Simulate how images and designs appear to people with color vision deficiencies. Apply protanopia, deuteranopia, tritanopia, and achromatopsia filters to uploaded images or the built-in test pattern.
Upload an image or use the built-in test pattern below
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How to use Color Blindness Simulator
Use the built-in rainbow test pattern or upload your own image (design mockups, photos, charts, or UI screenshots work best).
Click through the CVD type tabs (Protanopia, Deuteranopia, Tritanopia, Achromatopsia) to see how each type affects the image.
Toggle Split View to compare original vs simulated side-by-side on the same canvas.
Use the Blend slider to dial in a partial effect (useful for understanding borderline cases).
What is Color Blindness Simulator?
Approximately 8% of men and 0.5% of women have some form of color vision deficiency (CVD). This tool uses LMS (Long/Medium/Short cone) color space transformations to accurately simulate how images appear to people with different types of color blindness.
Protanopia (red-blind, ~1% of males): Missing L cones — reds appear dark, confusion between red/green and blue/purple.
Deuteranopia (green-blind, ~1% of males, most common): Missing M cones — similar to protanopia but colors don't appear as dark.
Tritanopia (blue-blind, very rare): Missing S cones — blues appear greenish, yellows appear pinkish.
Achromatopsia (total color blindness, extremely rare): No cone function — only sees grayscale.
Use the Split View to compare original and simulated side-by-side, or adjust the Blend slider to see partial CVD effects.
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FAQ
How accurate is this simulation?
The simulation uses the standard LMS cone-space transformation method (linear RGB to LMS, zeroing the deficient cone response, converting back). This is the same mathematical model used by accessibility tools and academic research. It accurately represents dichromatic color vision (missing one cone type) but cannot perfectly simulate anomalous trichromacy (shifted cone sensitivity).
Why would I use this for design?
Designers use CVD simulators to ensure charts, UIs, maps, and graphics remain distinguishable to color-blind users. For example, red-green traffic light indicators become indistinguishable with protanopia/deuteranopia — you would add shape or text labels as a fallback.
What is the difference between protanopia and deuteranopia?
Protanopia means the L (long-wavelength/red) cones are missing, causing reds to appear much darker. Deuteranopia means the M (medium-wavelength/green) cones are missing, causing similar red-green confusion but with normal brightness perception. The simulation filters produce subtly different results, especially in the red/magenta range.
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