Color Blindness Simulator for Colour Palettes
Simulate colour vision deficiencies on a palette, with clash warnings.
No green cones. Red and green look alike; the most common dichromacy.
Colours
About 2 is just noticeable side by side; 5 is a sensible minimum for chart series and legend dots.
| Original | Deutan |
|---|---|
| #e53935 | #98892e |
| #43a047 | #978a4e |
| #1e88e5 | #377de3 |
| #fdd835 | #f9df41 |
| #8e24aa | #2a5ca7 |
- #e53935 and #43a047 are hard to tell apart (ΔE 0.030, was 0.312).
Use via API
Simulate how a list of colours looks with each colour vision deficiency (Machado 2009 model) and flag pairs that become hard to tell apart for one chosen type. Colours only, not images. Send JSON, get JSON back.
POST https://pithlab.com/api/v1/tools/color-blindness-simulator
curl https://pithlab.com/api/v1/tools/color-blindness-simulator \
-H "Authorization: Bearer $PITHLAB_KEY" \
-H "Content-Type: application/json" \
-d '{"colors":"#d62728, #2ca02c, #1f77b4","type":"deuteranopia"}'About the Color Blindness Simulator
See your colour palette as people with protanopia, deuteranopia, tritanopia, weaker anomalies or achromatopsia do, and spot colours that become hard to tell apart.
How to use the Color Blindness Simulator
- Choose a type of colour vision deficiency. For protanomaly, deuteranomaly and tritanomaly, set how severe it is.
- Enter a list of colours, such as your chart or brand palette, to see each one's simulated hex value for every type.
- Read the warnings: pairs whose simulated colours are closer than the ΔE threshold are hard to tell apart and need another cue, like a label, pattern or lightness difference.
Examples
Input
#ff0000, protanopia
Output
#ff0000 → #6d5f00; all distinguishable
Input
#e53935, #43a047, #1e88e5, deuteranopia
Output
#e53935 → #98892e, #43a047 → #978a4e, #1e88e5 → #377de3; hard to tell apart: #e53935 and #43a047 (ΔE 0.030)
Input
#808080, #ffffff, achromatopsia
Output
#808080 → #808080, #ffffff → #ffffff; all distinguishable
Frequently asked questions
Which simulation model does this use?
The physiologically based model of Machado, Oliveira and Fernandes (2009), using their full-severity matrices in linear-light sRGB. For the -anomaly types the tool blends that matrix with normal vision at your chosen severity, which approximates Machado's intermediate tables to within a few percent.
How common is colour blindness?
About 8% of men and 0.5% of women of Northern European descent have red-green colour vision deficiency, mostly deuteranomaly. Tritan deficiencies affect roughly 1 in 10,000 people, and complete achromatopsia about 1 in 30,000.
What does the ΔE threshold mean?
ΔE OK is the distance between two colours in the OKLab colour space. About 0.02 is just noticeable side by side; the default of 0.05 flags pairs that are hard to tell apart in small areas such as chart lines or legend dots.
Is anything uploaded?
No. The simulation runs in your browser, and the colours you enter never leave your device.
How do I fix colours that clash?
Make them differ in lightness, not just hue, and never rely on colour alone: add labels, icons, patterns or line styles. Blue and orange are a safer pair than red and green for most people.