Color Blind Test

Color Blind Test is a private color blindness test built on the Ishihara plates — the pattern of coloured dots used to check red-green colour vision for over a century. Look at a plate, tap the number you see, and the app tells you what your readings are consistent with. Nothing is guessed for you, and no part of the result is behind a payment. WHAT YOU GET • Three lengths: the full 38-plate Ishihara sequence, a 21-plate screening run, or a 6-plate quick colour vision check. • Tap to answer. Every plate offers the readings it can produce, plus "I don't see anything" and "I see something but can't read it" — both full size, on every plate. Saying you cannot read a plate is an answer, not a failure. • A result you can check for yourself. The app shows the arithmetic: how many plates you read as someone with typical color vision would, against the two thresholds the protocol uses. • Protan and deutan indication. Plates 22 to 27 are the ones that separate the two red-green axes, and the app reports which way your readings lean. • A plate-by-plate review — every plate you saw, the answer you gave, what a typical observer reads, what a red-green color blind observer reads, your response time, and a plain-language note on what that plate is testing. • A PDF color vision report to keep or hand to an optometrist, with each plate printed large, one to a page, beside your own answers. • 15 languages, light and dark themes, an optional 3-second timer, and no account of any kind. HOW IT IS BUILT • Every plate is generated on your device. The dots are laid out fresh each run, so the arrangement is never the same twice and cannot be memorised — while the figure inside them never changes. • The dots are luminance matched. Brightness carries no information about the number, so squinting, screenshotting or dimming the screen cannot reveal an answer that colour alone should carry. • Nothing beside a plate is coloured. Saturated colour next to a plate changes how the dots look, so that screen is grey by design. • No result uses a red-and-green color pair to mean anything. In an app about red-green color blindness that would be unreadable by the very people it is for. PRIVACY Your readings stay on your device and are never written to disk — no history, no account, no sign-in, no server. Close the app and the run is gone. The PDF exists only as the file you choose to save or share. The app is free and supported by ads, which use an advertising ID. You can review that choice at any time in Settings. One optional video unlocks the PDF file for a result; the result itself, the protan and deutan classification and the plate-by-plate review are always free. PLEASE READ This app is not a medical device. It does not diagnose or treat any condition and is for information only. Phone screens vary enormously. Screen technology, brightness, colour profile, night-shift and blue-light filters and the light in the room all change how the plates appear, and two runs on two devices can differ. A result of "borderline" means your readings fell between the two thresholds and this method cannot settle it — that is a real outcome, not a fault. For anything that matters — a medical opinion, a job, a licence, aviation or driving — see a qualified optometrist or ophthalmologist. The plates are generated from the published Ishihara answer key. They are not reproductions of the printed Kanehara plates, and this app is not affiliated with or endorsed by Kanehara Trading Inc.