Color Blindness Simulator
See any image as protanopia, deuteranopia or tritanopia sees it.
About this simulator
Drop in a screenshot, chart or photo and flip between vision types โ the two red-green dichromacies, rare tritanopia, and full monochrome โ using the standard simulation matrices, computed on your device. Download any view for a bug report or design review.
Designing for the twelfth user
Roughly 8% of men (and 0.5% of women) have a colour vision deficiency โ overwhelmingly red-green โ meaning a mostly-male user base has a colour-blind user in every dozen. The failure pattern is always the same: meaning carried by hue alone โ red/green status dots, line charts distinguished only by colour, heat maps. The fix is redundancy, not colour abstinence: pair hue with icons, labels, position or pattern, and check that your "success" and "error" states survive the deuteranopia view (they usually don't on the first try). Honest note: these matrices are the standard published approximations of dichromacy โ real perception varies by person and severity. The other half of visual accessibility is contrast โ the contrast checker handles that โ and palette extraction helps rebuild schemes that survive both.
Frequently asked questions
What's the most common type of color blindness?
Red-green, split between deutan (green-cone) and protan (red-cone) types โ together about 8% of men. Tritanopia (blue-yellow) and full monochromacy are far rarer.
Why do my red and green status dots fail the simulation?
Under red-green deficiency both converge on muddy yellow-browns โ the exact colours chosen to mean opposite things become twins. Add icons or labels; colour can emphasise but shouldn't be the only channel.
How accurate is the simulation?
It uses the standard published matrices for full dichromacy โ a good approximation of the severe case. Real-world deficiency spans a spectrum, so treat it as a stress test, not a per-person prediction.
Is my image uploaded?
No โ the matrix runs on a canvas in your browser; nothing leaves your device. Free, no account.