See any image — your design, your chart, your photo — the way the 1 in 12 men and 1 in 200 women with color vision deficiency see it. Drag the slider to compare, check all eight types at a glance.
Roughly 1 in 12 men and 1 in 200 women have some form of color vision deficiency — that's about 350 million people, and statistically several of your users, students, or customers. If your chart encodes meaning as red-vs-green, your form marks errors only with color, or your map legend leans on subtle hue differences, part of your audience simply can't see what you're saying. This tool shows you exactly what they see instead — on your own image, in seconds.
Colors are transformed with the Machado, Oliveira & Fernandes (2009) simulation matrices — a peer-reviewed physiological model that's become the standard for this job. One detail matters a lot: the matrices are meant to operate in linear RGB, so this tool first undoes your image's gamma encoding, applies the transform, then re-encodes. Many quick simulators skip that step and produce washed-out, misleading results. The severity slider blends between normal vision and the full deficiency, approximating the milder anomalous forms most affected people actually have.
Drop in a screenshot of your chart, UI, or map and view it through research-grade simulations of eight vision types. The draggable before/after slider makes problem areas obvious, and the grid view shows every type at once.
Protanopia and deuteranopia are the red-green types, where reds and greens collapse toward similar muddy tones; deuteranopia is the most common. Tritanopia is the rare blue-yellow type. The simulator includes all three plus their milder forms and full monochromacy.
Roughly 1 in 12 men and 1 in 200 women have some form of color vision deficiency, which means a red-green status pair in your dashboard fails for about 8% of your male users.
Never rely on color alone: pair color with labels, patterns, shapes, or position. Test your palette here first; if your error-red and success-green collapse into the same shade in the deuteranopia view, add a second cue.
It uses the Machado 2009 physiologically-based model computed in linear RGB, the standard approach in vision research, with a severity slider for the milder anomalous forms.