About this tool
The Three Primary Color Deficiencies
Human retinas typically possess three cones (L-cones, M-cones, S-cones) that respectively perceive long, medium, and short light wavelengths (Red, Green, Blue). Color blindness (Dichromacy) occurs when one of these hardware sensors fails:
- Protanopia (1% of males): L-Cones are missing. Red light is utterly absorbed, causing heavy confusion between red, green, and brown. UI "Error" states completely vanish.
- Deuteranopia (5% of males): M-Cones are missing. The most common form of "Red-Green" blindness. Purples look blue, and greens look yellow.
- Tritanopia (Very Rare): S-Cones are missing. Blue appears green, and yellow appears violet or light grey.
The WCAG Principle: "Never Color Alone"
The Web Content Accessibility Guidelines (WCAG) mandate that color can never be the sole indicator of an action. For example, denoting a required form field with merely a red border is a violation. You must include a textual * or an icon alongside the color shift.
How the Simulator Matrix Works
The script converts your base HEX color into linear RGB values, manipulates the color channels utilizing standard Daltonization/LMS transformation matrices, and recompiles the result back into the resulting Hex Code perceived by the deficient human eye.
Practical Usage Examples
Quick Color Blindness Simulator & WCAG Accessibility Tester test
Paste content to see instant image & design results.
Input: Sample content
Output: Instant resultStep-by-Step Instructions
Step 1: Isolate Core UI Variables: Locate the primary brand colors (buttons, warnings, success alerts) in your design system. A standard red #FF0000 error state is often invisible to 8% of the male population.
Step 2: Input HEX Code: Paste the standard six-character HEX code into the interface.
Step 3: Analyze the Dichromacy Shifts: The tool runs the color through a localized RGB array tensor matrix, calculating exactly how the lack of L, M, or S optical cones alters the wavelength perception in the human optic nerve.
Step 4: Audit for Contextual Failure: If you use Red for "Delete" and Green for "Save", and the Deuteranopia simulator outputs the exact same brownish-yellow HEX for both, your UI is fundamentally inaccessible and non-compliant.
Core Benefits
Legal Compliance (ADA & WCAG 2.1): Modern digital accessibility lawsuits explicitly target UIs that rely solely on color to communicate state changes. Validating your palette intercepts massive legal liability.
Captures 8% of Market Share: Approximately 1 in 12 men suffer from Color Vision Deficiency (CVD). If your "Checkout" and "Cancel" buttons look identical to 8% of global consumers, you are systematically hemorrhaging conversion yields.
Replaces Photoshop/Figma Plugins: Developers usually need heavy design suite extensions to simulate Daltonization logic. This instantaneous client-side web tool democratizes accessibility logic for fast rapid prototyping.
Frequently Asked Questions
Functionally in UI design, they trigger similar problems (Red-Green confusion), however biologically they are different. Protanopes completely lack Red cones, which also drastically darkens their perception of red light. Deuteranopes lack Green cones; reds don't necessarily look dark, they just look yellow-brown.
Do not simply try to find a "better red." If you have a red/green conflict, the solution is contrast and geometry. Adjust the Lightness/Luminosity of the colors so one is distinctly lighter than the other, and add icons (like a checkmark vs an X).
Achromatopsia is true, total color blindness (seeing purely in black, white, and gray scales) due to the complete lack of cone function. It is incredibly rare (1 in 30,000), but designing your website to pass a grayscale test guarantees a bulletproof contrast architecture for every user.