Dead Pixel Test

What you are looking for

• Dead pixel — always black, on every colour. Easiest to spot on the white screen.
• Stuck pixel — always lit in one colour. Easiest to spot on the black screen.
• Hot pixel — always white. Obvious against black.
• Subpixel fault — only the red, green or blue element has failed, so the dot looks tinted rather than black or white. This is why the test steps through pure red, green and blue separately.
• Clouding or backlight bleed — uneven patches rather than dots, most visible on the black and grey screens.

How to run the test properly

1. Clean the screen first. A speck of dust is indistinguishable from a dead pixel until you wipe it.
2. Go fullscreen so no interface competes for attention.
3. Get close — closer than normal viewing distance — and scan the whole panel, including the corners.
4. Step through every colour. A subpixel fault can be invisible on eight screens and obvious on the ninth.
5. Photograph anything you find, in case you need it for a warranty claim.

Controls

Click or tap anywhere to advance. Arrow keys step back and forward, H hides the overlay for a completely clean screen, and Esc exits.

Found a fault — now what?

For a stuck pixel it is worth trying: rapid colour cycling in that region sometimes frees it, and very gentle pressure through a microfibre cloth while the screen is on occasionally helps. Do not press hard. A dead pixel is permanent, so the question becomes whether your warranty covers it — most set a threshold rather than replacing for a single fault, and a fault near the centre is usually treated more seriously than one at the edge.

While you are checking the panel, the screen colour test covers banding and uniformity, and the refresh rate test confirms it is running at its rated Hz.