There is the cube-helix approach, but I suspect you're thinking about something else. The linked talk about the creation of the viridis colour map[0] actually

There is the cube-helix approach, but I suspect you're thinking about something else. The linked talk about the creation of the viridis colour map[0] actually spends a good ten minutes on explaining colour theory, and makes it look very simple in the process. About ten minutes in it shows the "perceptual colour space" of a typical non-colourblind person. A few minutes later it shows the color spaces for people with various types of colourblindness. Perhaps one could project one perceptual space into the other in a way that more-or-less preserves the original information, but essentially with more banding? [0] https://www.youtube.com/watch?v=xAoljeRJ3lU https://www.youtube.com/watch?v=xAoljeRJ3lU