Color Blindness Simulator

Knowledge Base

Why This Matters for Thumbnails and Graphics

Roughly 1 in 12 men and 1 in 200 women have some form of colour vision deficiency: for a channel with any meaningful reach, that's a real slice of your audience seeing a different version of every thumbnail and graphic you publish. A design that relies purely on a red/green distinction (a common failure) can become illegible or confusing for these viewers.

The Three Types Simulated Here

• Protanopia: Missing red-sensing cones, reds appear darker and can be confused with dark greens or browns.
• Deuteranopia: Missing green-sensing cones. The most common form. Reds and greens both shift toward similar yellowish-brown tones.
• Tritanopia: Missing blue-sensing cones, rare. Blues and yellows become the hardest to distinguish.

Designing Around It

Pair colour with a second signal (contrast, shape, or text label) rather than colour alone to convey meaning. Check your thumbnail's text/background contrast independently with the Contrast Checker (WCAG). Strong luminance contrast reads clearly across all colour vision types even when hue distinctions are lost.

FAQ

Q: Is this simulation clinically accurate?
A: It uses simplified, widely-used approximation matrices applied directly to standard RGB values. A solid practical check for design purposes, not a substitute for clinical colour vision testing.

Q: Which type should I prioritise checking for?
A: Deuteranopia is the most common form by a wide margin, so if you only check one, check that, but all three take seconds to review here.