Color is a great tool for drawing attention to certain data points in a graph, chart, map, or diagram. But, WARNING, color also can confuse the viewer. Adopting a few rules of thumb will turn a rainbow of confusion into an elegant and clear picture:
1) Limit one meaning per color. If you are color coding a map and assigning blue to a certain income range, then do not use blue to mean anything else in that map or adjacent related visuals. Blue always means that specific income range.
2) Limited color palate. Limit your graph, chart, map, or diagram to a few complementary or monochromatic colors. Remember the color wheel? (See image above.) Choose complementary colors that are on opposite sides of the wheel: think orange and blue and yellow and purple. Or choose several tones of one color (a monochromatic color scheme). Looking for an effective ready-made color palate? Check out sites like color-hex.
3) Avoid reds with greens. Seven to ten percent of men are red-green colorblind. They can’t tell the difference between the two. So avoid using them both on a visualization.
4) Dial-up one data point and mute the rest. If you want to draw attention to one point, line, bar, or pie slice, give it a bright color and color the rest a muted shade or gray.
See other data tips in this series for more information on how to effectively visualize and make good use of your organization's data.