How do I test my website for color blindness?
Approximately 1 in 12 men and 1 in 200 women experience some form of Color Vision Deficiency (CVD). If your website UI, product design, or data charts rely strictly on red and green colors to convey information (such as error states or pie charts), a massive portion of your audience cannot understand them. Our Color Blindness Vision Simulator allows designers to instantly test their mockups.
By applying clinically accurate mathematical matrices to your uploaded images, you can instantly see exactly how your graphics appear to users with Protanopia, Deuteranopia, or Tritanopia.
👁️ Color Blindness Vision Simulator
Ensure your UI designs, charts, and graphics are accessible to everyone. Upload an image to simulate how it appears to users with Protanopia, Deuteranopia, or Tritanopia.
How to Use the Simulator
Testing your designs for WCAG accessibility compliance is incredibly fast and completely secure:
- Upload a Design: Drag and drop an image of your UI mockup, logo, or data visualization chart into the workspace.
- Toggle the Vision Filters: Click through the vision deficiency buttons on the right sidebar. The HTML5 Canvas engine instantly recalculates every pixel on your image.
- Check Contrast: Specifically, look for places where you relied on color to tell a story. Does your red “Delete” button blend in completely with your green “Save” button under the Deuteranopia filter? If so, you need to add an icon or a text label!
- Download the Proof: Click the export button to download the simulated image. This is a great way to show stakeholders or clients exactly why you are recommending specific accessible color palettes for a project.
Understanding the Types of Color Blindness
Our engine uses four mathematical matrices to simulate the exact physiological responses of the human eye’s cones.
1. Deuteranopia (Green-Blind)
This is the most common form of color blindness. People with Deuteranopia lack functional green cones in their eyes. Because green and red color channels heavily overlap in human vision, this condition makes reds, greens, oranges, and browns look incredibly similar to one another.
2. Protanopia (Red-Blind)
Similar to Deuteranopia, Protanopia makes reds and greens difficult to distinguish. However, because they lack functional red cones, pure red colors appear much darker (almost black or dark grey), while greens appear faded.
3. Tritanopia (Blue-Blind)
A much rarer condition where the blue-sensing cones are missing. Under this simulation, you will notice that blues appear as a muddy green, and yellows appear as a violet or light pink.
4. Achromatopsia (Grayscale)
Also known as total color blindness. Individuals with this extremely rare condition see the world entirely in shades of grey, black, and white. Testing your design in Grayscale is the ultimate test of “Value Contrast.” If two buttons look identical in grayscale, they do not have enough contrast, regardless of their color!
Why Use a Client-Side Simulator?
If you are a UX/UI designer working on an unreleased app or a highly confidential corporate dashboard, uploading your Figma screenshots to a random “free accessibility checker” online is a massive security risk.
We built this simulator using native browser JavaScript. When you drop your image into the tool, the matrix calculations happen entirely within your computer’s RAM. Your designs are never uploaded, stored, or transmitted to an external server, ensuring absolute privacy for your intellectual property.
Frequently Asked Questions (FAQ)
Q: Does this tool work on live websites?
A: No, this tool requires an image file (PNG, JPG). To test a live website, you should take a screenshot of the page or export your artboard from Figma/Sketch and upload the image file here.
Q: How accurate is this simulation?
A: Highly accurate. The engine uses the standard transformation matrices developed by color scientists (often referred to as the Machado or Viénot models). These are the same mathematical formulas used by advanced software like Photoshop and modern operating systems to simulate CVD.
Q: What is the best way to fix a design that fails the test?
A: The golden rule of accessibility is never to use color alone to convey meaning. If you have a line chart where the “Good” line is green and the “Bad” line is red, change the lines so one is dashed and one is dotted. If you have an error state, make sure an “X” icon or text warning appears alongside the red color shift.