Colour blindness is actually a colour alteration. The idea is that people with colour alteration of green and red actually have a higher vision of colour alterations in blues, yellows. Such people see the attributes of other colours in a more heightened aspect than those certified as being colour natural.
The tendency of people with altered colour aspects is interesting in that their perceptions and attractions are to shy away from blacks and greys and a tendency to accept white.
The colour perspective and the colour refractions of gemstones is really interesting, particularly when a man who is colour altered innocently tries to colour match for a woman’s piece of wardrobe.
All to do with receptions and receptors and the refractive index of stones.