Russian author Vladimir Nabokov was known to associate colors with letters and numbers, a phenomena known as synesthesia. In his autobiography Speak, Memory Nabokov goes into detail about this and describes his associations with each letter of the English alphabet. This site is meant to depict a visual approximation of Nabokov’s synesthesia.
weathered wood / polished ebony
(hard) vulcanized rubber / (soft) rich rubbery (brown)
drab shoelace (brown)
paler than soft g brown
fold of pink flannel
ivory-backed hand mirror
"browner than k" (blue)
a sooty rag being ripped
azure and mother-of-pearl
brassy with an olive sheen
dull green, combined somehow with violet
The word for rainbow, a primary, but decidedly muddy, rainbow, is in my private language the hardly pronounceable: kzspygv.