Color Blindness Simulator
Upload an image and see how it is perceived under protanopia, deuteranopia, tritanopia or achromatopsia — compare before/after and download the result as a PNG.
About color blindness
Color vision deficiencies change how the eye's cone cells respond to certain wavelengths, making some colors hard to tell apart. This tool approximates that perception by running every pixel through the matching 3x3 color transform matrix; for achromatopsia all channels collapse to the same gray value. It is handy for checking whether your designs stay accessible, and it runs entirely in your browser.