Color Vision Plates

Fourteen plates, real methodology, sources cited. A color vision screening built by a colorblind developer, not a marketing funnel. Free, offline, no signup.

I'm colorblind. Every "color blind test" app I tried was either a marketing funnel, an ad farm, or scientifically wrong. So I built the one I wanted: real methodology, sources cited, nothing to sign up for.

Color Vision Plates is a 14-plate screening for red-green and blue-yellow color vision deficiency. It doesn't just say "you're colorblind." It attempts to classify the type: protan (red-weak), deutan (green-weak), or tritan (blue-yellow), using dedicated classifier plates that vanish for one type but not the other.

HOW IT WORKS

• Ishihara-style number plates and HRR-style shape plates (the two standard clinical methodologies, in use since 1917 and 1954) • Classifier plate colors generated by simulating dichromatic vision with the Brettel-Viénot-Mollon (1997) model and selecting pairs that survive one deficiency and disappear under the other • All plate colors defined in CIELAB with matched luminance, so hue is the only available cue: no brightness leaks to give the figure away • A display calibration check before the test starts, because a dimmed or Night-Shifted screen produces false positives • A control plate that catches display problems and flags the result as inconclusive instead of guessing • Plate order shuffles and dot patterns reroll on every retake, so you can't memorize an answer key

WHAT YOU GET

• A plain-English result ("Likely Green-Type Color Difference") with the clinical term alongside for your eye doctor • What the result might mean day-to-day: brake lights, status indicators, charts, ripe fruit • A plate-by-plate review of every answer • Screening history saved on your device, so you can retest over time and compare honestly • The methodology and full citations, one tap away, always

THE HONEST PART

This is a screening, not a medical diagnosis. Phone screens vary; clinical tests use calibrated printed plates under standardized lighting. The app says this everywhere (before the test, on your results, in your history) because a screening tool that oversells itself is worse than none. If your results suggest a color vision difference, see an eye care professional.

PRIVACY

No accounts. No tracking. No analytics. No ads. No network calls. The entire test is bundled with the app and runs offline. Your results stay on your device, and you can erase them anytime.

THE SCIENCE

Ishihara (1917); Hardy, Rand & Rittler (1954); Brettel, Viénot & Mollon (1997); Sharma, Wu & Dalal (2005) for CIEDE2000 color difference; Birch (2012) on prevalence.

From the maker of What Color Is This?, the camera color-identifier built for colorblind people. About 1 in 12 men and 1 in 200 women have a color vision difference. Most found out by accident. This is a better way.

Made by Luke Steuber. Published by Bridge City Lab LLC.