Long before there were six-digit hexadecimal codes for color (red #FF0000 or green #000800), there were paint-by-number craft activities. And there is synaesthesia (syn -joined, aesthesia -sense), a neurological condition in which two or more senses are connected. For example music might be "seen" in colours and patterns, or taste may have shapes, or letters and numbers have textures.
Miroslav Holub (1923-98), Czech poet and research scientist (and one of my favorite poets) establishes number-color pairings in the following poem:
Brief Reflection on Colors
Blue is certainly number four or even
the vowel o, including birds and smoke
of native Ithaka.
White is number one then, same as the vowel i,
as long as it's out in the cold and not aligned.
Then it also means the future of flowers,
the past of books; blindness of the earth,
opaque till now. Silence.
Black can be the number of nine as long as it's not in the
of very refined numbers, even numbers fade
if they're sophisticated; you too may be black
sometimes, blackness can also occur in
skull-like cliffs and caves; yes and in the order
and anger of matter.
Red on the other hand is three, and as five
it's lighter, more brown. The letter a is red
like the open mouth of a small animal. Also,
battle is red and Faust's pen and love
in summer. And the fanfare of hope.
Therefore, we have an equation in four colors.
4 = 1 x 9 - 5, likewise olive groves by the sea
during the equinox and the period between
two wars, which happens once a year at most.
No wonder the authorities don't love poetry and
linger in the shadows where nobody can see
how worried they are about the strict order of
This translation of "Brief Reflection on Colors" is found in Sagital Section, Field Translations Series 3 (Oberlin College Press, 1980); the translation is by Stuart Friebert and Dana Hábová. Additional postings (in 2010) featuring work by Miroslav Holub include: March 30, April 28, August 19, and December 9.