Color Blindness Simulator

Color blindness (color vision deficiency) affects approximately 8% of males and 0.5% of females worldwide. The condition arises from missing or malfunctioning cone cells in the retina. Human eyes have three types of cones sensitive to red, green, and blue light. When one or more cone types are absent or dysfunctional, colors in that range appear muted or indistinguishable from neighboring hues.



This simulator applies mathematical color transformation matrices to your uploaded image, converting the full-color image into how it would appear with each type of color blindness. The transformations are based on established research by Viénot, Brettel, and Mollon, which model how the visual cortex processes signals from affected cone types.



Deuteranopia (green-blind) is the most common form, affecting ~6% of males. Protanopia (red-blind) affects ~2% of males. Tritanopia (blue-blind) is rare, affecting less than 0.01% of the population. Achromatopsia (complete color blindness, seeing only grayscale) is extremely rare. All processing happens locally in your browser using the Canvas API—images are never uploaded to any server.

1. UI/UX Design Accessibility Testing
Designers use color blindness simulation as a mandatory step before releasing products. A button that uses red text on a green background may be perfectly readable for most users but completely invisible to someone with deuteranopia. Testing your interface ensures all users can interact with it effectively, regardless of their color vision.



2. Data Visualization Review
Charts, graphs, and infographics often use color as the primary differentiator between data series. A pie chart with red and green segments becomes a single color for deuteranopic viewers. Simulating your visualizations helps you identify which colors need additional differentiation—patterns, textures, or labels—to remain meaningful for all audiences.



3. Marketing Material Validation
Brand colors, call-to-action buttons, and promotional materials reach audiences with diverse vision capabilities. Simulating your marketing assets helps ensure that key messages aren't lost on a significant portion of your audience. Red "sale" tags that blend into green backgrounds, for example, would be missed by 8% of male shoppers.



4. Digital Accessibility Compliance
WCAG 2.1 guidelines require that color alone is not used to convey information. Organizations subject to ADA, Section 508, or European Accessibility Act compliance need to test their interfaces. This simulation provides visual evidence that your design doesn't rely solely on color to communicate meaning.



5. Educational Awareness
Educators, designers, and developers who don't have color blindness themselves can use this tool to build genuine empathy for users who do. Understanding how the world appears to color-blind individuals helps create more inclusive designs and fosters appreciation for universal design principles.

• Test with all major types: Don't just check deuteranopia—test protanopia and tritanopia too. Different color deficiencies affect different parts of the color spectrum, and your design may pass one but fail another.



• Use patterns and labels, not just color: If simulations reveal problem areas, fix them by adding patterns, borders, textures, or direct labels rather than just adjusting hue. This creates redundant coding that works for everyone.



• Check contrast ratios alongside simulation: Use this tool alongside a color contrast checker to catch both visibility and legibility issues. Simulating color blindness shows which colors blur together; contrast ratios show whether text is legible.



• Test your actual screenshots: Don't test generic stock images—take real screenshots of your UI and test those. Edge cases in your specific design may not be obvious until you see them through a simulation.



• Avoid red-green combinations entirely: Since deuteranopia and protanopia are the most common forms, avoiding pure red/green combinations as the only distinguishing feature is the single most impactful change you can make.



• Pay special attention to alerts and status indicators: Traffic lights, error/success states, and warning indicators are especially prone to color-blindness issues. These are high-stakes UI elements where misinterpretation has real consequences.