Free Image Accessibility Tool
Color Blindness Simulator for Images
Upload any image and instantly see how it appears to people with different types of color vision deficiencies.
Upload an Image
Drag and drop your image here, or click to browse
Supports JPG, PNG, GIF, WebP, SVG, BMP (max 10MB)
What This Tool Does
This tool shows you exactly how your images look to people with different types of color blindness. It’s not just slapping a filter on—we're simulating what actually happens when certain cone cells in the retina are missing or work differently.
Upload any image and we’ll run it through color transformation formulas derived from real vision science research. The result? An accurate preview of how someone with that specific type of color blindness would see your work.
If you design interfaces, marketing materials, data visualizations, or really anything visual—this lets you catch problems before they hit production. Way better than finding out later that your red and green buttons look identical to 8% of your users.
Supported Color Deficiencies
Protanopia & Protanomaly
Red color blindness. Protanopia involves complete absence of red cones, while protanomaly involves anomalous red cones. Affects approximately 1% of males.
Deuteranopia & Deuteranomaly
Green color blindness. Most common form, affecting 5-6% of males. Deuteranopia means no green cones, deuteranomaly means defective green cones.
Tritanopia & Tritanomaly
Blue-yellow color blindness. Very rare, affecting less than 0.01% of the population. Involves absent or defective blue cones.
Achromatopsia & Achromatomaly
Complete or near-complete color blindness. Achromatopsia involves seeing only in grayscale. Extremely rare, affecting about 1 in 30,000 people.
How the Simulation Works
Quick biology lesson: your eyes have three types of cone cells that detect red, green, and blue light. When all three work normally, your brain mixes those signals together to create the full color spectrum.
Color blindness happens when one or more cone types are missing or don't work right. Our simulator mimics this by running your image through mathematical transformations—basically redistributing color information the way a colorblind visual system would.
For example, with deuteranopia (green-blindness), there are no green cones. So we reroute that green wavelength info to the red and blue channels. Result? Reds and greens start looking like the same brownish colors.
The formulas we use come from peer-reviewed vision research (Brettel, Viénot, Mollon, and others). They're accurate enough for professional accessibility testing—which is exactly what we built this for.
Why Designers Use This Tool
Stay WCAG Compliant
Make sure your designs pass accessibility guidelines. Catch issues before they become expensive fixes.
Design for Everyone
Create visuals that work for all users—not just the ones who see color the same way you do.
Catch Problems Early
Find color issues during design, not after launch. Saves time, money, and user frustration.
Step-by-Step Tutorial
Drop Your Image In
Click "Select Image" or drag and drop. We handle JPG, PNG, GIF, WebP, SVG, and BMP up to 10MB.
Pick a Color Blindness Type
Start with deuteranopia (the most common) or test a few different types to see how they compare.
Compare Side by Side
See your original image next to the simulation. Switch between types to spot any problem areas.
Download Your Results
Hit "Download Simulation" to save the image. Great for presentations, documentation, or sharing with your team.
Best Practices for Accessible Color Design
Never rely on color alone. Always pair colors with icons, labels, or patterns. If your traffic light UI uses red/yellow/green, add "Stop"/"Caution"/"Go" text too.
Keep your contrast high. WCAG 2.1 says 4.5:1 for normal text, 3:1 for large text. Use a contrast checker alongside this simulator for full coverage.
Watch out for problem combos. Red-green is tough for deuteranopia and protanopia. Blue-yellow fails for tritanopia. Test anything critical with the simulator first.
Use colorblind-friendly palettes. Tools like ColorBrewer have palettes designed to work across all vision types. Especially useful for charts and data viz.
Test with real users when you can. Simulations are great for catching issues, but nothing beats feedback from people who actually experience color blindness.
Common Use Cases
Web & UI Design
Test buttons, form states, navigation elements, and interactive components for color accessibility.
Data Visualization
Verify that charts, graphs, heat maps, and infographics are readable for all color vision types.
Brand & Marketing
Ensure logos, advertisements, and marketing materials maintain effectiveness across all vision types.
Mobile Apps
Preview app screenshots and UI elements to ensure accessibility before App Store submission.
Educational Content
Test diagrams, illustrations, and teaching materials for students with color vision deficiencies.
Presentations
Verify slide decks and presentation graphics work for diverse audiences.