White Screen Test
Fill the entire display with white light to inspect dust, scratches, stuck pixels, and uneven backlighting.
Test interface
Your browser may ask for permission after you press Start.How to use this tool
- Click Start white screen to open a full-screen white field.
- Raise or lower the brightness slider to match your inspection needs.
- Look for dark spots, coloured dots, streaks, or uneven brightness across the panel.
- Press Escape, tap the screen, or click Exit to return to the controls.
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Technical explanation
The test uses a full-viewport white element and the Fullscreen API. A pure white field exposes dust, smudges, scratches, and stuck pixels that can be hard to see on normal content.
It also reveals backlight uniformity problems such as bright corners or dark patches. Perceived brightness depends on the display profile, ambient light, and the device brightness setting, so this is a visual inspection aid, not a calibration measurement.
Troubleshooting
The screen is not pure white
Disable night light, blue-light filters, and colour inversion. Check that the browser zoom and any overlay extensions are off.
Full screen shows browser bars
Some browsers keep a small exit hint visible. That is normal and is controlled by the browser.
Brightness slider does nothing
The slider adjusts the rendered white level, not the hardware backlight. Use the device brightness keys for hardware brightness.
I see faint grey lines
Uniformity and panel technology can produce faint banding. Compare with another device before treating it as a fault.
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Frequently asked questions
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