👁️ 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.