achromatopsia

Simulate total color blindness (achromatopsia / complete monochromacy) — the world in pure luminance. A color, or a whole image, collapsed to the gray of the same brightness.

npm install achromatopsia

const achromatopsia = require("achromatopsia");
achromatopsia.simulate("#d7191c");            // "#7f7f7f" — the equiluminant gray
const png = achromatopsia.simulateImage("./chart.png");
require("fs").writeFileSync("chart-gray.png", png);

• simulate(color) → the gray hex of the same WCAG relative luminance.
• simulateImage(input, opts?) → a grayscale PNG Buffer (PNG/JPEG in; path, Buffer, or data URI). opts.maxSide caps the longest side (default 2000).

Luminance is opticquiz-cvd's relLuminance, re-encoded to sRGB gray. This is the total-monochromacy end; for the dichromacies see dichromacy. A simulation, not a diagnosis.

Licence

MIT.