Why do colors process in terms of red, green, and blue and not the primary colors of red, blue, and yellow?
Can layering color palettes on top of each other, as is the case with many maps (an "earth tone" color palette for topographical formations, a black one for artificial structures) clutter up the image and make it harder to interpret? Is it better to use a different retinal variable across different dimensions of the same data or can you use color across several different variables in your data?
"Follow good design practice as well as good visualization practice when developing imagery. In addition to color, consider the other aspects of design: typography, line, shape, alignment, etc. Be aware of the media you’re designing for. It may be trite, but a good visualization is better than the sum of its parts. Be aware of how the various elements of your design fit together. How do the colors used for the data interact with labels?"
Is color best used for continuous data variables (for instance, mapping to a gradient of hues to represent something with a large number of degrees between them) or for discrete data categories? (for instance, men vs. women, children vs. adults, or decades of the twentieth century?)