🔴 Protanopia Simulator
See how an image or palette looks with protanopia, a red-weak color-vision deficiency — all processed on your device.
Choose an image to see the original and simulated versions side by side. It never leaves your device.
Machado, Oliveira & Fernandes (2009) matrices in linear-sRGB. Approximates average CVD perception. 🔒 Images processed on-device, never uploaded.
How the protanopia simulator works
Each pixel or swatch is linearised and multiplied by the published Machado (2009) protanopia matrix, then converted back to sRGB, with a severity slider for milder protanomaly. Images are processed on a canvas and never uploaded.
Protanopia (red-weak) darkens reds and confuses them with greens and browns. Because reds appear dimmer, red warning text on a dark background can nearly vanish — worth testing directly.
Frequently asked questions
What is protanopia?
Protanopia is a red-green color-vision deficiency where the red-sensitive (L) cones are absent. Reds look darker and are easily confused with greens, browns and blacks.
How is it different from deuteranopia?
Both are red-green deficiencies, but protanopia specifically dims reds (red appears much darker), whereas deuteranopia affects greens more and keeps brightness closer to normal.
What should I check for?
Red text or icons on dark backgrounds (they can become very low-contrast) and any red/green distinction. Add non-color cues where meaning depends on red.
Is my image private?
Yes — it is processed on a canvas in your browser and never uploaded.
Can I adjust severity?
Yes — the slider interpolates toward full protanopia to approximate protanomaly (partial red-weakness).