In this article
What Is Color Blindness?
Color blindness, or color vision deficiency (CVD), is a condition where certain colors are perceived differently or cannot be distinguished. The most common types affect red-green perception: protanopia (no red cones), deuteranopia (no green cones), and tritanopia (no blue cones). Achromatopsia, the rarest form, results in complete absence of color vision.
Approximately 8% of men and 0.5% of women have some form of color vision deficiency. For designers and developers, this means a significant portion of your audience may not see your UI, charts, or graphics the way you intended. A color blindness simulator lets you preview exactly what they see.
How the Simulator Works
The simulator applies scientifically validated color transformation matrices to every pixel in your image, modeling how each type of color vision deficiency alters color perception.
- LMS color space — pixel RGB values are converted to the LMS (Long, Medium, Short) cone response model that mirrors how human photoreceptors process light
- Machado 2009 matrices — the simulation uses matrices from the Machado, Oliveira & Fernandes (2009) research paper, which model cone response loss at configurable severity levels
- Canvas pixel transformation — each pixel is multiplied by the appropriate 3x3 matrix and converted back to RGB, producing an accurate preview of the image as seen by someone with that specific CVD type
Try it free — no signup required
Simulate Color Blindness →When To Use a Color Blindness Simulator
Testing your designs for color accessibility is essential for inclusive products and regulatory compliance.
- WCAG accessibility compliance — meet Web Content Accessibility Guidelines by ensuring information is not conveyed by color alone and that sufficient contrast exists for all users
- UI and UX design validation — check that buttons, alerts, status indicators, and navigation elements remain distinguishable for users with any type of color vision deficiency
- Data visualization — verify that charts, maps, heatmaps, and infographics use color palettes that remain readable and meaningful across all CVD types
Frequently Asked Questions
What is the most common type of color blindness?
Deuteranomaly (reduced green sensitivity) is the most common form, affecting approximately 6% of men. It causes difficulty distinguishing red from green and is often what people mean when they say "red-green color blind." Full deuteranopia (no green cones) is less common but more severe.
How do I design for color vision deficiency?
Use color plus another visual cue — icons, patterns, labels, or varying brightness. Avoid relying solely on red/green to signal success/failure; add checkmarks or text. Choose color palettes optimized for CVD (e.g., blue-orange instead of red-green). Always test your designs with a simulator before shipping.
Is color blindness the same as color weakness?
Color weakness (anomalous trichromacy) means one cone type has reduced sensitivity — colors appear shifted but are not completely absent. Color blindness (dichromacy) means one cone type is missing entirely, causing two colors to look identical. Monochromacy (achromatopsia) is the complete absence of color vision. A simulator can model all severity levels.