Color Blindness Simulator
Upload any image — a screenshot, UI design, chart, or infographic — and instantly see how it appears to people with different types of color blindness. Essential for testing whether your designs are accessible to the 300 million people worldwide with color vision deficiency.
Upload Your Image
Click or drag an image here
Color Blindness Type
Original
Protanopia Simulation
How Color Blindness Simulator Works
Upload an image and see how it looks under protanopia, deuteranopia, tritanopia, and achromatopsia. Test your designs for color accessibility. Configure your settings in the form above and see the results rendered visually in your browser — no server processing required.
Understanding Color Blindness
Color blindness (color vision deficiency) affects approximately 1 in 12 men (8%) and 1 in 200 women (0.5%) worldwide — roughly 300 million people. It is not actual blindness but a reduced ability to distinguish between certain colors. The most common types affect red-green perception, making it difficult to tell reds, greens, oranges, and browns apart. Designers, developers, and content creators must consider color blindness when choosing color schemes for websites, apps, charts, maps, and any visual communication.
Types of Color Blindness Explained
The Four Main Types
- Protanopia: Missing red cone cells. Reds appear dark/black, oranges and greens look similar. Affects ~1% of men.
- Deuteranopia: Missing green cone cells. The most common type. Reds and greens are confused. Affects ~6% of men.
- Tritanopia: Missing blue cone cells. Blues and yellows are confused. Very rare (~0.01% of population).
- Achromatopsia: Total color blindness — only shades of gray. Extremely rare (~0.003%). Often accompanied by light sensitivity.
Design Tips for Color Accessibility
Never use color as the only way to convey information. Always pair colors with text labels, patterns, icons, or shapes. For charts and graphs, use patterns (stripes, dots) in addition to colors. Ensure sufficient contrast between adjacent colors — aim for at least 3:1 contrast ratio between meaningful color pairs. Test your designs with this simulator before shipping. The most critical colors to differentiate: red/green (error/success), orange/gray, blue/purple.
WCAG Requirements for Color
WCAG 2.1 Success Criterion 1.4.1 (Use of Color) requires that color is not the only visual means of conveying information. Success Criterion 1.4.3 requires text contrast of at least 4.5:1 for normal text. Success Criterion 1.4.11 requires non-text contrast of at least 3:1 for UI components. Meeting these criteria ensures your content is accessible to people with color vision deficiencies and low vision.
Frequently Asked Questions
How accurate is this color blindness simulator?
This simulator uses Brettel color transformation matrices with proper sRGB gamma correction. It provides a scientifically accurate approximation of how colors appear to people with each type of color vision deficiency.
What is the most common type of color blindness?
Deuteranopia (green-blind) and deuteranomaly (green-weak) together affect about 6% of men. Red-green color blindness overall affects roughly 8% of men and 0.5% of women.
Is color blindness the same as being blind?
No. Color blindness means difficulty distinguishing certain colors, not an inability to see. Most color blind people see a full range of brightness, just with a reduced color palette.
Can women be color blind?
Yes, but it is much rarer. Color blindness is X-linked recessive, so men (XY) need only one affected X chromosome while women (XX) need two. About 0.5% of women have some form of color vision deficiency.
How should I design for color blind users?
Never rely on color alone to convey information. Use text labels, patterns, icons, or shapes alongside color. Test with this simulator. Ensure at least 3:1 contrast between meaningful color pairs. Avoid red-green as your only distinction.
Is my image uploaded to a server?
No. All processing happens entirely in your browser using the HTML Canvas API. Your image never leaves your device.