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GetWhiteScreen

Dead Pixel Test

Cycles the screen through white, black, red, green, and blue. Each field catches a different fault, which is why running only one of them is the mistake almost everyone makes.

F to start, Space to advance, Esc to exit

Fields: white, black, red, green, blue

How to run it

  1. 1

    Clean the screen first

    Otherwise you will spend ten minutes worrying about a speck of dried coffee. Dry microfibre, no liquid.

  2. 2

    Cycle every field

    Click or press Space. Scan in horizontal bands at about arm’s length rather than taking in the whole panel at once.

Field notes

Each field catches a different fault. That is the entire point.

A dead pixel gets no power and stays black, so white exposes it and black hides it. A stuck pixel is locked on and glows, so black exposes it and white hides it. A single stuck red sub-pixel disappears on the red field and stands out against green and blue.

Run one colour and call the panel clean, and you have tested roughly a third of it. Switch the field below and watch each fault hide itself.

Not a photograph. A grid of pixels drawn at roughly 24× scale, each split into its red, green, and blue sub-pixels, with one dead pixel and one stuck red sub-pixel planted in it. The sub-pixels take their values from the field you pick, so the faults hide and reveal themselves the same way they would on a real panel. Dead pixel: clearly visible as a black dot. Stuck red sub-pixel: invisible, because red is already fully on in white.

Last checked 2026-08-04

Most reported dead pixels are dirt.

The test takes two seconds. Dirt sits on top of the glass, so it smears or moves when you wipe, and it looks the same shade on every field. A dead pixel is inside the panel, lands on an exact pixel boundary, and changes appearance between fields.

If it disappears on reboot, it was never the panel.

A dot that shifts position, only appears at certain resolutions, or clears after a restart or a cable swap is coming from somewhere else. Usually a failing DisplayPort or HDMI cable, a loose connector, or a driver artefact. Swap the cable before you blame the display.

Read the warranty threshold before you start counting.

Manufacturers publish dead-pixel policies specifying how many faulty pixels, and in which zone, qualify for replacement. A defect in the central area usually counts against a stricter threshold than one near an edge.

Knowing your panel’s policy first tells you what you are actually looking for, and whether one pixel is worth a claim at all.

On a phone, one dead pixel is effectively invisible.

At 400 to 500 pixels per inch it is well below what your eye resolves at holding distance. Faults on phones are typically found by pressing your face against the screen during a test like this one, then never being able to find them again. If you cannot see it from where you normally hold the thing, it is not affecting you.

Written by Mor. If a panel of yours behaves differently, tell me and I will correct it.

Questions

Other tools

  • White Screen Test Check a white field for dust, dead pixels, uniformity, and tint.
  • Stuck Pixel Fixer Rapidly flash colors over a stuck pixel to try to un-stick it.
  • Backlight Bleed Test Spot light leaking around the edges of an LCD panel on black.
  • Screen Burn-In Test Reveal retained images and uneven wear on OLED and plasma panels.
  • Monitor Test Full sweep: pixels, bleed, uniformity, and color channels.
  • Light Box Use the screen as a tracing panel or soft photography light.