Check a newly bought screen
Work from the solid colours to the grey ramp and look for bright, dark and coloured pixels.
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Guide
The screen test shows only six local CSS screens: black, white, red, green, blue and a black-to-white grey ramp. Once in the test you can switch with a click, the arrow keys, the space bar or Enter, and leave with Esc; when the Fullscreen API fails it still runs as a full-window overlay.
Updated 2026-09-272 min read
The black screen is the easy place to find a pixel that stays lit, the white and solid colour screens make a pixel that stays dark or shows the wrong colour obvious, and the grey ramp reveals visible banding and burn-in.
Work from the solid colours to the grey ramp and look for bright, dark and coloured pixels.
Use the solid colour screens to look for a fixed patch-shaped outline.
Look again once the screen is clean, so dust is not mistaken for a dead pixel.
Yes — the page falls back to a test layer covering the whole browser window.
Nothing is read from the screen or the system; the test draws local CSS only and uploads nothing.
Updated 2026-09-27
Cycle full-screen solid colors to spot dead pixels, burn-in and banding
Full-screen solid colours cycle through in turn — look carefully at every corner of the screen
Or start from a specific colour:
During the test: click the screen or press →/↓/Space for the next colour, ←/↑ for the previous one, Esc to exit.
Dead pixels (bright/dark spots):On a black screen, a pixel that keeps glowing is a "bright spot"; on a white or solid-colour screen, a pixel that never lights up or shows the wrong colour is a "dark spot" or "colour spot". Their positions are fixed and do not change on any screen.
Burn-in (ghosting):common on OLED screens — a faint outline left by content that stayed in one place for a long time (status bar, navigation keys), most visible on grey or solid colours. Unlike dead pixels, ghosting is a patch of pattern rather than single pixels.
Testing tips:set the brightness above 70%, wipe the screen so dust is not mistaken for a fault, and pause a few seconds on each colour while scanning the corners and the centre; the greyscale gradient also reveals obvious banding (stepped colour).
Manufacturers usually set a threshold for how many faulty pixels are covered by the warranty; take a photo as evidence and contact support.