” that holds paint together. Binders make paint stick to whatever surface is being painted (a poster board, a canvas, a cave wall, etc.). Suspended in the binder are particles of colored material, called pigment. Some pigments are powdered minerals. Some are extracted from plants. Some are artificially synthesized chemicals. The first human-made pigment was a blue invented by the ancient Egyptians. Egyptian blue was manufactured by baking chalk and sand with malachite (a mineral containing copper). The ancient Egyptians proudly used their synthetic blue to paint the skin tones of Amon, the father of their gods.

Innovative painters don’t always invent new pigments from scratch. Sometimes they create new colors by mixing existing paints. But paint mixing is a tricky proposition. Pigments are colorful because they absorb certain colors of light and reflect others. Blue pigments, for instance, absorb red and yellow light. They look blue because they reflect blue light. A paint that is a mixture of several pigments will absorb many colors of light and reflect only a few. Because of this, mixing paints can result in a muddy brown or a dingy gray, instead of a beautiful new hue.

New Blue Hues

Vibrant new colors often depend on the discovery of new pigments. During the European Renaissance (1400–1600), painters celebrated the arrival of a luxurious new blue called ultramarine. Ultramarine was made from the gemstone lapis lazuli. The pigment’s name meant “overseas” in Italian. It referred to the fact that lapis lazuli was imported from mines in far away Afghanistan. European painters craved the gorgeous blue of ultramarine. The Venetian painter Titian used a particularly pure ultramarine to paint the luscious sky of his Bacchus and Ariadne.

Unfortunately, ultramarine was ridiculously expensive. The pigment cost more than its equal weight in gold. Painters asked for extra money from their employers to purchase the precious blue. If extra funds weren’t available, painters sadly stretched their ultramarine oils by mixing in cheaper white paints. The white paints dulled the intensity of ultramarine’s blue. So did the linseed oil that Renaissance painters used as a binder. Worst of all, the expensive pigment was prone to a mysterious deterioration called “ultramarine sickness.” For unknown reasons, the dazzling blue sometimes faded to a patchy, splotchy, yellowish-gray.

Relief for the Renaissance painter’s blues came from a lucky mistake. Sometime just after 1700 (history has forgotten the exact date), a German dye maker named Diesbach (history has also forgotten his first name) mixed a batch of red dye using impure ingredients. In so doing, Diesbach accidentally invented a new pigment that came to be called Prussian blue. Prussian blue was the first modern human-made pigment. It did not have the brilliance of ultramarine, but it cost much, much less. Diesbach’s mistake made blue affordable. It also stimulated the search for more ways to make pigments on purpose.

The French National Society for the Encouragement of Industry offered a 6,000-franc prize for the invention of a synthetic ultramarine. Two chemists, Jean-Baptiste Guimet of France and Christian Gmelin of Germany, tied for the prize (though only the Frenchman got the 6,000 francs in 1828). Synthetic ultramarine was cooked up by baking sulfur, soda, charcoal, and sand with minerals containing aluminum and silicon. This procedure was very similar to the long lost process of the ancient Egyptians (so in a sense, synthetic ultramarine was “déjà blue”).

Progress with the painter’s blues continued into the twentieth century. In 1928, the Scottish chemist A.G. Dandridge noticed that the reaction of certain chemicals left behind traces of a blue solid. This led to the discovery of a useful human-made pigment called monastral blue. Monastral blue was chemically very similar to chlorophyll, the green pigment responsible for photosynthesis in plants. Although humans first made monastral blue less than 100 year ago, plants have been making chlorophyll for a couple of billion years.

The French artist Yves Klein created a sensation by inventing a novel blue of his own. Klein combined synthetic ultramarine pigment with a unique binder, an artificial resin called Rodopas M60A. Klein’s resin did not mute the intense color of the pure blue pigment the way traditional linseed oil did. Klein named his electrifying new color International Klein Blue (IKB). He protected his idea with a patent in 1960.

To see Yves Klein’s painting "Blue Monochrome", please click here.

To see Franz Marc’s painting “Large Blue Horses”, please click here.

Mary Beth Cox is a chemist and frequent contributor to ODYSSEY. Not surprisingly, her favorite color is blue.

Indigo is most often put to work as a dye. In dyes, the colored substance is dissolved in a solvent (like water, for instance). Indigo, both natural and synthetic, is important in the textile industry. Its dark blue is the standard hue for denim jeans. Around the world, indigo has colored many other things besides cloth. People of various cultures have used indigo as a hair dye or as ink for tattoos.

Unlike many dyes, indigo can be prepared in a powdered form. Particles of powdered indigo suspended in a binder make blue paint. When the Romans invaded Britain, they nicknamed the opposing Celtic warriors picti (Latin for “painted men”) because of the war paint they wore made from woad. The actor Mel Gibson adopted this ferocious look in the 1995 movie Braveheart.

You can make your own blue paint by doing some kitchen chemistry.

You’ll need:

Medium-sized purple cabbage
water
vinegar
baking soda
powdered milk
small pot
slotted spoon
three small bowls
stove

The juice of a purple cabbage isn’t always purple. The juice will change color depending on its pH. At low pH (as in acids), the cabbage juice is red. At neutral pH (water), the juice is purple. At high pH (as in bases), it is blue. You can take advantage of this chemistry to make red, purple, and blue paints from cabbage juice.

Ask for help if you need it using the stove.

1. With a knife, coarsely chop 4 cups of purple cabbage.*** Coarsely means the cabbage pieces can be an inch or two.

3. On your stove, bring the water to a boil. Gently boil the cabbage in its juice for about 15 minutes.

You should now have three dyes in three bowls: a purple, a red, and a blue. Your juices are dyes because the colorful cabbage pigments are dissolved in water. The colors are very pretty, aren’t they?

Making Your Paint

Add the powdered milk for a binder. (If your powdered milk is lumpy, crush it into a fine powder using the back of a spoon before adding it to the dyes.) How much milk you add is up to you. The more milk you add, the thicker your paints will be.

But notice that as you add the milk binder, you lose some intensity of color. This is the problem that Renaissance painters had when they added linseed oil to their ultramarine pigment. It’s what inspired Yves Klein to invent IKB. Just like a professional artist, you’ve got the painter’s blues!

Juicy Art

Being the pro that you are you’ll no doubt make some lovely artworks using your cabbage juice paints. We’d love to see them. Send your painting to: JUICY ART, ODYSSEY, 30 Grove Street, Suite C, Peterborough, NH 03458. Or email it to odysseymagazine@caruspub.com. We’ll publish some of our favorites in an upcoming issue.