this post was submitted on 19 Jul 2024
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[–] [email protected] 26 points 4 months ago* (last edited 4 months ago) (3 children)

Specifically, purple is not a wavelength, unlike red(s) at ~700nm and blue(s) at ~400nm.

Purple is what human eyes see when the blue and red cones are both stimulated by their respective colours of light.

[–] [email protected] 11 points 4 months ago (1 children)

I like that some people are so confident in their incorrect understanding of something that they'll downvote the correct answer.

What you said is correct.

[–] [email protected] 5 points 4 months ago

Urgh, I go to sleep, wake up, read soooooo much awful wrongness.

Thanks for the vote of ~~confidence~~ fact.

[–] [email protected] 3 points 4 months ago (3 children)

Nope. Purple is a wavelength that partially triggers both the red and blue cones.

The visual spectrum is continuous, not just three wavelengths corresponding to the three cones.

The blue cones and the red cones are stimulated by purple light. It’s a mix of blue and red signals from the retina, but the light is a single wavelength that is actually purple.

[–] [email protected] 12 points 4 months ago

No, purple is a non spectral colour meaning it is incorrect to call it "a wavelength" but rather you say it is a perception of multiple wavelengths. Not that this is special, pretty much everything you see is a non-spectral colour.

[–] [email protected] 10 points 4 months ago (1 children)
[–] [email protected] 2 points 4 months ago

This is the best in depth scientific explanation here, and deserves more upvotes. Thanks, was a nice read!

[–] Honytawk 4 points 4 months ago (1 children)

Purple is a green wavelength that doesn't trigger the green cones in your eyes.

It is made up by your brain.

[–] [email protected] 2 points 4 months ago
[–] [email protected] 1 points 4 months ago (1 children)

So what would be the color created by a wavelength of 550nm?

[–] [email protected] 3 points 4 months ago (1 children)
[–] [email protected] 1 points 4 months ago (1 children)

Ohhh, I think I get it.

Purple is what you get when you force the visible light spectrum into a wheel, so there'll be something that "connects" blue with red?

If so, is the reason we perceive green as a different color than purple is because we have receptors for that specific wavelength, otherwise both colors would affect our red and blue color receptors similarly?

[–] [email protected] 3 points 4 months ago* (last edited 4 months ago) (1 children)

Essentially, yes. Although violet is a colour, and that does correspond to a wavelength of light. I'm not really sure where violet ends and purple begins.

Looks like this guy has had a crack at explaining the difference, though.

[–] [email protected] 1 points 4 months ago