Choosing an effective color scheme for data visualization is no easy task. Colors aren't simply used to make a chart look nicer. Besides distinguishing and suggesting associations between sets of data, they also communicate information through aspects such as hue, contrast, saturation, or lightness. They can even influence the mood of the viewer. The choice of colors is never neutral. It may attract or repeal the viewer from relevant information.
Colors that vary in lightness and saturation suggest a sequential relationship (stronger/weaker, hotter/colder). Opposing data can be better represented using divergent color palettes, where extremes are represented by complementary colors. If your data represents different categories, it will be better visualized with a qualitative color scheme. Depending on your audience and the purpose of your...