Colorblind Simulator — Preview Your Images

Color vision deficiency, commonly called color blindness, is a condition where certain cone cells in the retina do not function normally. This makes it harder to distinguish between specific colors. About 8% of men and 0.5% of women have some form of CVD.

Protanopia means the red cone cells are absent (red-blind), while deuteranopia means the green cone cells are absent (green-blind). Both are red-green color blindness, but protanopia also causes red colors to appear darker. Deuteranopia is the most common type.

Most people with color vision deficiency have anomalous trichromacy — their cone cells work, but with shifted sensitivity. The severity slider lets you simulate the full spectrum from mild anomaly (e.g., deuteranomaly) to complete dichromacy (e.g., deuteranopia).

Daltonize is a technique that takes the color information lost in a particular type of color blindness and shifts it into color channels that the person can still see. It helps colorblind viewers distinguish colors they would otherwise confuse.

About 1 in 12 men has some form of color vision deficiency. If your website, app, or infographic relies on color alone to convey information, a significant portion of your audience may miss important details. Testing with a simulator helps you create more accessible designs.

Usually they see rather more. The transformations here model dichromacy — the complete absence of one cone type — because that is the case that can be computed exactly. But most people with a color vision deficiency are anomalous trichromats: the cone is present and shifted, not missing, so they retain some of the discrimination the simulation removes. Treat the result as the worst case rather than the typical one. That is exactly what makes it useful for design: a chart that still reads under this simulation reads for everyone, and one that collapses here will be hard for a real range of people, even if none of them sees quite what you are looking at.