Color Blindness Simulator

How It Works

Each simulation type is a 3×3 matrix multiplied against the RGB triplet of every pixel, then blended with the original at your chosen intensity. The matrices are the commonly published linear approximations of the Viénot–Brettel–Mollon transforms (with Machado's severity-0.5 table for mild deuteranomaly): they are a shortcut around the full nonlinear cone-projection algorithms, which is honest but means extreme saturated colors can differ slightly from a lab-grade simulation. Everything runs on a local canvas — no upload.

Which cone each type lacks

Normal trichromatic vision uses L (long), M (medium) and S (short) wavelength cones. Deuteranopia removes the M cones, so reds and greens collapse onto a shared axis; protanopia removes the L cones, with the same red-green confusion but darker reds; tritanopia removes the S cones and confuses blue with green and yellow with pink; achromatopsia leaves only one working response and reduces the world to lightness.

How common each type is

Roughly 8% of men and 0.5% of women of Northern European descent have some red-green deficiency — deuteranomaly being the most frequent single type. Protanopia sits near 1–2% of men. Tritanopia is rare (well under 0.01%, and not sex-linked), and complete achromatopsia affects about 1 in 30,000. Prevalence is lower in many other populations, but red-green confusion remains the dominant design constraint worldwide.

What this means for UI design

Never encode meaning in hue alone. A success/error pair that only differs green-vs-red is unreadable to about 1 in 12 male users; pair it with an icon, a label or a lightness step. The same rule covers charts (adjacent series colors), map legends and status dots. If a design still communicates after a deuteranopia pass, it usually survives every other deficiency too.

Frequently Asked Questions