Color Blindness Simulator

About 1 in 12 men and 1 in 200 women have some form of color-vision deficiency, most often a weak or missing red or green cone type. This simulator shows how a picture or a color palette looks with protan (red), deutan (green) and tritan (blue) deficiencies and with achromatopsia, from mild to complete. For palettes it also finds the pair of colors that becomes hardest to tell apart, so you can fix charts, maps and interfaces before they reach users.

How to use this tool

1. Choose one or more images, and/or type your colors one per line.
2. Pick a deficiency type or keep "All four types".
3. Set the severity: 100% for the complete forms, lower for the milder, more common forms.
4. Compare the simulated images and the palette table; check the hardest pair to tell apart.

Formula

simulated = M(type, severity) × [R, G, B] in linear-light sRGB, then gamma-encoded again

M is the 3 × 3 matrix published by Machado, Oliveira & Fernandes (2009) for each type in 10% severity steps; values in between are interpolated. Achromatopsia replaces each pixel with its luminance Y = 0.2126 R + 0.7152 G + 0.0722 B.

Example

Pure red #FF0000 becomes the dull olive #6D5F00 with protanopia, the mustard #A39000 with deuteranopia, stays almost red (#FF000F) with tritanopia, and turns mid-gray #7F7F7F without color vision. At 50% severity (protanomaly) the same red looks like #B45600. In the default five-color palette, deuteranopia turns #E9C46A and #F4A261 into the close yellows #DFCC6D and #CEBC61 — their difference drops from ΔE2000 15.3 to 4.1, the hardest pair in the set.