Simulador Daltonismo (Protanopia)

Color blindness simulator: design for the 8% you don't see

A color blindness simulator converts an image or a single color to show how a viewer with a color-vision deficiency perceives it. Roughly 8% of men and 0.5% of women have some form — that's hundreds of millions of users worldwide. Internally, simulators convert RGB into LMS color space (Long / Medium / Short wavelength cone responses), apply a 3×3 transformation matrix that models the missing or shifted cone, and convert back to RGB. The seminal references are the Brettel–Viénot–Mollon (1997) papers, still the basis of most modern simulators.

The types and their frequencies

• Protanopia — missing L (red) cone. ~1% of men.
• Deuteranopia — missing M (green) cone. ~1% of men; the most common dichromacy.
• Tritanopia — missing S (blue) cone. <0.01% — extremely rare.
• Anomalous trichromacy — cones present but shifted (protanomaly, deuteranomaly, tritanomaly). The most common form overall.
• Achromatopsia — no cones at all. Total color blindness; very rare.

WCAG compliance and design patterns

WCAG 2.1 success criterion 1.4.1 — "Use of Color" requires that color is never the only way to convey information. Practically that means: use icon + text + color for status (not color alone); avoid the red/green pair in critical state indicators (use blue/orange, which all dichromats can distinguish); maintain at least 4.5:1 contrast ratio for body text. Real-world precedents: F1 racing flags use distinct shapes as well as colors; Tokyo and NYC subway maps use colorblind-safe palettes and route letters/numbers as redundant cues.

Tools to add to your workflow

Beyond this simulator: Color Oracle (cross-platform desktop overlay), Sim Daltonism (Mac), Coblis (web), Stark (Figma / Sketch / Adobe XD plugin), Chromatic Vision Simulator (mobile, useful for live testing). Even better: Chrome DevTools (version 83+) has a built-in "Emulate vision deficiencies" toggle inside the Rendering panel — you can browse any site as a deuteranope without leaving the inspector.

Legal: ADA, EAA and beyond

In the United States the ADA (Americans with Disabilities Act) has been interpreted by courts to require web accessibility — Domino's, Target and many others have lost or settled lawsuits. The European Accessibility Act (EAA) becomes enforceable in June 2025 for digital products. In Brazil, the LBI (Lei Brasileira de Inclusão, 13.146/2015) and LGPD overlap on digital accessibility. Failing WCAG 1.4.1 because your dashboard's "OK / Error" indicator is only red vs. green is now both a UX defect and a legal exposure.

FAQ

Can I check whether my site is color-friendly? Yes — take screenshots of every critical screen (login, error, success, dashboard) and run them through the simulator for deuteranopia and protanopia. If you still understand the screen, you pass.

Does color blindness affect WCAG compliance? Yes — relying on color alone fails criterion 1.4.1 "Use of Color". Add icons, text or shape and you stay compliant.

Is this related to ADA / LGPD compliance? Yes — ADA case law and the upcoming EAA both treat WCAG conformance as the de-facto standard for digital accessibility, and color-only state communication is a recurring violation.

What's the safest color pair for accessibility? Blue and orange. All forms of dichromacy preserve the blue/yellow axis, so blue/orange remains distinguishable for nearly every viewer.