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Comment by beardyw | Hacker News Reader

I am not sure white, grey and black are colours at all, since they are just degrees of illumination. To me a colour has distinct series of wavelengths. Maybe I'm wrong.

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The obvious follow-up questions: Is magenta a color, despite requiring two wavelengths? Is brown a color despite being just dark orange? Is metallic gray different from gray (i.e. does light scattering matter)? What about subsurface light scattering, like in skin or translucent plastic?

Color is a bit like our classification of continents: it's useful, but only makes sense if you don't look too hard. And maybe it's fine if webdesign and miniature painting have different opinions on what makes a color a color.

For context, Technology Connections did an entire video on the brown color: https://www.youtube.com/watch?v=wh4aWZRtTwU

All colours (pretty much) are a wide spectrum with varying amounts of every wavelength. Our eyes do a pretty poor job, compared to sound to our ears, of separating out the wavelengths, just boiling them down to a single hue.

The folks examining fine art do a full spectral analysis of paint to verify it's authenticity. Something the human eye can't do.

Yeah, that's another giant can of worms. Light with a wavelength of 600nm is orange, but there is a combination of red and yellow light that is indistinguishable from 600nm light to us. Worse, there is an infinite number of combinations of two or more different wavelengths that look indistinguishable from 600nm light to us. Yet any other species would disagree that they look the same. Or a human with slightly shifted sensitivity spectrums of their rods or cones.

One the one hand it's great because it makes full-color print and screens so easy. On the other hand there is so much information in light that is simplified away by our eyes

What you're referring to is usually called a spectral color. It's the most common form of color, but it's not the entirety of the term. Whites and grays are the achromatic colors.

Metameric colors can have different spectra even when they look identical. You're probably familiar with magenta, a color that has no monochromatic wavelength. More exotic is stygian blue, a color that has no wavelengths at all.

Different people don't perceive the same wavelengths identically either. For example, colorblindness exists and there are genes which slightly shift the opsin sensitivity curves in your eyes.

Color is a very, very deep rabbit hole.

our eyes invent colors that aren’t even there “physically” in tbe true sense of the word. and colours are even cultural, so there is a lot of leeway with what a colour even is. even in genders there are differences in cultural colour perception.

non-spectral colours are very real: greyscale, pink, brown, and purple which are mixes of multiple wavelengths of light

then you have things like:

* green is blue (japan/china)

* homer’s wine dark sea

* colour word development which has some near-universal linguistic phenomenon where the start is light and dark words, then red, and there’s a list on and on.

>homer’s wine dark sea

easily imaginable for the sea at sunset.

It’s also pretty evocative language, which is probably why he’s the guy who wrote it. It’s something you can see in your mind, and when you see it you get a sense of its gravity.

Everything in a paint store is a colour!

This would be an overcomplication in every day vernacular.

What color shirts do you have? Oh we have green, blue, red and none.

How many types of none? Oh we have bright illumination, dark illumination, and 50%.

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