You can do that with white light, but not in the rainbow, because the wavelengths are spatially already separated. So you would also have to combine them again.

that is a nice video. and it has 50000 times more views than mine :)

I agree

that is a very good point! YouTube does not let you change videos, but I will keep this in mind for the next one.

No it does not. The rainbow has all wavelength within the visible spectrum. But not all colors. And yes, color is based on perception.

No. It has to do with spectral color hues and non-spectral color hues. Actually there is a lot of confusing information out there.

… also there are different choices for the scaling of the hue axis, so the percentage can change. This is also noted in the vid.

Exactly! And that is what I say in the video. Just that I tried to find a simple title.

Only a Sith deals in absolutes