CORRECT COLORS
ON EVERY SITE
A browser extension that re-colors any web page in real time so you can tell colors apart — maps, charts, dashboards, red warning text. Pick your type of color blindness once and it follows you across the whole web.
All three listings are live. No account, nothing to configure. On a phone or tablet? Your device has a built-in color filter — browsers there mostly don't take extensions. Developers can also load it unpacked from GitHub.
HOW IT WORKS
Click the toolbar eye and choose a mode. The page's colors are re-mapped so the differences your vision normally compresses become visible again (daltonization, via an in-browser color filter). Your choice is remembered as you browse.
It corrects, it doesn't simulate — the point is to help you see, not to show sighted people what color blindness looks like. It runs on the same published method as the rest of OpticQuiz: Machado (2009) simulation, scored with CIEDE2000.
PRIVATE BY DESIGN
No tracking. No network requests. No account. Everything happens in your browser; your chosen mode is stored only on your device. See the full privacy policy.
YOUR DEVICE HAS ONE BUILT IN
An extension can only correct web pages. Every major operating system ships a color filter that corrects everything — your desktop, your photo library, games, video, other people's apps. If you need correction beyond the browser, start here. It costs nothing and installs nothing.
On a phone or tablet this is usually your only option — Chrome on Android supports no extensions and iOS has no equivalent. Firefox for Android is the exception that does take add-ons.
How good are they? Nobody outside the vendors can say, and we tried. None of Microsoft, Apple or Google publishes the transform their filter applies. We attempted to measure the Windows one so it could be compared against a published method, and found it is invisible to three independent capture paths — ordinary screenshots, the desktop-duplication API that screen-sharing uses, and the public color-effect API all return the unfiltered image while the screen is visibly changed. We could not recover the transform, so we make no claim about how well it works — only that it cannot currently be checked by anyone outside Microsoft. That measurement is written up here, and the method and data are in the repository.
Practical consequence you can use today: because the filter sits below the screen-capture layer, a screenshot you take with a system filter on will not show what you saw. If you are reporting a color problem to a developer, say which filter you had on — the image won't carry it.
position:fixed or sticky can shift, and because the transform moves lightness as well as hue a page's text contrast can change; switch to Off to restore. The site widget was rebuilt to remove all three, and that engine is being ported here next. Method: published, open-access.