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The writing is great, but I keep wondering: Why do so many physicists use Jet or other non-perceptually uniform rainbow-like colourmaps for their graphs? Should

The writing is great, but I keep wondering: Why do so many physicists use Jet or other non-perceptually uniform rainbow-like colourmaps for their graphs? Shouldn't that be part of great science communication, given that about 1 in 12 men have some form of colour blindness? There are so many other visually appealing options [0] that are attractive while still being perceptually uniform. There's even Google's Turbo [1] colourmap for those who refuse to give up rainbow-like colourmaps. [0]: https://matplotlib.org/stable/tutorials/colors/colormaps.html https://matplotlib.org/stable/tutorials/colors/colormaps.htm... [1]: https://ai.googleblog.com/2019/08/turbo-improved-rainbow-colormap-for.html https://ai.googleblog.com/2019/08/turbo-improved-rainbow-col...

petschge 5y ago
Short answer: because none of them is the default in standard plotting tool. There is so many alternative that it is hard to know which replacement you should pick. If you pick the wrong one you are a moron, if you stick with the bad default it's way less noticeable, even if it is a strictly worse choice.
- murphyslab 5y ago
  The default issue is certainly keenly felt. My first scientific publication graphs were done with Jet. But since switching to some of the perceptually uniform ones (most often Viridis), I've never had a complaint. But your point "if you stick with the bad it's way less noticeable" is understandable.
- maxnoe 5y ago
  Matplotlib 2.0 came out in January 2017 and has a perceptually uniform, colorblond friendly colormap as default and three others available. There is no exclude for using Jet today and Journals should reject papers using bad colormaps
ttfkam 5y ago
"...given that about 1 in 12 men have some form of colour blindness?" I guess women are better suited to science work after all. ;)
geokon 5y ago
This feels overengineered... Since it's showing a probability density, wouldn't it make most sense to just use a grayscale in this case? As the probability density approaches zero the visual would disappear as well. This is more intuitive, as the probability is zero off the edge of the graph/page I think you only need this color vomit if you have a change between two states, or you have multiple intermediary states and want some visual "clustering". You can actually see the problem very clearly b/c it ends up having a weird dark-blue to white cut is some of the plots.
- isaacimagine 5y ago
  The advantage of using a rainbow scale as opposed to a gray scale is that a rotation in hue space brings out more 'detail' than a simple black to white gradient.
  - geokon 5y ago
    that's an interesting point I still think it's a bit visually confusing when you're representing the existence or non-existence of something (the planet is in this region, and not anywhere else) You could in theory do both.. rotate in hue and fade to white. If you did it right, when if you printed it out in B&W you'd get the grayscale equivalent :) Maybe it'd look a bit silly
    - hoseja 5y ago
      There are colormaps that are designed to do exactly this, for example the linear maps here: https://colorcet.com/userguide/index.html https://colorcet.com/userguide/index.html
      - geokon 5y ago
        That was a very interesting read. Thank you for sharing. I could really use some of the other color spaces presented too.. in some other situations.. I'll just need to figure out how to plug them into my workflow :) It's strange but the first linear color space (CET-L03 red-yellow-white) seems to go to a lightness of 100. On the far right it looks white as expected. However the other one (CET-L20) looks very nice, but it doesn't seem to reach 100. Even though in the plots and explanation it suggests it does. Strange..

petschge 5y ago

Short answer: because none of them is the default in standard plotting tool. There is so many alternative that it is hard to know which replacement you should pick. If you pick the wrong one you are a moron, if you stick with the bad default it's way less noticeable, even if it is a strictly worse choice.

murphyslab 5y ago
The default issue is certainly keenly felt. My first scientific publication graphs were done with Jet. But since switching to some of the perceptually uniform ones (most often Viridis), I've never had a complaint. But your point "if you stick with the bad it's way less noticeable" is understandable.
maxnoe 5y ago
Matplotlib 2.0 came out in January 2017 and has a perceptually uniform, colorblond friendly colormap as default and three others available. There is no exclude for using Jet today and Journals should reject papers using bad colormaps

ttfkam 5y ago

"...given that about 1 in 12 men have some form of colour blindness?" I guess women are better suited to science work after all. ;)

geokon 5y ago

This feels overengineered... Since it's showing a probability density, wouldn't it make most sense to just use a grayscale in this case? As the probability density approaches zero the visual would disappear as well. This is more intuitive, as the probability is zero off the edge of the graph/page I think you only need this color vomit if you have a change between two states, or you have multiple intermediary states and want some visual "clustering". You can actually see the problem very clearly b/c it ends up having a weird dark-blue to white cut is some of the plots.

isaacimagine 5y ago
The advantage of using a rainbow scale as opposed to a gray scale is that a rotation in hue space brings out more 'detail' than a simple black to white gradient.
- geokon 5y ago
  that's an interesting point I still think it's a bit visually confusing when you're representing the existence or non-existence of something (the planet is in this region, and not anywhere else) You could in theory do both.. rotate in hue and fade to white. If you did it right, when if you printed it out in B&W you'd get the grayscale equivalent :) Maybe it'd look a bit silly
  - hoseja 5y ago
    There are colormaps that are designed to do exactly this, for example the linear maps here: https://colorcet.com/userguide/index.html https://colorcet.com/userguide/index.html
    - geokon 5y ago
      That was a very interesting read. Thank you for sharing. I could really use some of the other color spaces presented too.. in some other situations.. I'll just need to figure out how to plug them into my workflow :) It's strange but the first linear color space (CET-L03 red-yellow-white) seems to go to a lightness of 100. On the far right it looks white as expected. However the other one (CET-L20) looks very nice, but it doesn't seem to reach 100. Even though in the plots and explanation it suggests it does. Strange..