Your files stay on your device

# Dead pixel test

Fill the screen with solid colors to spot dead or stuck pixels.
viewport cycle. White shown nowFullscreenAuto-cycleWhite. #ffffffSolid colorsGray rampBanding barsCheckerboardMoving bar

Dead (always black) and stuck (always one color) pixels stand out against a solid fill.
WhiteBlackRedGreenBlue

Dead (black) pixels: dark specks that never light. The classic first check.

- This test cannot see your screen; it shows known colors full-viewport and your eyes are the detector. No camera, no analysis, no claims about what it found.
- Fullscreen covers the whole panel including browser chrome; without it, the cycle still fills the viewport, which catches most of the screen but not all. Esc exits fullscreen at any time (the browser guarantees it); Space and the on-screen buttons step colors.
- Work through the five colors slowly. A dot that stays dark on white is a dead pixel; a dot that keeps its own color on black is stuck. One sub-pixel channel failing shows only on its color and black; that is why there are three primaries, not one.
- Dust on the panel mimics a dead pixel; clean the screen first. Very small dead pixels can hide at low brightness; the test says nothing about warranty terms, which manufacturers set by count and location.
Paste, drop, or type to begin. Everything stays on this device.

## More device tests

- [Refresh rate test](/device/refresh-rate)
- [Screen & viewport](/browser/screen)
[All device tests](/device)

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Canonical HTML: https://nutter.tools/device/dead-pixel/
Markdown version: https://nutter.tools/device/dead-pixel/index.md
Plain-text version: https://nutter.tools/device/dead-pixel/index.txt
Agent index: https://nutter.tools/llms.txt