It’s all in the perception, as I said 
That grid-based test of perception does seem to vary between perceivers.
Curiously, I find it most effective in yellow, and totally ineffective in red.
For me, the middle shirt is yellow, but there are grey tshirts with red grids on them:
That is not true in the sense that you seem to mean.
Our eyes receive a spectrum of electromagnetic radiation, but what we perceive is not predictable by physics, and does not bear a direct resemblance to the incoming radiation.
For example, I perceive that the spaces between the yellow grid lines in the picture immediately above are filled with light yellow, wheras close inspection will show they are filled with light grey. If you traced the ray of radiation from the middle of one of those squares to the back of my eye, you would find that “grey” light is arriving there, but I perceive yellow!
And I perceive that the little girl’s face in the movie above it is skin-toned. Wheras richyfortytwo does not - physics of electromagnetic radiation could not predict that.
Interestingly the tennis balls with the dots totally work for me. All the grid stuff works just a little bit for me.
It’s quite an eye-opener to start realising how much stuff our brain totally makes up, totally invents, about what it is that we think that we see.
It’s a deep rabbit hole if you start off down it 
You check out what the video is doing small scale. Then full screen it and look at the yellow dot, and see if your brain lies to you about what is going on…
I find that when I look away from the yellow dot to check the video didn’t actually change, then look back, my brain doesn’t try to lie again, at least for a while…
This one is even more dramatic when it works, because there is no motion involved.
Yep lol your brain is constantly lying to you, often changing reality on a whim to something that is either easier or makes more sense at the time…
I wouldn’t call it a spectrum. The eye has sensors for 3 broad frequency bands, of which at least 2 strongly overlap. You cannot mix wavelength to get an immediate wavelength, but you can mix wavelength to get the same color impression as you would get for a specific wavelength.
It’s funny you say that, because it is certainly true in the way that I meant it:
[…] cells in the retina convert light energy into electrical energy used by the nervous system.
Human eye - Wikipedia
So, my use of the word “perceive” was likely wrong and misleading and I didn’t recognize what you were getting at by saying “color is a perceptual thing”.
You are saying what happens in the brain is most important for the concept of “color” and I’m saying I’m interested in the physics aspect (outside of the human body) too.
In the end I think the both of us aren’t really helping to tackle the question originally raised in this thread.
Edit: I just reread some of your previous posts because of my bold claim (about whether we are helpful to answer the original question) and I found this:
So it seems you did bring up physics earlier, it was just too long ago and not enough for my appetite. 
I think I meant a “range of wavelengths” and I don’t know whether it is correct to call that a spectrum or not, but thanks for bringing up some physics aspects.
Oh, but I already answered that question (in the poll) so this is all just time-filling conversation after that, until the OP illuminates us with his statistics
Spot on - we see what we each mean
I wonder how much interesting stuff there really is outside the body? It’s easy to visualise it as “a bunch of wavelengths going from here to there, nothing much more than that”. Apart from photons vs waves, is there much more going on?
You might have answered that question, but then Atorrante raised the issues with black and white and questioned the choice of possible answers. You tried to help with that at first, but then the discussion moved towards shades and now it is unclear whether the question itself should have been asked differently. Should it be about favorite shades instead?
Isn’t it nice that it is so easy to talk about color when looking at it from a physics viewpoint? And then you can go further and start analyzing colors of stars or atmospheres of distant planets, visualizing infrared radiation observed by the new James Webb Space Telescope. And that’s just from the astronomy part of physics.
One of my favorite puzzles is why the color purple looks like the color violet. I think it’s mostly a problem about the physics of the retina. Another one is how paints and inks mix at the microscopic level and why we use CMYK in printing vs RGB on screens.
Feynman has an interesting two chapters about color and vision:
Maybe we need a new poll 
0 voters
You deserve someone asking “which wavelength is pink?”
Ah discourse didn’t have a fractional vote option, but that would be something like 650 nm with a little bit of everything else
I double checked before posting that comment.
Context is so important.
As a side note, this is one of my most loved apps, I spent hours on it and after solving 1193 schemes I’m still enjoying it.
It shows clearly how much our perception of shades is influenced by the surroundings.
0 voters
I don’t even know what’s the difference between “purple” and “violet”.
In French we have a colour named “violet”, which is most often translated as “purple” in English; and a colour named “pourpre”, which shares its etymology with English “purple” but is actually a shade of red.
Purple is a mix of red light and blue light. Violet is a very deep blue that is so far from our normal cones and on the edge of our vision, that our brains just kind of decide it looks similar to purple for lack of a better option 
Another example of…
