Categorical
Use for unordered groups. Keep the count low, order legend entries by the story, and avoid assigning rank through hue.
Color Scheme Style Guide
Which palettes to use for categories, order, divergence, status, and emphasis.
Color is a reading aid. It should separate meaning, not decorate the page. Pick the scheme by the role color plays in the figure: category, ordered value, difference from a midpoint, semantic status, or single-point emphasis.
Text target
4.5:1
Minimum contrast for normal text and figure notes.
Mark target
3:1
Minimum contrast for meaningful graphical objects.
Default hue count
5
Categorical figures should stay small and directly labeled.
Accent count
1
A single highlight works better than many competing accents.
Default choice: use a neutral page, dark text, one restrained categorical palette, and one warm highlight. Add sequential or diverging scales only when the data is ordered.
Recommended Schemes
Sequential
Use for ordered magnitude, density, rate, or intensity. Light means less, dark means more unless the figure states otherwise.
Diverging
Use when values move away from a meaningful center: target, zero, baseline, forecast, or policy threshold.
Semantic
Use for status, pass/fail, risk, missing data, or system state. Pair the color with text, icon, border, or position.
Highlight
Use mostly neutral marks, then apply one accent to the record, threshold, or segment that carries the conclusion.
Neutral
Use neutrals for page structure, grids, axes, tables, unavailable data, and secondary marks.
Pick The Scheme By Job
| Scheme | Use It For | Rules |
|---|---|---|
| Categorical | Teams, channels, products, routes, cohorts, or mutually exclusive groups. | Use five colors or fewer in one figure. Direct-label when possible. |
| Sequential | Rates, density, volume, percentiles, or ordered intensity. | Use one hue family with clear lightness steps. Do not use it for nominal groups. |
| Diverging | Above/below target, positive/negative change, forecast error, or margin from baseline. | Only use a diverging scale when the center has analytical meaning. |
| Semantic | Pass, warning, fail, missing, blocked, verified, or alert states. | Never rely on hue alone. Include labels or redundant encodings. |
| Highlight | One important segment, threshold, exception, annotation, or answer. | Make non-highlight marks neutral so the accent has a real job. |
Contrast Targets
Text and meaningful marks must survive on white, off-white, print, and low-quality displays. Use the higher contrast token for labels, annotations, and small marks.
Do And Do Not
- Use gray gridlines and axes so data marks read first.
- Use one accent for emphasis; do not decorate every figure with many saturated colors.
- Use color ramps only for ordered data.
- Use diverging color only when there is a meaningful center.
- Use labels, ordering, and proximity before relying on legend decoding.
- Do not use decorative gradients, rainbow scales, or color as the only carrier of meaning.