[nine_k]

What we call "magenta" is the sensation of both red and blue color-sensitive cells in the eye being excited at the same time. There's no single wavelength that produces this effect (unlike e.g. yellow). The closes you can get is violet, which looks faint to the eye.

A rainbow gives you both red and blue; mute everything else, and you'll get magenta. That's what magenta pigments do when illuminated by white light (which is a rainbow scrambled).

[dnnddidiej]

It never clicked before that yellow and magenta are snowflakes to each other in this regard. I thought they were equals, but magenta is more majestic!

[dyauspitr]

Saying a wavelength doesn’t do it doesn’t make any sense. If you can perceive it visually, a wavelength is doing it.

[nine_k]

Two wavelengths do it; one does not suffice. It's like a perfect fifth can not one note.

[dyauspitr]

The interference is a wavelength too. Maybe not pure but it is one. Afaik they cannot be interpreted as two separate wavelengths and then “brain combined” when the aperture (the retina) is so small.

[dnnddidiej]

I haven't heard of a wavelength of 2 frequencies merged. It is like saying what is the wavelength if you tune to 2 radio stations with 2 radios (assume silent transmition for simplicity). There are 2 wavelengths.

[thaumasiotes]

> I haven't heard of a wavelength of 2 frequencies merged. It is like saying what is the wavelength if you tune to 2 radio stations with 2 radios

No, any wave has a wavelength. You can add sin(3x) to sin(2x) and the resulting wave is a perfect fifth. Its wavelength is determined by its components; since sin(2x) has a wavelength of π and sin(3x) has one of 2π/3, the combined wave will have one of 2π.

The difference is that sin(2x) and sin(3x) are both sine waves, while their sum is not. There is no such thing as a pure tone of two merged frequencies, but there are many possible waves at any given frequency that aren't pure tones.

[dnnddidiej]

Thanks, interesting!