Robert Kosara has a great writeup on the problems of the Rainbow Colormap, something that’s been a hotly debated topic at the last few VisWeeks and a long-running complaint of many in the scivis field. Perhaps my favorite part is his simple synopsis of why the known-bad colormap still persists:
Given the issues, why are the rainbow colormap and its variants so popular? I think the answer is quite simple: it’s attractive. Using a single hue to show the data would be reasonably effective, but much less interesting to look at. What is more, if you’re looking to read off the individual values, the smooth ramp is actually worse because you can’t look for a particular hue anymore. The cost is that you create lots of artifacts in the map, though.
