Color Blindness Simulator

A documented display-color model

Colorrow uses the 100% protanopia, deuteranopia, and tritanopia matrices published with the Machado, Oliveira, and Fernandes color-vision-deficiency model. sRGB values are converted to linear-light RGB before the matrix transform, then encoded back for display.

This is a simulation of how color relationships can change on a display. It is not a medical test, diagnosis, or prediction of exactly what any individual person sees.

Compare separation, not just hue names

Watch for two statuses, chart series, buttons, or map regions that become difficult to tell apart after simulation. A red/green pair can be risky, but the actual problem is whether meaning depends on a color distinction that becomes weak.

Palette simulation is especially useful before assigning semantic roles. Image simulation helps expose legends, badges, overlays, and diagrams that may rely on color alone.

Give important states a second signal

• Pair status colors with text labels or recognizable icons.
• Use patterns, shapes, line styles, or direct labels in charts and maps.
• Keep links, focus states, errors, and selected controls identifiable without hue alone.
• Check contrast separately; colors that remain distinguishable can still be unreadable.

Simulation cannot certify accessibility

Color vision varies across people and viewing conditions. Display calibration, brightness, surrounding colors, and severity all affect perception. This tool uses full dichromacy matrices as a repeatable stress test rather than claiming to reproduce every form or severity of color vision deficiency.

A simulated image also cannot tell you whether labels are understandable, keyboard focus is visible, or an entire product meets WCAG. Treat it as one part of a broader accessibility review.

Large files are reduced before pixel simulation

Files are validated before decode. Images above the preview budget are proportionally downscaled to at most 1,800 pixels on either side and about two million processed pixels. This keeps side-by-side previews responsive without changing the original file on disk.

Transparency is preserved. The simulator transforms RGB channels and leaves each pixel's alpha channel unchanged.

Follow simulation with exact checks

Use simulation to spot risky distinctions, then check exact foreground/background contrast and test the palette in realistic components. Accessibility comes from redundant cues, readable contrast, understandable content, interaction states, and real user context—not from one simulated screenshot.