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Nothing is uploaded. Just open it and start.

See your designs through colour-blind eyes

Around 1 in 12 men sees colour differently. Upload an image — a chart, a UI, a photo — or switch on your camera, and compare it side by side with how it looks under deuteranopia, protanopia, tritanopia, or total colour blindness. Everything runs in your browser. No sign-up, nothing uploaded.

Four vision types

Deuteranopia, protanopia, tritanopia, and total colour blindness, side by side with the original.

Adjustable severity

Slide from a mild anomaly to full dichromacy to see the whole range.

Image or live camera

Upload a design or turn on your camera to simulate the world in real time.

Private & client-side

Images and video are processed in your browser and never uploaded.

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Frequently asked questions

What does the colour blindness simulator do?
It transforms an image to approximate how someone with a colour vision deficiency sees it, placing the original and simulated versions side by side. It's a quick way to check whether a design, chart, or photo still reads clearly for the roughly 1 in 12 men and 1 in 200 women who see colour differently.
Which types can it simulate?
The three dichromacies — deuteranopia and protanopia (the two common red-green types) and tritanopia (blue-yellow) — plus achromatopsia, or total colour blindness, which shows the image in shades of grey. A severity slider lets you preview milder, anomalous versions too.
How accurate is it?
It uses the widely-cited Viénot–Brettel–Mollon simulation matrices applied in linear light, the same approach used by accessibility tools. It's a faithful approximation for design review, though individual experiences of colour blindness vary and no simulation is exact.
Can I check my webcam or a live view?
Yes. As well as uploading an image, you can switch on your camera to see the world around you simulated in real time. The video is processed entirely in your browser and never leaves your device.
Are my images uploaded?
No. Every image and camera frame is processed locally in your browser — nothing is uploaded or stored. It's free with no sign-up, and you can download the simulated image as a PNG.

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