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Color blindness simulator

Upload a screenshot, chart or photo to check it still works without full colour vision. The image is processed on this page and never uploaded.

Deuteranopia: no working green cones — the commonest form of red–green colour blindness.

Uses the Machado, Oliveira and Fernandes (2009) model at full severity, applied in linear RGB. Real colour vision varies from person to person — treat this as a design check, not a diagnosis.

About the color blindness simulator

See how an image looks to people with the main types of colour blindness: protanopia, deuteranopia, tritanopia and achromatopsia. Designers use it to check that charts, maps, buttons and status colours still make sense without full colour vision. The image is processed in your browser and never uploaded.

How to use it

  1. Choose an image: a screenshot, chart, photo or design mock-up.
  2. Pick a type of colour blindness.
  3. Compare the original and simulated versions side by side.
  4. Press “Download simulated PNG” to save the result.

Questions

What is the difference between protanopia and deuteranopia?
Both are red–green colour blindness. In protanopia the red-sensitive cones do not work, so reds also look darker; in deuteranopia the green-sensitive cones do not work. In both, reds and greens become hard to tell apart.
How accurate is this colour blindness simulation?
It uses the Machado, Oliveira and Fernandes (2009) model, a widely used research model, applied in linear RGB at full severity. Many colour-blind people have a milder form, so real perception varies; use it as a design check, not a diagnosis.
How do I make a chart readable for colour-blind people?
Do not rely on colour alone. Add labels, patterns or shapes, and avoid pairing red with green. Run the chart through the deuteranopia and protanopia views and check every series can still be told apart.
Is my image uploaded?
No. The image is read and processed with a canvas on this page, and the download is created on your device.