Stephen Few关于作图中颜色应用的注意事项的一篇小文档。

Practical Rules for Using Color in Charts
Quick, take a look at this dashboard heatmap done in Excel and tell me if it’s a good or bad use of color:

OK, it’s a pretty nifty excel heatmap, right? Ready for the answer?
According to information visualization and business dashboard expert Stephen Few:

In this example, traffic light colors of green, yellow and red are being used to encode high profits (green), low profits or losses (yellow), and high losses (red) across several product types and states. It is probably true that the values that are of greatest concern to the person viewing them are those in dark red and dark green, but they are the hardest values to read, because there is not enough contrast between black text and dark background colors for the numbers to stand out.

He’s talking about one of his rules about using colors:
If you want objects in a table or graph to be easily seen, use a background color that contrasts sufficiently with the object.
“The above rule cautions us to choose colors carefully, always making sure that they are easy to see and that they effectively serve the purpose for which we are using them. I’ll illustrate this point using a display that is becoming increasingly familiar, but is seldom done well. With Microsoft Excel and several other software products, you can display quantitative data in the form of a heatmap. A heatmap is a visual display that encodes quantitative values as color. We are all familiar with weather maps, which use colors to represent varying amounts of rainfall or degrees of temperature. Heatmaps need not be arranged geographically; they can also be structured as a matrix of cells, such as a tabular arrangement of values in a spreadsheet.”