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Purple Isn’t Real

So we all know the color purple has always been associated with royalty because the dye used to make it was extremely limited because you could only get it from the Phoenician city of Tyre where a tiny snail lived. Dye makers had to “crack open the snail’s shell, extract a purple-producing mucus and expose it to sunlight for a precise amount of time,” and it took 250K snails to make an ounce of dye. But did we know purple isn’t like all the other colors?

Most of you here probably know that our perception of color comes down to physics. Light is a type of radiation that our eyes can perceive, and it spans a certain range of the electromagnetic spectrum. Individual colors are like building blocks in white light: they are subdivisions of the visible spectrum. For us to perceive an object as being of a certain color, it needs to absorb some of the subdivisions in the light that falls on it (or all of them, for black). The parts it reflects (doesn’t absorb) are what gives it its color. But not so for purple, because it is a non-spectral color.

Hahahah. Yessssss. Pound sand, Harold!

Discussion  3 comments

Jesse R.

Our brains don't know the difference between spectral and non-spectral colors - whatever tickles the right combination of cones will make us perceive (more or less - ignoring other perceptual factors) a color. When we're looking at a computer screen any color other than pure (in the native color space of the display) red, green or blue is actually a non-spectral color. We can see this with a spectrometer, but using just the meat in our heads there's no way to distinguish spectral from non-spectral colors. Just one way in which our perceptions are a step or two removed from reality!

Joseph

Perhaps I overlooked the link to the source of the quote in the post; in any case, this seems to be it: https://www.zmescience.com/feature-post/natural-sciences/physics-articles/matter-and-energy/color-purple-non-spectral-feature/

Aaron CohenMOD

Dang it, thanks. That was an oversight on my part. Putting it back in now.

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