Aiyo, colour blind is your brain can't distinguish the correct
color you saw.
You can call it evolved vision also.
Same for crabs or insects, their colour defination is different
from ours.
Your genes have some changes therefore gives you monochrome
sight.
It might be a confusion of colour also. A picture with too many
colour your brain might not be able to filter and define them,
therefore leaving them as the basic of all colour, black and
white.
I don't know is this called phychology or what, but confirm
something wrong with your eyes, brains for both lar. lol
