About Color Blindness Test

Color Blindness Test is an independent, free collection of browser-based color-vision tools: thirteen screening and simulation pages in seven languages, built on open-source plate designs and published color science. This page explains who is behind it, how it works, and the principles that shape every word on the site.

What this site is

A focused toolbox, not a portal. Each of the thirteen tools answers one real search intent — a complete 14-plate color blind test, a classic Ishihara digit test, axis-specific red-green, deutan, blue-yellow and tritan screens, a shape-based test for children, a reverse-plate experiment, and a fully local image simulator. Every tool runs entirely in your browser: no account, no upload, no result storage. Close the tab and everything is gone.

Who runs it

The site is maintained by the Color Blindness Test editorial team — a small group of developers and writers with experience in web engineering, accessibility and science communication. We are not a clinic and employ no physicians; where medical facts appear (prevalence, testing practice), they come from cited public sources such as the U.S. National Eye Institute, and the byline on every tool page points to this organization rather than to invented experts.

Why it is free — and stays free

There is no business model attached to the tests:

• No accounts. Nothing to sell you later.
• No result storage. There is no database of answers because answers never leave your tab.
• No behavioral analytics. We do not run user-tracking scripts; the tools' pages make no third-party requests while you test.
• No paid placement. There is nothing to upsell.

Running costs are a static web host and a domain. That is deliberate: a screening experience works only if the incentive structure has nothing to gain from your result.

How the content is maintained

Every tool page is long-form documentation, not filler: what the tool measures, how to prepare the display, honest limits, and a FAQ grounded in real questions. Each page carries a visible last-updated date that also appears in its machine-readable metadata, so both readers and search engines can judge freshness. When plate definitions or scientific references change, we update the pages and bump the dates rather than silently editing.

Sourcing rules

1. Facts about vision and testing are cited to public institutions or peer-reviewed work — currently the National Eye Institute, a 2024 display-comparison study, and the 2009 Machado simulation paper.
2. Plate data is open source with preserved licenses and checksums (see methodology and licenses).
3. We do not copy the copyrighted Ishihara booklets or any other commercial plate set. All artwork is generated from the open definitions described on the methodology page.

The honesty principle

The most important design rule on this site: the tools never claim to diagnose. The plates are experimental; screens shift colors; two directed plates cannot type anyone. So every result is phrased as what you recognized, every page carries the non-clinical disclaimer, and every "what now?" pointer leads to a professional exam rather than to a product. We would rather under-claim and be trusted than over-claim and mislead — especially on pages about children's vision.

Languages

The site publishes in English, French, German, Spanish, Japanese, Korean and Italian. Each language is written as native content — locally searched keywords, local contexts for driving, school screening and occupational exams — rather than machine-translated filler, because a screening page someone cannot comfortably read is a screening page that cannot help them.

Contact and corrections

Found a factual error, a broken localization, or an accessibility barrier? The contact page explains how to reach us and what we need to fix things fast. Corrections are published with updated dates — silent edits are not our style.

At a glance

• Tools: 13 pages (12 screening experiences + 1 local simulator)
• Languages: 7 (English default)
• Plate sources: color-vision-plates (MIT), ishihara PyPI package (MIT), dichroma (MIT)
• Data collected by tests: none
• Clinical claims made: none, on purpose