To expand beyond color, Christopher Healey has an extensive report on perceptions of visualizations and the different elements you can use to identify things [1

To expand beyond color, Christopher Healey has an extensive report on perceptions of visualizations and the different elements you can use to identify things [1]. [1] https://www.csc2.ncsu.edu/faculty/healey/PP/index.html https://www.csc2.ncsu.edu/faculty/healey/PP/index.html