Simultaneous contrast

How it was pinned down

Michel Eugène Chevreul, a chemist, became director of dyeing at the Gobelins tapestry works in Paris in 1824. Customers complained that some colours, the blacks in particular, looked weak. He tested the dyes and found nothing wrong with them. The problem was the colours woven alongside. A black next to a deep blue or violet looked faded and brownish. His book on the subject, published in 1839, set out the rule: two colours side by side each look as unlike the other as possible, in lightness and in hue.

Why the eye does it

The cells that carry signals from the eye do not report raw amounts of light. Many of them compare a small central spot with the area around it, and respond to the difference. This sharpens edges and helps a person recognise surfaces under changing light, which matters far more in daily life than measuring exact colour. The cost is that no colour is ever seen in isolation. The German-born artist Josef Albers built a whole course on this at Yale, and his 1963 book Interaction of Color is still used to teach it.

Why it matters in practice

A paint chip chosen against a white card will look different on a wall beside a wooden floor. A brand colour will shift between a white page and a dark one. A weaver in Varanasi or Oaxaca who changes the colour of the cross threads changes how every other thread reads. The practical lesson is to judge a colour only in the company it will keep. Paint a test patch on the actual wall. Check a logo on every background it will sit on. Expect small areas to be affected more than large ones.

Sources and further reading

• Contrast effect on Wikipedia
• Webexhibits, Color Vision and Art: Simultaneous contrast
• The Josef and Anni Albers Foundation
• Smithsonian Libraries: Color in a New Light