I've been researching the relationship between colour and the musical scale. It's a dubious subjective link really.
It was first discussed by Pythagorus ancient Greek philisophers then again in the 1700s by Castel when the ocular harsichord was built. In the 20th century Scriabin composed music with a 'light score' above the music.

In 1938 Charles Blanc-Gatti made an animated film interpretation of the link between colour and the musical scale called Chromophonie