Data visualizations are beautiful, exciting ways to tell stories. But you have to choose carefully in designing a map or chart, and one of the biggest mistakes is misusing rainbow colors.

Rainbow color schemes — also called spectral color schemes — are frequent choices for visualizing data, both because they look bold and exciting and because they’re the default for many visualization software tools. But they usually do more harm than good. Detecting the colors at all is a problem for more readers than you might guess, and the rest of the audience will find it easier to understand the visualization if it’s presented with a different palette.

Rainbow color schemes are “almost always the wrong choice,” Anthony C. Robinson, geography professor at Pennsylvia State University, wrote in an online class on Coursera, which taught students how to use geospatial technologies to map data.

Here are some reasons why rainbow colors are the “wrong choice”:

(story continues)

Check out my article to learn why rainbow colors might kill your data visualizations. Read on to figure out what colors you should use.