What are the types of color blindness?

The common inherited forms: deuteranopia and protanopia (both collapse red-green, together about 8% of men), tritanopia (blue-yellow, rare), and achromatopsia (no hue at all, very rare). The simulator renders all of them plus the milder -anomaly variants.

How do I check if my palette is color-blind safe?

Paste the palette or upload an image and read the simulated rows: if two colors that carry different meanings merge in any row, add a lightness difference, a label, or a pattern. The achromatopsia row is the strictest test: if it reads there, it reads for everyone.

How accurate is the simulation?

It uses the Machado 2009 physiologically-based model, applied in linear light, the same approach professional design tools use. It approximates typical cases of each deficiency; individual vision varies.

Is red and green always a problem?

Only when hue is the only difference. A dark red against a light green survives red-green deficiency because the lightness gap carries the meaning. The contrast checker can widen that gap for any failing pair.

Color blindness simulator

Roughly 1 in 12 men and 1 in 200 women see color differently. Paste a palette or upload an image to see it through the three common types of color blindness, plus full color blindness.

How this works

1 Pick a color or upload an image.
2 See it the way eight kinds of color vision see it.
3 Use the side-by-side views to check your palette still works for everyone.

Simulator

Check a palette

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Normal vision ↑

Protanopia (no red). Missing long-wavelength (red) cones. Reds darken and red-green pairs collapse. About 1% of men.

Deuteranopia (no green). Missing medium-wavelength (green) cones. The most common type: red and green become hard to separate. About 1% of men.

Tritanopia (no blue). Missing short-wavelength (blue) cones. Blue and yellow confuse. Rare, and affects all genders about equally.

Achromatopsia (no color). No color at all, only lightness. Very rare. A palette that still reads here is as resilient as it gets.

Simulator

Check an image

Images are processed on your device and never uploaded.

Guide

Designing for color vision deficiency

The most common trap is encoding meaning in red versus green alone, since deuteranopia and protanopia collapse exactly that pair. The fix is not to avoid those colors but to add a second signal: a difference in lightness, a label, an icon, or a pattern. If a chart still reads in the achromatopsia row above, where all hue is gone, it will read for everyone.

These simulations use the Machado 2009 model, the same one many professional tools use, applied in linear light for accuracy. To fix a failing pair, the contrast checker can raise the lightness gap between two colors until they separate even without hue.

FAQ

Common questions

What are the types of color blindness?: The common inherited forms: deuteranopia and protanopia (both collapse red-green, together about 8% of men), tritanopia (blue-yellow, rare), and achromatopsia (no hue at all, very rare). The simulator renders all of them plus the milder -anomaly variants.
How do I check if my palette is color-blind safe?: Paste the palette or upload an image and read the simulated rows: if two colors that carry different meanings merge in any row, add a lightness difference, a label, or a pattern. The achromatopsia row is the strictest test: if it reads there, it reads for everyone.
How accurate is the simulation?: It uses the Machado 2009 physiologically-based model, applied in linear light, the same approach professional design tools use. It approximates typical cases of each deficiency; individual vision varies.
Is red and green always a problem?: Only when hue is the only difference. A dark red against a light green survives red-green deficiency because the lightness gap carries the meaning. The contrast checker can widen that gap for any failing pair.