👁️ Color Blindness Simulator
See how an uploaded image or a pasted palette appears to people with color-vision deficiency — the four main types, with an adjustable severity — 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 color blindness simulator works
The tool converts each pixel or swatch to linear-sRGB and applies the published Machado, Oliveira & Fernandes (2009) transform matrices for protanopia, deuteranopia and tritanopia (and a luminance projection for achromatopsia), then converts back to sRGB. The severity slider interpolates between your original and the full-dichromat simulation to approximate anomalous trichromacy. Images are drawn to a canvas and never uploaded; palettes are simulated swatch-by-swatch.
About 1 in 12 men and 1 in 200 women have some color-vision deficiency. The palette mode is the differentiator — you can test the exact swatches in a design system, not just a screenshot — and everything runs on-device, so unreleased designs stay private.
Frequently asked questions
What types of color blindness can I simulate?
The four main types: deuteranopia (green-weak, the most common), protanopia (red-weak), tritanopia (blue-weak), and achromatopsia (total, seeing only lightness). A severity slider approximates the milder "anomalous" forms of each.
How accurate is the simulation?
It uses the Machado, Oliveira & Fernandes (2009) matrices — the field-standard published constants also used by scientific tools — applied in linear-sRGB. Simulations are close approximations of average CVD perception, not a substitute for testing with real users.
Can I test a color palette, not just an image?
Yes. Paste a list of colors and the tool simulates each swatch under the selected deficiency, so you can check whether two palette colors become indistinguishable — the key design-system question.
Is my image uploaded anywhere?
No. The image is drawn to a canvas and processed pixel-by-pixel in your browser; it never leaves your device, which matters for unreleased work.
Why do some colors look the same after simulation?
That is the point — if two colors collapse to nearly the same appearance under, say, deuteranopia, a color-blind user cannot tell them apart. Add a non-color cue (text, icon, pattern) or increase their lightness difference.