What it does
Open, drop or paste an image (a screenshot from your clipboard works) and see it through seven types of colour vision deficiency at once:
- Protanopia / protanomaly: missing or weak red-sensitive cones.
- Deuteranopia / deuteranomaly: missing or weak green-sensitive cones.
- Tritanopia / tritanomaly: missing or weak blue-sensitive cones.
- Achromatopsia: no colour vision, only brightness.
Pick a type to compare it with the original using the slider: drag across the image or use the arrow keys on the slider. Download any simulation as a full-size PNG, or all of them at once.
How it works
The simulation uses the matrices from Machado, Oliveira and Fernandes (2009), A Physiologically-based Model for Simulation of Color Vision Deficiency: severity 1.0 for the -opia types and 0.6 for the -anomaly types. Pixels are converted from sRGB to linear RGB before the matrix is applied and back afterwards, because the model is defined on linear light; applying it to gamma-encoded values distorts the result. Achromatopsia uses the Rec. 709 luminance weights.
Large images are scaled down for the on-screen preview so the page stays fast; downloads are processed at the original resolution (up to 40 megapixels).
Tips
Check that information is never carried by colour alone: status pills, chart series and error states should also differ in shape, label, pattern or brightness. The example dashboard shows how red/green pairs collapse for protan and deutan viewers.
Privacy
Images are processed on a canvas in your browser and never uploaded.