[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.