Guide
How to Check a New Monitor Before the Return Window Closes
Dead pixels, backlight bleed and IPS glow are three different things with three different verdicts. Here is…
White Screen
Fills your entire screen with solid white. Cleaning the screen, spotting dust and dark blemishes, and checking backlight uniformity across the panel.
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Press Fullscreen, then look closely at the whole panel.
In short
A full white screen is the field that shows you anything DARKER than the panel should be, which makes it the one for dust, smears and dead pixels. A dead pixel receives no power and stays black on every colour, so against white it is an unmistakable dark dot. The most useful thing white does, though, is settle the dust question: dust sits on the outside of the glass and moves or vanishes when you wipe with a dry microfibre cloth, while a dead pixel does not move and stays exactly where it was. Wipe first, then look again — that single step accounts for most of the pixel faults people think they have found. White also shows backlight uniformity as gross unevenness, though mid grey shows that far better, because a bright field masks small differences. What white will NOT show is a stuck pixel latched on in red, green or blue, since a bright dot on a bright background is nearly invisible. For that, use black. Judge all of it fullscreen, at native resolution, with any blue-light filter switched off.
How to use the White 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 White Screen
The White Screen fills your entire screen with solid white. Cleaning the screen, spotting dust and dark blemishes, and checking backlight uniformity across the panel. 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
- Cleaning the screen, spotting dust and dark blemishes, and checking backlight uniformity across the panel.
- 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.
Explained in our guides
All guidesFrequently 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 White Screen free, or is there a paid tier?
It is free, with no account, no trial and no daily cap. Every screen tests tool on inputtesthub.com works the same way: open the page and use it.
Is what I paste into the White Screen stored?
No. The White Screen runs entirely in your browser using JavaScript. Your input never reaches inputtesthub.com or any third party — open your browser's Network tab while you use it and you will see no request go out.
What is the White Screen used for?
The most common reasons people reach for it: cleaning the screen, spotting dust and dark blemishes, and checking backlight uniformity across the panel. 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.
Any caveats I should know about?
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.
Why does the test start on its own?
No installation, no extension and no driver. The White 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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