More colors today, partly in honor of the fact that Alan’s color idioms project just crossed the 700 idiom mark. It’s idiotastic! Since it got picked up by a few blogs (like this and this), it’s even surpassed the Elvish page to be the single busiest page on my site.
This particular post, however, isn’t about how we talk about color but rather how we see color. Here is a very basic question: What is color?
You might reasonably expect a solid physics-based answer to this question. But it’s not so simple. To start the discussion, here’s a diagram that used to puzzle me extremely.
It’s our friend the electromagnetic spectrum. It spans an absolutely vast frequency range of the various kinds of wiggling that photons can do. But look at that rainbow band in the middle that defines visible light. It’s a teeny weeny little thing. You’re being bombarded by electromagnetic radiation all the time and from every direction, and all you can make out is this tiny little sliver of it. Why is that? Why can’t you see ultraviolet and infrared? What color are microwaves? Your iPhone is brilliant twinkling flashlight that distant antennas can see. Why can’t you?
It was a long time before I realized that the problem is framed partly by the chemistry of the eye. Your retina is a delicate lawn of special proteins that sense light when they’re jostled by arriving photons. But if you jostle them too little or too much, no light gets sensed. By way of analogy, think about the annoying wind chimes on your neighbor’s porch. If the wind is a soft lazy breeze, no chime. If it’s a hurricane, the whole apparatus blows away. No chime. When infrared comes knocking on the old eye-door, it may warm your retina, but there’s no chime.
In short, color is defined by physiology. Color is the thing that looks like this. The human is in the loop. I can write the most quantitative of equations about the frequency, wavelength and energy of photons, but as soon as I mention color (or sound for that matter) I have to put an unreliable blob of protoplasm in the driver’s seat. And the way humans sense color is very complicated. And that is what leads us to this enjoyable essay by Jason Cohen of the Smart Bear blog: Color Wheels. For even more detail, Jason points us to this monograph by the enigmatic Bruce MacEvoy.