One of tne of the most important things designers work with is color. Every element they draw, type, or generate with a computer, gets a color. It is impossible to create anything visual without making color decisions. And to make things harder, estimates of the total number of discernable colors range from one hundred thousand to ten million. Add issues of human perception and color vision deficiency, and you could get a headache doing anything with colors, let alone building a color scale for data.
Luckily, you have some great tools at your disposal to help with color decisions. These tools incorporate different approaches, so each one is good at slightly different things. There are two main classes of tools for dealing with color. The first class is intended to help with design decisions, and the second class covers data driven color scales.