From cave wall to OLED screen: a short history of color

Short answer

Humanity passed through four great breaks in how it made color: first it gathered ready-made colors from earth and charcoal, then it invented a new color in a kiln, in the 19th century it learned to synthesize dye in a laboratory, and finally it took color out of matter and began producing it with light and numbers. Each break did more than widen the palette; it also changed who a color belonged to, what it cost, and what it meant.

The first break: colors gathered from the ground

Humanity's earliest known colors were underfoot. Earth rich in iron oxide — ochre — yields a range of tones from red to yellow; charred wood black, clay, and chalk round out the dark and light tones. Gathering these materials is easy, but turning them into a usable paint takes knowledge: grinding, mixing, binding, and storing.

A cave in South Africa shows how old this knowledge is. At Blombos Cave, archaeologists found a workshop where ochre was ground into a mixture and stored inside two seashells. What the mixture was used for is unknown; both decoration and skin protection are counted among the possibilities.

Cave walls carry the same palette. In a cave on the Indonesian island of Sulawesi, a red-painted scene showing people and wild boars together was determined to be at least 51,200 years old; a hand stencil on nearby Muna island was calculated to be at least 67,800 years old. Both dates rank among the oldest examples of this kind of find. Why the palette was so narrow, and specifically why blue and green never appear, is the question TK-01 asks.

The second break: blue born in a kiln

A durable blue pigment that could easily be gathered in nature was close to nonexistent. In ancient Egypt, this gap was filled by an invention: when sand, lime, a copper-bearing mineral, and a flux were fired together, a bright blue emerged. This material, which we now call Egyptian blue, is considered the first synthetic pigment humans deliberately produced. How it was made, how it spread, and how the recipe was later forgotten is told in TK-02.

The meaning of this break is this: color was no longer only something to be found, but something to be made. But making it was hard and expensive. Purple extracted from sea snails, or blue made from lapis lazuli brought from Afghanistan, remained a status symbol for centuries; these stories are told separately in TK-03 and TK-04.

The third break: dye from the laboratory

In 1856 in London, an eighteen-year-old chemistry student, while trying to produce a malaria drug from coal tar, obtained a brilliant purple dye. William Henry Perkin's discovery launched the age of synthetic dyestuffs. Within a few decades, reds, blues, and greens began to be produced in laboratories, and factories manufactured them by the ton.

The real effect of synthetic dyes showed up in price. Intense colors that once only the wealthy could wear entered ordinary people's closets. The prestige a color carried because it was rare eroded; color stopped being a marker of class and began turning into a personal preference. The details of Perkin's story are covered in TK-08, and the dye industry's effect on the economy in EC-03.

The fourth break: color from light and numbers

In the twentieth century, color was separated from matter for the first time. A television or computer screen works not with paint but with light: tiny subpixels emitting red, green, and blue light glow at different intensities to evoke millions of colors in our eyes. Color itself is now a string of numbers. For these numbers to show the same color on every device, a common language was needed; sRGB, proposed in 1996 and made an international standard in 1999, became the most widespread of these languages.

Today, on the OLED screens in phones, every pixel produces its own light. The foundation of this technology was laid in 1987, when Ching Tang and Steven Van Slyke, working at Eastman Kodak, introduced an organic thin-film diode that emitted green light. How screens produce color is explained in detail in EK-01 and EK-03.

This last break also has a cost: color standards and cameras were, for a long time, calibrated around one particular skin-tone reference. The question of whose skin a technology's default was built around is the subject of FS-09.

Example — touring the four breaks in a museum

A visitor walking through several halls of a large archaeology and art museum can see these four breaks in order. In the first hall, designs made with ochre and charcoal; in the second, small figures painted with Egyptian blue; in the third, the brilliant purple and green dresses of the late 19th century; and at the exit, digital copies of the works on touchscreens. The same blue turns out to have been produced four different ways across the four halls: not from earth, but from a kiln, then from a laboratory, and finally from light.

Common misconception

Summary

1. The first colors were gathered from earth and charcoal; the workshop at Blombos shows this is knowledge at least 100,000 years old.
2. Egyptian blue was the moment color was invented for the first time, while the 1856 purple dye was the moment color became cheap through industry.
3. In the digital age, color turned into light and numbers; that made standards, and who they assumed, matter.

Test yourself

1. (Easy) What is the main compound that gives ochre its color?
2. (Easy) What is the first known synthetic pigment?
3. (Medium) How did synthetic dyes change the social meaning of colors?
4. (Medium) A screen produces color with light, not paint; what does this mean?
5. (Hard) Why is it wrong to explain the absence of blue and green in cave paintings by saying "ancient people couldn't see these colors"?
6. (Hard) How does a hundred-thousand-year-old workshop show that producing color is a matter of knowledge, not just material?

Answers

1. Iron oxide; it gives tones from red to yellow ("The first break").
2. Egyptian blue, that is, calcium copper silicate; its use goes back to the earliest Egyptian dynasties, around 3100 BCE ("The second break").
3. They made cheap the intense colors that carried prestige because they were rare and expensive, and opened them up to everyone; color stopped being a marker of class and began turning into personal preference ("The third break").
4. Subpixels emitting red, green, and blue light glow at different intensities; color is not a material but the numbers that define these ratios ("The fourth break").
5. Vision was the same; what was missing was durable blue and green pigment that could easily be gathered ("Common misconception").
6. The workshop had a toolkit showing steps of grinding, mixing, and storing; finding the material wasn't enough — turning it into paint required knowledge of a process ("The first break").

Sources

• Henshilwood, C. S. et al., "A 100,000-Year-Old Ochre-Processing Workshop at Blombos Cave, South Africa," Science 334, 2011.
• Oktaviana, A. A. et al., "Narrative cave art in Indonesia by 51,200 years ago," Nature 631, 2024.
• "Rock art from at least 67,800 years ago in Sulawesi," Nature, 2026 (team from Griffith University, BRIN, and Southern Cross University).
• ColourLex, "Egyptian blue" entry.
• Siddall, R., "Mineral Pigments in Archaeology: Their Analysis and the Range of Available Materials," Minerals 8(5): 201, 2018.
• Anderson, M., Motta, R., Chandrasekar, S., and Stokes, M., "Proposal for a Standard Default Color Space for the Internet — sRGB," IS&T/SID 4th Color Imaging Conference, 1996.
• Tang, C. W., and Van Slyke, S. A., "Organic electroluminescent diodes," Applied Physics Letters 51(12): 913–915, 1987.

Next step

TK-01 opens up the first break: it examines, one by one, the prehistoric palette made of ochre, clay, charcoal, and bone black, and asks why blue and green are absent from cave paintings. TK-08 returns to the third break: it tells the story of Perkin's 1856 accident, coal tar, and the "mauve mania," showing how synthetic dyes democratized color.