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    Less Likely To Be Suitable: Crustaceans

    I feel personally attacked.

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      Edward Tufte’s “Visual Display Of Quantitative Information” does a good job of distilling some of these points into more general strategies. For me one of the more illuminating is on the data-ink total-ink ratio. Data ink is the pigmented parts of the chart that provide information, and total ink is all the areas of the chart that have pigmentation. I would caution the reader from taking these guidelines religiously, however if you are faced with a chart that you can’t tame, I think these rules can be helpful.

      Data Ink Ratio = Data Ink / Total Ink
      • erase non-data ink
      • erase redundant data ink
        • avoid patterns that don’t differentiate
      • remove non-data color
      • remove redundant color
        • small spots of saturated color are more effective at carrying information
        • one single color may be enough; no colors may be enough
        • light grey is preferred for backgrounds should you need one
        • fewer colors (Red, Yellow, Blue, Black) provide better differentiation
        • in color maps use a single hue and not the entire color spectrum and not all the hue’s levels
      My personal observations
      • your colors should contrast in value
        • apply a gray-scale filter to your chart to check
        • this helps people with color blindness
        • it also helps everyone else

      The goal in the Data Ink Ratio is to eliminate noise in communication, and express what is important through visuals to your audience. I like to consider how much visual flair my chart needs, and if that visual flair serves the transmission of information. Additionally, it’s absolutely okay to have charts that are purely gray-scale, in fact I personally recommend trying a few when brainstorming. They will by definition be accessible to the colorblind.

      While you might decide not to remove most non-data ink, I hope you will consider it as a possible approach when designing charts. You can always make charts the way you normally do, create a copy, and reduce. Then see if there is anything you want to bring back to your original design.

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        Regarding your last bullet point, I almost always start out with viridis. It is both suitable for conversion into grayscale (e.g., when printing), and (it seems) for three kinds of color blindness.

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          You likely can also hue shift this all you want without issue.