Color Blindness Simulator
Private by design — runs entirely in your browser
See how a colour will look to people with the three common types of dichromacy, plus full grayscale. Helps catch palettes that lose meaning without colour.
How are the simulations computed
Each output is a linear-RGB transformation matrix from the Brettel/Viénot/Mollon dichromat model, applied to your input colour. The result is an approximation, not a clinical reproduction.
Why also achromatopsia
Achromatopsia (full colour blindness) is rare but checking against it gives you a quick monochrome view that exposes palettes that rely purely on hue rather than luminance contrast.
What should I do with the swatches
Compare neighbouring swatches across the four simulations. If two swatches look identical in any column, that palette needs a non-colour difference (icon, label, pattern).
Frequently Asked Questions
- How are the simulations computed?
- Each output is a linear-RGB transformation matrix from the Brettel/Viénot/Mollon dichromat model, applied to your input colour. The result is an approximation, not a clinical reproduction.
- Why also achromatopsia?
- Achromatopsia (full colour blindness) is rare but checking against it gives you a quick monochrome view that exposes palettes that rely purely on hue rather than luminance contrast.
- What should I do with the swatches?
- Compare neighbouring swatches across the four simulations. If two swatches look identical in any column, that palette needs a non-colour difference (icon, label, pattern).
- Is anything uploaded?
- No. The matrix multiplications happen in JavaScript on this page; nothing leaves the browser.