How do you properly select a colormap for a graph? What makes the rainbow color map a wrong choice, and what are the proper alternatives?
Today, I stumbled upon a lengthy post that provides an in-depth review of the theory behind our color perception. The article concentrates on quantitative colormaps but also includes information relevant to selecting proper colors for categories.
https://nightingaledvs.com/color-in-a-perceptual-uniform-way/
If you never learned the theory behind the color and are interested in data visualization, I strongly suggest investing 45-60 minutes of your life in reading this post.