With all the monochromatic tweet pics it triggered me to look up color-blindness.
Very interesting dig.
Egyptians were the first to see blue (they were the first to create a blue dye. Later recreated by the Romans).there are articles out now that suggest early ancestors could not see blue until the Egyptians. If you look at the old artworks they landscapes have a vanilla sky. No blue.
Ancient Greeks could distinguish light from dark, red from yellow. They thought honey was green.
Color blindness is mostly on the X chromosome. Females can have it or be carriers if they carry the gene. Men always have it if they got the X gene carrying it from mother.
8% males are colorblind. .4% females.
They mostly cannot see orange (oh the irony of that).
The most common form Protanopia have difficulty distinguishing blue from green and red from green.
Pure red cannot be seen. It appears black.
Purple cannot be distinguished from blue (don't see many purple or orange flags for countries)
All orange, yellow and green shades appear as a dim yellow.
https://en.wikipedia.org/wiki/Color_blindness
Why did Hillary wear a bright purple? Because it looked Blue?