The elections are over and the visualizations of the vote have come out. The red/blue maps, the warpy cartogram maps, the pointillist map, and the eye searing purple map. All well intentioned, many with awful colors.
Above are eight options for red / blue color scales. The top 4 interpolate between the sedate party logo colors (from NYTimes), the bottom are fully saturated red to blue. Each set of 4 bars represents four different interpolation functions: the simplistic RGB and HSV scales and the perceptual LAB and HCL scales.
Which is best? It depends on your goal. But RGB and HSL interpolation are almost always wrong, they’re very misleading. And for everyone’s eyeball safety, please don’t use fully saturated colors.