[subb]

You did send a specific wavelength to your retina, but that wasn't violet. Because violet is a construct by your brain.

Color is not a property of wavelength. There's nothing special about photons wiggling in the 380 to 750nm range.

In general it's not necessary to be this pendatic, but given the topic here, I think it's important to realize this. It takes a while because we are so good at projecting our internal experience outward.

Remember the blue / black dress?

[eviks]

> did send a specific wavelength to your retina, but that wasn't violet.

It was, by definition

> Color is not a property of wavelength.

Sure, it's a label

> There's nothing special about photons wiggling in the 380 to 750nm range.

There is - they activate different receptors your brain relies on, hence leading to a distinct (from other wavelengths) sensation

[subb]

The waves aren't inherently special, your retina is.

What if we were sensitive to the 200 to 500nm range? What would be blue, violet and red then?

Our eyes and brain are the one constructing what we perceive as color. It doesn't exists outside of us.

Here's good article on the subject: https://anthonywaichulis.com/regarding-perception-photograph...

[Smithalicious]

>What if we were sensitive to the 200 to 500nm range?

https://www.youtube.com/watch?v=A-RfHC91Ewc

[tianqi]

In my personal conception, violet is the kind of colour at the lower edge of the rainbow, which is a single wavelength. And purple is what the brain constructs. However, of course, the names of the colours are themselves vague.

[subb]

Maybe that's a language issue, because purple and violet are color names around here.

And as such, they are both a construct of the brain, as any other colors, like... white.

What we label as "violet wavelength" is only a narrow projection of our experience outward. Case in point, we don't have such colorful (eh) names for other EM wavelength.

I say narrow because you could take this pure laser and change th surrounding and you will inevitably perceive it differently, even though the power and wavelength are the same.

[bdelmas]

Hmm if you talk to a colorist violet and purple are 2 different colors one more on the red and the other more on the blue. That’s still the construct of 2 wavelength colors. So a made up color of our brain that doesn’t exist.

[dleary]

"Violet" is a spectral color, which means that it is a color formed by a single wavelength of light. And it is a member of the rainbow (the spectrum).

"Purple" is a mixture of red and blue.

[carlosjobim]

Violet is a real wavelength, below blue on the spectrum. Where it becomes invisible to the human eye, it starts getting called ultraviolet.

Magenta and purples are constructs by the brain, as you mention.

[subb]

No, they are all constructed, including blue.

If I shine some wavelength to your eyeball and you say "it looks blue", but then I change the surrounding and now it looks white, I don't think you would conclude that the original wavelength is blue.

We have a many examples like this, which prescribe that vision is not at all an accurate wavelength measurement device.