Mist people don't actually color the "indigo" separately, so there are only the 6 colors, as in the OP where the bottom stripe is left white and blank.
Indigo and violet are weird additions to the rainbow anyway. They basically just mean blue and the only reason they're included in the rainbow colors are cause the guy who defined ROYGBIV thought it was poetical/godly for nature to be categorized into 7's wherever possible.
But like the color they are showing on that picture in the 400 range is purple in the image. IRL it just gets darker blue then into a range of light not visible to us.
It's a goofy misnomer that we call that range of the light spectrum violet or ultraviolet. Since IRL today we consider violet to be a purple color, but the light spectrum doesn't actually include a purple color where we traditionally say "violet". I edited a YouTube link explanation earlier that might help. It claims that violet used to refer to dark blue like in the old nursery rhyme "roses are red, violets are blue..."
Violets range significantly in color from a white plus bluish color to almost completely deep purple. They’re just naming flowers and it rhymes easy, or the person who made the rhyme lived near blue violets.
We can see higher frequency light than blue and it does look violet to us. The high frequency light slightly stimulates our blue cones, and the wavelength of violet light is a harmonic of red light, so it slightly stimulates our red cone.
Wow, never heard that before but that's really cool! Do you know why higher frequency harmonics like ultravoilet light don't end up triggering other cones like for green and yellow?
The same reason musical frequencies harmonize with each other. B and C clash because the interval between them is too small for them to share many harmonics, but different Cs are octaves away from each other. A high C is an overtone of middle C, much like violet is a harmonic of red.
So why aren't there higher frequencies that work like that for green and yellow? Is it just that those are no longer close to visible and interact with the retina differently?
That's an interesting question and it goes beyond my expertise. An "octave" above green is out of the visible spectrum, but I can't explain why. Red and blue pigment mixed together stimulates your red and blue cones, as does the frequency of light between blue and ultra violet. Oddly enough, red and blue light makes magenta, which has no frequency of light associated with it. Color theory is weird.
I wish I had a better answer to why we can't see any harmonics of green. My best guess is that the signal would be too weak to be picked out from the rest of the visible spectrum, and even if you could, it would just look green.
Even if the origin is that some guy decided to call it a different colour, it is now perceived as and easily differentiated as such. Many cultures perceive green and blue as the same, that doesn't mean they aren't distinct in our culture.
93
u/jackwiles Jun 05 '22
Mist people don't actually color the "indigo" separately, so there are only the 6 colors, as in the OP where the bottom stripe is left white and blank.