How to see an image as a color-blind person does
- Choose an image, or paste a screenshot with Ctrl+V.
- Look at the grid: normal vision, the four full types, and the milder "-anomaly" types at the severity you choose.
- Switch to One type, large to compare the original and the simulation with a slider.
- Download a single view as PNG, or all views on one sheet.
Roughly 1 in 12 men and 1 in 200 women have some color vision deficiency. Red-green types (deuteranomaly and protanopia) are by far the most common.
Method: Machado, Oliveira and Fernandes, "A Physiologically-based Model for Simulation of Color Vision Deficiency", IEEE Transactions on Visualization and Computer Graphics, 2009. Not affiliated with the authors.
Questions
Is my image uploaded?
No. The colors are changed by your browser on your device. Screenshots and designs stay private.
How accurate is the simulation?
It uses the matrices from Machado, Oliveira and Fernandes (2009), a widely used physiological model, applied in linear light. It is a good guide for checking contrast and color coding, but real vision varies from person to person and screens differ.
What do protanopia, deuteranopia and tritanopia mean?
They are missing or non-working red (protan), green (deutan), or blue (tritan) cones. The "-anomaly" versions, such as deuteranomaly, are a weaker form, which the severity slider shows. Achromatopsia is seeing no color at all.
Can I test a screenshot or a web page?
Yes. Take a screenshot, then paste it here with Ctrl+V (or Cmd+V), or choose the file. Check that charts, links, and status colors still work without relying on red versus green.
How do I design for color blindness?
Never rely on color alone. Add labels, patterns, or icons, keep strong contrast between light and dark, and avoid red and green next to each other as the only difference.
Credits
Built by OneTooling using standard browser features. No third-party code runs on your data.