After I graduated from the University of Pennsylvania in 1974 I went into my third floor and spent a lot of time thinking about how I was going to go about making colors do what musical notes do so well.
8" x 6"
Notice how red and green are about the same tone or shade. (These terms apply to the amount of light a color reflects) Yellow has a lot of light and purple keeps its light to itself.
NEWTON'S DIAGRAM OF COLOR SOUND RELATIONSHIP
to be continued....
Please pass along to anyone you think may be interested.