Color Blindness Simulator – See Images as Color Blind People Do
Check whether your charts, maps, UI designs and photos still work for the roughly 1 in 12 men and 1 in 200 women with colour vision deficiency. Drop an image and compare it with eight simulated types side by side.
Drop an image or screenshot and pick a type such as deuteranopia (no green) or protanopia (no red). The simulator shows the original next to the simulated version; “All types” shows all eight at once. It uses the Machado 2009 model in linear RGB, runs in your browser and lets you download the result as PNG.
How to use Color Blindness Simulator
- Drop an image, screenshot or design export.
- Choose a type of colour blindness.
- Compare the original with the simulation.
- Switch to “All types” to check every variant.
- Download the simulated image to share with your team.
Types of colour vision deficiency
Most colour blindness is inherited and affects the red and green cones in the eye. People with an “-opia” type are missing one kind of cone completely; with an “-anomaly” type the cone is present but shifted, so colours look weaker.
| Type | What is affected | Approx. share of men |
|---|---|---|
| Deuteranomaly | Weak green | 5 % |
| Protanomaly | Weak red | 1 % |
| Deuteranopia | No green cones | 1 % |
| Protanopia | No red cones | 1 % |
| Tritanopia / tritanomaly | Blue–yellow | under 0.01 % |
| Achromatopsia | No colour at all | very rare |
Red–green deficiencies are far more common in men because the genes sit on the X chromosome. Women are mostly carriers.
How the simulation works
The tool converts every pixel from sRGB to linear light, applies the colour matrices published by Machado, Oliveira and Fernandes (2009) and converts back. The anomaly types use a 60 % severity, which matches a typical mild-to-moderate deficiency. A simulation shows the information that is lost, not exactly what each person experiences — perception varies, and people learn to rely on brightness and context.
What to look for
Check whether elements that differ only by hue — red and green status dots, a green “profit” and red “loss” line, a heat map, map regions, or error text — become hard to tell apart. If two colours look almost the same in the deuteranopia and protanopia views, add a second cue: an icon, a label, a pattern, a different line style or a clear difference in lightness. Blue and orange is a much safer pair than red and green.
Design tips that help everyone
Good contrast between text and background matters even more than hue. Test text colours with the Color Contrast Checker, build palettes with enough lightness steps in the Color Palette Generator and pick colours from an existing design with the Color Picker from Image. WCAG 1.4.1 requires that colour is never the only way to convey information.
Private by design
Images are processed on a canvas in your browser and never uploaded. Large images are scaled to 1,600 pixels on the long side for speed.
You may also find these free tools useful: WebP to JPG Converter, Image Resizer and Image Compressor.
Frequently asked questions
What is the most common type of colour blindness?
Deuteranomaly, a weak sensitivity to green, affects about 5 % of men. Red–green types together affect about 8 % of men.
How accurate is the simulation?
It uses the widely cited Machado 2009 model. It shows which colour differences are lost, but individual perception varies.
Can I test a website?
Yes. Take a screenshot of the page and drop it into the simulator.
Which colours are safe for colour blind users?
Blue and orange work well. Also vary lightness and add labels or icons instead of relying on hue alone.
Are my images uploaded?
No. Everything runs locally in your browser.
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