Colorblind Simulator
A free color blindness simulator for previewing how designs, photos, and artwork appear to people with color vision deficiency. Supports protanopia, deuteranopia, tritanopia, and achromatopsia.
Upload images and see how they look through the eyes of colorblind people
Features
How to Simulate Color Blindness on Images
Drag and drop a PNG, JPG, WebP, or BMP file into the upload zone, or click to browse. You can also paste from clipboard.
Choose from 7 types: protanopia, deuteranopia, tritanopia, achromatopsia, plus anomalous variants (protanomaly, deuteranomaly, tritanomaly).
Use the severity slider to simulate partial color vision loss. Most CVD is mild, not the extreme form.
Drag the divider left and right to compare the original and simulated images side by side in real time.
Click "Download Result" to save the simulated image as PNG for presentations, reports, or accessibility audits.
Frequently Asked Questions
What is color vision deficiency (CVD)?
Color vision deficiency, commonly called color blindness, is a condition where certain cone cells in the retina do not function normally. This makes it harder to distinguish between specific colors. About 8% of men and 0.5% of women have some form of CVD.
What is the difference between protanopia and deuteranopia?
Protanopia means the red cone cells are absent (red-blind), while deuteranopia means the green cone cells are absent (green-blind). Both are red-green color blindness, but protanopia also causes red colors to appear darker. Deuteranopia is the most common type.
What does the severity slider do?
Most people with color vision deficiency have anomalous trichromacy — their cone cells work, but with shifted sensitivity. The severity slider lets you simulate the full spectrum from mild anomaly (e.g., deuteranomaly) to complete dichromacy (e.g., deuteranopia).
What is Daltonize?
Daltonize is a technique that takes the color information lost in a particular type of color blindness and shifts it into color channels that the person can still see. It helps colorblind viewers distinguish colors they would otherwise confuse.
Why should designers use a colorblind simulator?
About 1 in 12 men has some form of color vision deficiency. If your website, app, or infographic relies on color alone to convey information, a significant portion of your audience may miss important details. Testing with a simulator helps you create more accessible designs.
Is my image uploaded to a server?
No. All processing happens entirely in your browser using Canvas API and mathematical color transformation. Your images never leave your device.
How accurate is this simulation?
The simulation uses scientifically derived color transformation matrices based on the Brettel, Vienot, and Machado models. While no simulation can perfectly replicate another person's visual experience, these models are widely accepted in accessibility research.
We can — and it's free! Just send us a quick message with your idea. If you'd like to discuss it in detail, leave your email and we'll get back to you. You can stay anonymous.
