Colour-blindness was discovered by John Dalton (1766-1844) when he scandalised his family by inadvertently buying his mother a set of racy underwear as a birthday present.
John Dalton was so precocious that he was put in charge of the local Quaker school at the age of 12. It was this religious upbringing that helped him to discover his own colour-blindness: the red-green kind, now known as Daltonism. At the age of 26 he bought his elderly mother a pair of stockings for her birthday, which he didn't realise were scarlet. As a devout Quaker she was expected to dress soberly so this caused a miniature scandal in the family - which Dalton was initially at a loss to understand, as he thought they were blue. His brother couldn’t see what the problem was, either – Dalton’s first clue to the genetic nature of colour-blindness. He had a similar problem later in life, when he scandalised fellow Quakers by wearing a scarlet academic gown at an audience with the King; he thought it was grey.
Dalton's theory of colour-blindness was that the aqueous in his own eye was discoloured with a blue tint: he died on 27 July 1844 and, as per his orders, his eyes were removed. Back in the laboratory his strong-stomached assistant Joseph Ransome cut a hole in one eyeball and squeezed out the liquid, proving instantly that the theory was wrong. Daltonism is actually caused by the eye's light-sensitive cells, known as cones, being faulty or missing.
One in 20 men and one in 200 women have some form of colour-blindness. Bizarrely there are four colour-blind snooker players in the world's top 20 (snooker was actually deliberately chosen to be televised to stimulate the sale of colour TVs.)
Contrary to popular belief colour-blind people can become pilots, so long as they don't suffer from the most severe version of the disorder.
Around 1 in 10 Pingelap islanders is colour-blind.
Mere colour, unspoiled by meaning, and unallied with definite form, can speak to the soul in a thousand different ways.
The spotty number cards that are used to diagnose colour-blindness (Ishihara Tests) were designed by Japanese ophthalmologist Shinobu Ishihara (1879-1963) who, while working at the Military Medical School, was asked to screen military recruits for abnormalities of colour vision. The first plate, which is an orange number 12 on a grey background, can be seen by even the most severe Daltonism sufferers.
It is said that this was used by the Army during the Second World War to weed out draft-dodgers – who would pretend they couldn’t see it.
Colour-blind tamarin monkeys are better at catching camouflaged insects than those with normal vision.
Music gives colour to the air of the moment.
Female squirrel monkeys can see in color, but male squirrel monkeys are usually red-green colour-blind.
Bulls are colour-blind. It is the movements of the bullfighter's cape that cause the bull to charge.