In TV, the 3 primary colors are Red, Green, Blue. Magenta is a secondary color made from combining Red and Blue. That's what makes it easy. Just turn on 2 of the 3 colors you have to make it. It's not a fraction of them, it's just full on of 2 out of 3.
Fun fact: there is no such thing as magenta as a frequency of light, it is a fun trick your mind does to explain both the low energy and high energy receptors activating without the middle energy receptors also activating. In terms of pigment, magenta is one of the primary colors.
Yes, was going to say this. Magenta isn't on a rainbow and isn't really a normal color in that sense. By the weirdness of how our eyes detect colors amd how our brain processes them, magenta is something like an error response catch-all for colors outside our eye's capabilities and from that standpoint it is quite interesting.
Our heads are good at mixing colors, and we register those as colors too. Brown isn't on the rainbow either.
The most interesting color on the rainbow is violet. It registers in our heads as a kind of purple when objectively it's super blue. But the cones that register red in our eyes are also slightly activated with this super blue light, which makes it register as purple in our brain.
I'd love to see an experiment where people are shown both true violet and purple mixed from red and blue in proportions that make it register as the exact same purple as violet does. And then check how many people see a difference between the two colors. That might finally answer the question of whether red in your head looks the same as in my head.
I've always wondered by violet looks purple. Thanks for that.
So, to be clear, it's just a hardware detail with our red cones? They fire in the presence of photons in the red band, but also happen to fire in the super-blue band? It's just an artifact of how they're constructed, either by chance or evolution?
> I'd love to see an experiment where people are shown both true violet and purple mixed from red and blue in proportions that make it register as the exact same purple as violet does.
Isn't this basically exactly what the computer color violet does? E.g. there are photographs of violet at https://en.wikipedia.org/wiki/Violet_(color), which presumably look close to reality, but the hex color is #7F00FF, which has a lot of red in it.
Is that red not there to simulate our perception of violet, if I've understood you right?
Yeah, the computer merely simulates violet by mixing a kind of purple that looks just like violet.
As far as I understand (I'm no expert, I just read this somewhere), red cones also fire for extremely blue (violet) photons. No idea why. Maybe it's blue light of exactly double the frequency of red light?
My guess would be it's accidental, but I truly don't know. It might be interesting to test if animals with different kinds of cones (like butterflies) also have a similar effect for some of their cones. Though of course we'll never be able to imagine the colors they see. We're colorblind compared to them.
It's fortunate that we mostly have 3 categories of cones and also 3 spatial dimensions. Notice that magenta is a vertex (of 8 vertices) in the cube, along with Yellow and Cyan too.
How the particular space (of activation to the 3 categories of cones) is carved out by that cube is something we engineered, and in fact is different across different printing and display technologies.
Interested in what field you get the term ‘rgb float’? Not a term I’ve heard before (and not an accurate one) so I’d be interested if it’s a term of art in some industry...
Computer graphics use floats for color values very often. It was indeed misleading of me to mention floats and then use a hex value to explain it, though. Just a brain fart from seeing it earlier in the thread. With floats it would simply be (1,0,1).
