Kassia St. Clair - The Secret Lives of Color

Color is fundamental to our experience of the world around us. Think of hi-vis jackets, brand logos, and the hair, eyes, and skin of those we love. But how is it, precisely, that we see these things? What we are really seeing when we look at, say, a ripe tomato or green paint, is light being reflected off the surface of that object and into our eyes. The visible hit our eyes and are processed by our brains. So, in a way, the color we perceive an object to be is precisely the color it isnt: that is, the segment of the spectrum that is being reflected away.

When light enters our eyes it passes through the lenses and hits the retinas. These are at the backs of our eyeballs and are stuffed with light-sensitive cells, called rods and cones because of phenomenon is not completely understood, but it is usually genetic and is more prevalent in men: around 1 in 12 men are affected compared to 1 in 200 women. For people with normal color vision, when cone cells are activated by light, they relay the information through the nerve system to the brain, which in turn interprets this as color.

This sounds straightforward, but the interpretation stage is perhaps the most confounding. A metaphysical debate over whether colors really, physically exist or are only internal manifestations has raged since the seventeenth century. The squall of dismay and confusion on social media over the blue and black (or was it white and gold?) dress in 2015 shows how uncomfortable we are with the ambiguity. This particular image made us acutely aware of our brains post-processing: half of us saw one thing, the other half something completely different. This happened because our brains normally collect and apply cues about the ambient lightwhether we are in full daylight or under an LED bulb, for exampleand texture. We use these cues to adjust our perception, like applying a filter over a stage light. The poor quality and lack of visual clues like skin color in the dress image meant that our brains had to guess at the quality of the ambient light. Some intuited that the dress was being washed out by strong light and therefore their minds tuned the colors to darken them; others believed the dress to be in shadow, so their minds adjusted what they were seeing to brighten it and remove the shadowy blue cast. That is how an Internet full of people looking at the same image saw very different things.

Whiteness and all gray Colors between white and black, may be compounded of Colors, and the whiteness of the Suns Light is compounded of all the primary Colors mixd in a due Proportion.

Sir Isaac Newton, 1704