In Robert Simmon's Subtleties of Color, Simmon writes about effective use of color and how it can be used to optimize data visualization in a world where computer colors are linear and symmetrical, whereas human color perception is non-linear and uneven. He outlines the principles behind the “perfect” color palette, describes different types of data that require unique types of palettes, gives some suggestions for mitigating color blindness, and illustrates some tricks enabled by careful use of colors.
Simmon states that of the three components of color (hue, saturation, and lightness) that lightness is the strongest, and as a result, clear, one-way changes in lightness are more important than those in hue or saturation. He moves on to state that different palettes are suited to specific types of data. For example, sequential data (data that varies continuously from a high to low value; such as temperature, elevation, or income) is most optimized by a color palette that shifts linearly from light to dark. Divergent data (data that varies from a central value/breakpoint) it is more important to differentiate data on either side of the breakpoint- merging two sequential palettes with equal variation in lightness and saturation is most optimal for expressing this type of data. For qualitative data (categorical/ thematic data) it is important to use colors that are distinctive from each other. The reading then elaborates on how colors can be connected to meaning.
I thought the reading was interesting because it was an attempt to define optimal color usage on distinct rules and principles, which to my mind, is something that is more intuitive than learned. Whenever I use color, whether it is for illustration or data visualization, I never really distinctly think about why I'm using the color I'm using outside of "well, it just makes sense in this context/ I feel like it describes the feeling I'm going for." It's interesting to read about a process that I think of as being very subconscious being defined and organized in a way that can be learned/ read.