Color Blindness Simulator

Upload any image to see how it appears to people with different types of color vision deficiency. All processing happens in your browser — your images are never uploaded.

Red-Green

Blue-Yellow

Complete

Drag & drop your image here or click to select

Supports JPG, PNG, WebP · You can also paste from clipboard

🔒 Your images are processed entirely in your browser. Nothing is uploaded to our servers.

What is a Color Blindness Simulator?

A color blindness simulator is a tool that transforms images to show how they appear to people with different types of color vision deficiency (CVD). It applies scientifically-validated color transformation algorithms to approximate the visual experience of someone with color blindness.

This simulator uses the Brettel, Viénot & Mollon (1997) algorithm — considered the gold standard for color blindness simulation. It accurately models how the absence or malfunction of specific cone cells in the retina affects color perception.

Color blindness affects approximately 8% of males and 0.5% of females worldwide. By using this simulator, designers, developers, and educators can better understand how their visual content appears to people with color vision deficiencies.

How to Take the Test

Upload an Image

Drag and drop, click to select, or paste an image from your clipboard.

Choose a Type

Select from 8 color blindness types grouped by Red-Green, Blue-Yellow, and Complete.

Compare & Download

View the original and simulated images side by side. Download the result as PNG.

Types of Color Blindness Simulated

Red-Green Color Blindness (Protan & Deutan)

The most common form, affecting about 8% of males. Protanopia (no red cones) and Deuteranopia (no green cones) cause difficulty distinguishing reds, greens, browns, and oranges. Protanomaly and Deuteranomaly are milder forms where the cones are present but shifted in sensitivity.

Blue-Yellow Color Blindness (Tritan)

A rare form affecting less than 0.01% of the population. Tritanopia (no blue cones) causes difficulty distinguishing blue from green and yellow from violet. Unlike red-green deficiency, it affects males and females equally and is sometimes acquired through aging or eye disease.

Complete Color Blindness (Monochromacy)

The rarest form where the person sees no color at all (Achromatopsia) or has severely reduced color perception (Achromatomaly). People with complete color blindness see the world in shades of gray and often experience light sensitivity and reduced visual acuity.

Who Needs a Color Blindness Simulator?

Designers & Developers

Ensure your UI, charts, and color palettes remain accessible and distinguishable for users with color vision deficiency.

Educators & Students

Teach or learn about color vision deficiency with real visual examples instead of abstract descriptions.

Family & Friends

Understand how your loved ones with color blindness experience the visual world around them.

Sources

Brettel, Viénot & Mollon (1997) — Computerized simulation of color appearance for dichromats
National Eye Institute (NEI) — Overview of color blindness types, causes, and diagnosis
DaltonLens — Review of open source color blindness simulations
American Academy of Ophthalmology — Clinical information on color vision deficiency

Frequently Asked Questions

No. All image processing happens entirely in your browser using HTML5 Canvas. Your images are never uploaded, stored, or transmitted to any server. This ensures complete privacy.

This simulator uses the Brettel, Viénot & Mollon (1997) algorithm, which is considered the most accurate method for simulating dichromatic vision (Protanopia, Deuteranopia, Tritanopia). For anomalous trichromacy (the milder forms), the simulation approximates the experience by blending the dichromatic result with the original. Keep in mind that individual variations exist — no simulation can perfectly replicate any person's exact visual experience.

Protanopia is a complete absence of red cone cells, making it impossible to perceive red light. Protanomaly is a milder form where red cones are present but have shifted sensitivity, resulting in reduced but not absent red perception. The same relationship exists between Deuteranopia/Deuteranomaly (green) and Tritanopia/Tritanomaly (blue).

The simulator supports JPEG, PNG, and WebP image formats. You can upload images by dragging and dropping, clicking to select a file, or pasting from your clipboard (Ctrl+V / Cmd+V). Large images are automatically scaled down for faster processing.

Yes! This is one of the primary use cases. Upload screenshots of your UI, charts, graphs, or any visual design to see how they appear to people with different types of color blindness. Pay special attention to whether important information is still distinguishable. For formal accessibility testing, also consider checking WCAG color contrast ratios.