We are creating an experience of synaesthesia in our project. So, accuracy is very important to us. However, there are many theories about the relationship and translation from color to sound. The most widely accepted theory seems to be from Newton’s Color Circle from his book from Opticks of 1704, showing the colors correlated with musical notes.
Newton’s Color Circle
Here are a few more examples based on his ratio:
Other explorations of this relationship can be found here: http://www.musicandcolour.net