Preview a colour or an uploaded image under four colour-vision-deficiency simulations: protanopia, deuteranopia, tritanopia and achromatopsia.
How the picked colour appears under each simulation:
Images are processed on this device only. For speed, large images are scaled to a maximum width of 900 pixels before the simulation runs.
Each simulation applies a standard colour-vision-deficiency transformation matrix to every pixel: protanopia (no red cones), deuteranopia (no green cones), tritanopia (no blue cones) and achromatopsia (no colour vision, luminance only). The same matrices drive the single-colour swatches, so a brand colour can be checked quickly before an image is tested. Simulations are approximations of how a design may appear, not a medical assessment, and contrast and labelling should never rely on colour alone.
What types of colour blindness are simulated? Protanopia, deuteranopia, tritanopia and achromatopsia, using standard transformation matrices applied to each pixel or to the picked colour.
Is the uploaded image sent anywhere? No. The image is read and processed locally on the device, scaled to a maximum width of 900 pixels for speed, and never uploaded.
Is a simulation exact? No. Colour-vision deficiency varies between individuals, so a simulation is a guide for spotting colours that become hard to tell apart, not a guarantee of how any one person sees a design.