Color Blindness Simulator
Preview any color or palette under seven types of color vision deficiency. Test whether your design communicates without relying on color alone.
Understanding color vision deficiency
Color vision deficiency (CVD) describes any condition in which a person sees colors differently from the majority. It is caused by differences in the cone cells of the retina — the cells responsible for detecting red, green and blue light.
| Type | Description | Approx. prevalence (males) |
|---|---|---|
| Protanopia | Red-blind — red appears black | ~1% |
| Protanomaly | Red-weak — reds appear muted | ~1% |
| Deuteranopia | Green-blind — greens appear brownish | ~1% |
| Deuteranomaly | Green-weak — most common form | ~5% |
| Tritanopia | Blue-blind — blues appear greenish | <0.01% |
| Tritanomaly | Blue-weak — blue-yellow confusion | <0.01% |
| Achromatopsia | Complete absence of color vision | ~0.003% |
How the simulation works
Each CVD type is modeled by a 3×3 matrix applied to linear sRGB values. The matrices used here come from Machado, Oliveira & Fernandes (2009) at full severity. The pipeline is:
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sRGB → linearEach channel is delinearized using the sRGB transfer function so that the matrix operates in a physically meaningful space.
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Apply the CVD matrixThe three linear channels are mixed according to the type of deficiency. This is what changes the perception of reds, greens or blues.
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Linear → sRGBThe result is converted back to displayable sRGB, clamped to the 0–255 range.
Designing for color vision deficiency
- Never use color alone to convey meaning. Pair color with icons, labels, patterns or position.
- Prefer distinguishable lightness differences between adjacent colors over hue differences.
- Test your red/green status indicators — they are the most common failure point.
- Ensure focus states and error indicators remain visible in grayscale.
- For data visualization, use shape, texture or direct labels in addition to color.
Frequently asked questions
Is the simulation accurate?
The simulator uses published scientific matrices applied in linear light. It is a good approximation, not a medical-grade diagnostic. Individuals with the same condition may perceive colors slightly differently.
Do I need to worry about all seven types?
Red-green deficiencies (protan and deuteran variants) are by far the most common and affect the largest audience. Testing those first, then achromatopsia, is a good prioritization.
Can this test whether I am colorblind?
No. This is a designer-facing simulator, not a medical test. If you suspect you have color vision deficiency, consult an optometrist or ophthalmologist for a proper Ishihara or equivalent test.
Does my image get uploaded?
No. All simulation happens locally in your browser — no colors, palettes or images are sent to any server.