“Impossible” colors

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So I’ve been seeing a lot about these colors that aren’t supposed to exist apparently? Like magenta, stygian blue, etc and I kind of get what’s going on but also kind of don’t? I’ve seen explainations of this on the internet before but never fully understood, so if anyones able to help with that I’d appreciate it. Don’t want a watered down explaination (I like technical stuff), just a more understandable and approachabe one

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7 Answers

Anonymous 0 Comments

The first thing to note is that “real” colors correspond to specific wavelengths of light. Photons at 700 nanometers will strike your retina and activate the receptors that are sensitive to that wavelength, and then your brain says “red!” So red is a “real” color because there are specific wavelengths that are red.

It’s possible to lay out [the entire spectrum of colors that map to specific wavelengths](https://www.thoughtco.com/the-visible-light-spectrum-2699036)–all of these are “real” colors and you’ll recognize the rainbow there (sort of). But you’ll also notice that there are a whole bunch of colors missing. Those are colors that our brain makes up to explain confusing signals, which you’re here calling “impossible colors.”

When light from the same source hits the retina and activates *both* red and blue receptors, your brain needs some way to show you reddish blue. So it invents magenta so you can perceive something.

To make the whole thing even a bit messier, even “real” colors involve some degree of brain legerdemain. You’re probably aware that we have three color receptors in our eyes: red, green, and blue. Whence then orange, yellow, and violet? (Purple, it should be noted, is one of those “impossible” colors although I couldn’t begin to distinguish between it and violet personally.) Turns out your color receptors don’t *just* perceive the colors for which they’re named. They cover a little bit to either side, even overlapping each others’ territory a bit. And, weirdly, Blue kind of “wraps around” and activates the red receptors a little bit. So when violet light–a discrete wavelength–hits the retina it activates the blue receptors and also a little bit of the red receptors, so your brain interprets that as violet.

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