What kinds of colormaps are best for displaying continuous values in scatter plots (notably due to the background color of the scatter plot)?
So far, I've been using perceptually uniform sequential colormaps for such data. However, if I display this scatter data on a white background, then the lighter end of the colormap is visually underrepresented, as the light-colored data points are much harder to see against the white background than the dark-colored data points (see attached image). This seems to misrepresent the data.
Diverging color maps have a similar issue, with the middle values being over- or under-represented.
Another alternative is a colormap which retains the same brightness, and simply shifts from one color to another. However, people with color-blindness will not be able to view the data.
So I'm now leaning toward using perceptually uniform sequential colormaps where the brightness of the data does not change as much from the one end of the scale to the other. There will still be some brightness change, and so the light-colored data will likely still be underrepresented to some degree, but I hope it will be minimal.
That said, I'm guessing there are people who have spent much more time thinking about this than I have, and I was wondering if anyone has better options, or more detailed thoughts on how to approach this issue.
