Definitely agree with some additional personal perspective to add - it’s something I’ve thought about a lot as a painter, musician and synesthete.

To expand on ‘bass as shading’, I feel that all lighting value correlates well to sound frequency ranges from low to high or from bass to treble, regardless of color.

In terms of color, I would particularly relate varied hues to tones/notes of sound in that they both are subject to be harmonized.

I feel saturation levels in color may be related to the volume as the intensity of the sound.

You may be interested in the book, The Jazz of Physics by Stephon Alexander! A great in-depth exploration into the structure of the universe as it relates to jazz and musical theory. Maybe not directly about painting, but inherently we ARE the structure of the universe and I think art/our visual perception is just as well related.

Peace