Color Blindness Simulator

The simulator reads the pixel data of your uploaded image and applies a mathematically derived color transformation matrix to each pixel, based on models published by researchers Brettel, Viénot, and Mollon. This approximates how the same image would appear to someone with the selected color vision deficiency. All processing happens entirely in your browser — your image is never uploaded to a server.

Color blindness affects approximately 8% of males and 0.5% of females of Northern European descent. The most common form is red-green color blindness (deuteranomaly and deuteranopia), affecting around 6% of males. This means roughly 1 in 12 men and 1 in 200 women have some form of color vision deficiency. Globally, that's over 300 million people.

If your design relies solely on color to convey information — for example, red = error, green = success — a significant portion of your users will not perceive that distinction. Good accessible design uses color plus shape, text, or pattern to communicate status. WCAG guidelines also require sufficient color contrast between text and backgrounds. The color blindness simulator and the Color Contrast Checker together help you identify and fix these issues.

No. All processing is done entirely in your browser using the HTML5 Canvas API. Your image never leaves your device and is never transmitted to any server. This is consistent with FocusFlow's privacy-first approach — no data is collected, no analytics are used within this tool.

Deuteranopia is a form of dichromacy — the person has no functioning green cone cells. They see only two primary colors instead of three. Deuteranomaly is a form of anomalous trichromacy — the green cone is present but shifted in sensitivity, leading to a milder color perception shift. Deuteranomaly is the most common form of color vision deficiency overall, affecting roughly 5% of males.