A colorblind-friendly palette is the cheapest accessibility fix in data visualization. About 1 in 12 men and 1 in 200 women have some form of color vision deficiency, according to Colour Blind Awareness, so almost any chart with a legend reaches someone who cannot tell two of its colors apart. This guide covers which colors clash, a tested palette you can paste in, and the extra cues that make a chart work without color at all.
What is a colorblind-friendly palette?
A colorblind-friendly palette is a set of colors that stay distinguishable for people with the common types of color vision deficiency, mainly red-green. It works by varying lightness as well as hue, avoiding red against green, and using hues such as blue, orange and vermillion. It is paired with labels or shapes so color is never the only cue.
Who sees your chart differently
Color vision deficiency is usually inherited and far more common in men. Okabe and Ito's Color Universal Design page puts red-green color blindness at about 8% of men of European descent, 5% of men of Asian descent and 4% of men of African descent. The US National Eye Institute groups the types like this:
| Type | What gets confused | How common |
|---|---|---|
| Red-green (deuteranomaly, protanomaly, deuteranopia, protanopia) | Red with green, and shades of brown, orange and olive | The most common type; deuteranomaly is the most common of all |
| Blue-yellow (tritanomaly, tritanopia) | Blue with green, yellow with red or pink | Less common |
| Complete color blindness (monochromacy) | Most or all hues | Rare |
The practical takeaway: a chart that depends on telling red from green, the default traffic-light scheme on many dashboards, fails for the largest group.
One chart, seven colors, seven shapes
The chart below shows world population by region every five years from 1974 to 2024, using the World Bank's total population series. Seven lines is a hard test for any palette, and these lines cross: Sub-Saharan Africa grew from 328 million to 1.29 billion people and, in the World Bank's annual figures, overtook Europe & Central Asia in 2010.
It was built in PlotSet with the Line chart with shapes template, and it uses three of the techniques below at once:
- Okabe-Ito colors instead of the default palette, with yellow swapped for black because yellow lines vanish on white.
- A different marker shape per region, so two lines that look alike to a deuteranope are still easy to tell apart.
- A legend in the order the lines finish, from the largest region in 2024 to the smallest, so the eye moves straight from key to line.
Seven rules for colorblind-friendly charts
1. Never put red and green side by side
Red against green is the pair most people with color vision deficiency confuse. If you need "good" and "bad", use blue and orange, or blue and vermillion. Brown, olive and orange also collapse together for red-green viewers.
2. Vary lightness, not just hue
Two colors with the same lightness can look identical to a colorblind reader even when their hues differ. Pick colors that are clearly lighter or darker than their neighbours; a quick check is to view the chart in grayscale and see whether the series still separate.
3. Use a tested palette
The Okabe-Ito palette was designed to stay distinct for the common deficiencies:
| Name | Hex |
|---|---|
| Orange | #E69F00 |
| Sky blue | #56B4E9 |
| Bluish green | #009E73 |
| Yellow | #F0E442 |
| Blue | #0072B2 |
| Vermillion | #D55E00 |
| Reddish purple | #CC79A7 |
| Black | #000000 |
For ordered data such as a heatmap or a choropleth map, use a single-hue ramp from light to dark, or a perceptually uniform scale such as viridis, rather than a rainbow. For data with a meaningful midpoint, a blue-to-orange diverging scale works for most viewers.
4. Never rely on color alone
The W3C's accessibility guideline on use of color says color should not be the only way information is conveyed. On charts, that means direct labels on lines and bars, marker shapes or dash styles on line charts, and values printed on slices instead of a color-keyed legend.
5. Label directly where you can
A legend asks readers to match colors across the chart, which is the exact task colorblind readers find hardest. Put the name next to the line or inside the bar, and a legend becomes optional.
6. Meet the contrast minimums
WCAG asks for at least 4.5:1 contrast for normal text and 3:1 for meaningful graphics such as lines, bars and chart markers against their background (non-text contrast). Pale yellow or light grey lines on white usually fail.
7. Use fewer colors
Every extra series is another pair to confuse. Past six or seven categories, highlight the one or two that matter and grey out the rest, or split the chart. The chart chooser guide covers when a different chart type is the better fix.
How to test your chart
- Simulators. Coblis shows an uploaded image as people with each deficiency see it, and Color Oracle filters your whole screen in real time.
- Your browser. Chrome's DevTools can emulate vision deficiencies in the Rendering panel, which lets you check a live embed directly.
- Grayscale. Print or screenshot the chart in grayscale. If the series still separate, lightness is doing its job.
- Palette tools. ColorBrewer can filter its schemes to colorblind-safe ones for sequential, diverging and categorical data.
Applying it in PlotSet
Most PlotSet templates let you replace the default colors with your own palette in the chart settings, so you can paste the Okabe-Ito hex codes once and reuse them. For lines, the Line chart with shapes template adds a marker shape per series. For pie charts and bars, turn on value labels so each slice or bar is named in text, not only by color.
Frequently asked questions
What colors are best for colorblind people?
Blue and orange are the safest pair, because they differ in hue and lightness for every common type of color vision deficiency. The Okabe-Ito palette extends that to eight colors: orange, sky blue, bluish green, yellow, blue, vermillion, reddish purple and black.
What colors should you avoid for colorblind viewers?
Avoid red with green, and pairs that differ only slightly in lightness such as green with brown, blue with purple, or light green with yellow. These are the combinations most often confused.
Is a red-yellow-green traffic-light scheme accessible?
Not on its own. Red and green look similar to the largest group of colorblind viewers. Swap in blue and orange, or keep the colors but add text labels or icons so the status is readable without color.
How many colors can a chart use before it stops working?
Around six to eight distinct colors is the practical limit for categorical data, even with a well-designed palette. Beyond that, group small categories, highlight a few, or use small multiples.
Is viridis colorblind-friendly?
Yes. Viridis was designed to be perceptually uniform and to stay readable for common forms of color vision deficiency and in grayscale, which makes it a good default for heatmaps and maps.
