I presume everybody else sees the same strips that I see. If we were not colour blind, a rainbow would simply be a continuous blend of colours from one end of the spectrum to the other.

It would be interesting to ask a person with tetrachromat vision to depict a rainbow by drawing outlines of the stripes that they observe.

I see the ones that I was told to see: ROYGBIV — seven.

Trichromat vision includes 3 cones which, if they were digital (on/off), could code for 8 colours (2 to the power of 3 — where on/off has two states and there are 3 distinct cones). So it is perhaps no coincidence (really?) that culturally, we speak of 7 colours in a rainbow (how many do various cutures distinguish, I wonder).

I presume that we speak of only 7 rather than eight because the 3 cones are not perfectly distinct — they overlap — and so we observe fewer than 8 distinct colours

Using the same thinking, it seems that tetrachromats should observe no more than 16 stripes(2 to the power of 4) in a rainbow.

Amd now that I’ve taken the anomoloscope I am reflecting on the results (I only matched one), and I realize that the principle that underpins this test might also be used to argue in support the hypothesis that a tetrachromat would ineed see more than 7 (but fewer than 16) stripes in a rainbow.

But I’ve never heard anybody (first hand or second hand) describe a rainbow with more than 7 stripes. It seems that if such people exist they must be quite rare.

I have a colorblind son and I was wondering if I could have tetrachromacy. After all sorts of tests I found out he’s got protanopia. I guess I don’t have an extra cone at all. Well I should have know by now that I don’t have super color vision, only normal color vision. :) Oh well.