Categorical Color Palettes: Distinguish Data Groups Clearly
How to choose categorical color palettes for charts and dashboards. Best practices for distinguishing groups while maintaining accessibility.
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Tags: color, data-visualization, design
Categorical Color Palettes: Distinguish Data Groups Clearly Categorical color encoding is deceptively hard. You need colors that are immediately distinguishable from each other, accessible to color-blind users, perceptually balanced (no color shouts over the others), and still work when printed in grayscale or viewed on a low-quality projector. Most default chart palettes — the blue-orange-green-red-purple rainbow that comes out of Excel, early matplotlib, and most BI tools — fail at least two of those requirements. This guide covers how to evaluate, choose, and build categorical palettes that work. The 12-Color Limit (And What to Do When You Hit It) Human color discrimination in chart contexts typically maxes out at 8–10 distinct categories. Beyond that, readers can't reliably match…
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