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White Screen
Fills your entire screen with solid white. Cleaning the screen, spotting dust and dark…
Yellow Screen
Fills your entire screen with solid yellow. Testing red and green together — the brightest combination, useful for spotting dimming toward the edges.
Screen Tests
Nothing uploaded
No sign-up
Free, unlimited
Press Fullscreen, then look closely at the whole panel.
In short
A yellow screen lights red and green together with blue off, and because red and green carry most of what the eye reads as brightness, it is the brightest field of the twelve. That makes it the best one for spotting edge dimming — panels that fall off in brightness toward the corners, which is common on edge-lit displays and on laptop screens. Against a maximally bright field the drop-off is easier to see than against any darker colour. It is also the complement of blue, so a pixel stuck on in blue appears as a distinct cool dot in a field containing no blue at all. The brightness cuts both ways: a full yellow field at high brightness is genuinely uncomfortable to look at for long, so keep the session short and drop the brightness if you need more time. If you are checking for dust and marks rather than uniformity, white is the more comfortable choice and shows the same things.
How to use the Yellow Screen
- The test starts on its own — no button to press and nothing to install.
- Follow the prompt in the test panel and watch the readings update live.
- Press Reset to start over with a clean slate.
About the Yellow Screen
The Yellow Screen fills your entire screen with solid yellow. Testing red and green together — the brightest combination, useful for spotting dimming toward the edges. It runs as plain JavaScript inside the page, which means there is no upload step, no queue and no size limit imposed by a server — the only limit is your own device.
What people use it for
- Testing red and green together — the brightest combination, useful for spotting dimming toward the edges.
- Checking a monitor or phone screen before a return window closes.
- Using as a plain backdrop for photography or for cleaning the screen.
Press Fullscreen above before judging anything. A colour patch surrounded by page furniture tells you very little — the panel needs to be filling the whole screen, ideally in a dark room, with any night-light or blue-light filter switched off.
Frequently asked questions
What is the difference between a dead and a stuck pixel?
A dead pixel receives no power and stays black on every colour. A stuck pixel is latched on and shows the same bright red, green or blue dot against every background. Stuck pixels sometimes recover; dead ones never do.
How do I tell a dead pixel from dust?
Dust sits on the outside of the glass and moves or disappears when you wipe the screen with a microfibre cloth. A dead pixel does not move and stays in exactly the same position on every colour.
How many dead pixels before I can return a monitor?
That depends on the manufacturer's policy, which is usually written against the ISO 9241-307 pixel fault classes. Most consumer panels are sold to a standard that tolerates several sub-pixel faults, so check the specific warranty terms — and photograph what you find while the panel is still within the return window.
Is the Yellow Screen free, or is there a paid tier?
Free, unlimited, and no email address required. You can use it a hundred times a day and nothing changes.
Is the Yellow Screen safe to use with private information?
No. The Yellow Screen runs entirely in your browser using JavaScript. Nothing is transmitted, logged or stored, which you can verify yourself in the Network tab of your browser's developer tools.
What problem does the Yellow Screen solve?
The jobs it is built for: testing red and green together — the brightest combination, useful for spotting dimming toward the edges. Checking a monitor or phone screen before a return window closes. Using as a plain backdrop for photography or for cleaning the screen. It is built for exactly those cases rather than being a general-purpose tool with this bolted on.
What do people usually get wrong here?
Press Fullscreen above before judging anything. A colour patch surrounded by page furniture tells you very little — the panel needs to be filling the whole screen, ideally in a dark room, with any night-light or blue-light filter switched off.
Do I need to install anything to run this test?
No installation, no extension and no driver. The Yellow Screen uses the browser's own device APIs and begins as soon as the page loads, so there is nothing to press first. Press Reset at any point to start over with a clean slate.
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