100x or "resolution" doesn't convey it correctly in my opinion. It makes you think they can distinguish more shades of the colors we all know. As if it was a quantitative difference. But the difference is qualitative, they see colors we don't see. We are color blind to them.

It's not, because higher resolution in the existing channels is completely different than additional channels.

You can't replicate RGB with just R an B, even if you crank up the resolution.

So… 128x?

I don't know where they get the bit count from, it seems to be based upon an understanding of the cone's operation that I've never seen justified in any of these articles.

Assuming that the cones of different frequency range have approximately the same degree of sensitivity, I'd be thinking that the number is about n^(4/3) where n is the number of colours perceivable by trichromats.

But even if that's true - which I doubt - the additional colours are in unlikely to have a useful distribution, and will be centered around the frequency response curve of the fourth cone (I believe it's generally in the yellow spectrum; somewhere between red and green).

If you wanted to measure it in a principled way you could count how many colours they could distinguish. https://en.wikipedia.org/wiki/MacAdam_ellipse

7bits would be 128 times.

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