John Keats is well known for saying that beauty is truth and truth beauty, but he also had some interesting ideas of color, according to this letter to his fiancée, Fanny Brawne:
I have been writing with a vile old pen the whole week, which is excessively ungallant. The fault is in the Quill: I have mended it and still it is very much inclin'd to make blind es. However these last lines are in a much better style of penmanship thof [for though] a little disfigured by the smear of black currant jelly; which has made a little mark on one of the Pages of Brown's Ben Jonson, the very best book he has. I have lick'd it but it remains very purplue [for purple]. I did not know whether to say purple or blue, so in the mixture of the thought wrote purplue which may be an excellent name for a colourmade up of those two, and would suit well to start next spring.