Upload an image and preview how it looks with protanopia, deuteranopia, or tritanopia — useful for checking that charts, maps, and UI don't rely on color alone. Nothing is uploaded anywhere.
Click or drop an image here
Normal vision
Protanopia (red-blind)
Deuteranopia (green-blind)
Tritanopia (blue-blind)
How it works
Each pixel's RGB values are multiplied through a fixed 3×3 matrix (from Machado, Oliveira & Fernandes' 2009 research) that maps normal color perception onto what someone with protanopia, deuteranopia, or tritanopia would see, applied directly to the canvas's ImageData pixel array via the browser's Canvas 2D API. The whole thing runs locally — your image is loaded into a canvas from a local object URL and never leaves your device.
FAQ
Does this simulate every kind of color blindness?
No — it covers the three dichromatic (fully color-blind) forms: protanopia (red), deuteranopia (green), and tritanopia (blue). It doesn't simulate anomalous trichromacy (the far more common milder color weakness) or total color blindness (achromatopsia).
Is this simulation scientifically accurate?
It uses a well-established published matrix (Machado/Oliveira/Fernandes 2009) applied to standard sRGB values rather than a made-up approximation, though like any single-matrix model it's a simplification of how individual color vision actually varies.
Free, unlimited, no account. If this saved you a paid tool, a small thanks is appreciated.