Dead Pixel Test — Guided Full-Color Check

Plate III — six-color sweepready

Tap to begin the sweep

advance every 6 s

Wipe the screen first — dust impersonates dead pixels with total commitment.

During the sweep: tap / → next color · ← back · Esc end

How to read each screen

On white — a dark dot that stays put is a dead pixel (its transistor gave up). A colored dot is a stuck subpixel: only red, green or blue firing.
On black — the reverse test. Any pinprick of light is a stuck subpixel. Faint glow near the edges isn't pixels at all; that's backlight bleed, which has its own check.
On red, green, blue — these isolate the three subpixels. A dark dot on the red screen but not the others means precisely the red subpixel of that spot is out.
On grey — the panel's least flattering color. Uneven patches, vertical banding and dirty-screen effect all show here before anywhere else.

Before you claim the warranty

Manufacturers publish pixel-defect policies, and most allow a few dead subpixels before a panel counts as faulty — ISO 9241-307 Class II, the common tier, tolerates up to two dead pixels per million. One defect dead-center hurts more than three in a corner, but the policy counts, not your feelings. Photograph what you find (phone camera, close, screen at half brightness so it doesn't blow out) and check the maker's policy page before boxing anything up. And genuinely wipe the screen first; support forums are full of dust returns.

Stuck isn't always dead

A stuck subpixel — one glowing color — sometimes unsticks. Rapidly cycling colors over the spot for a few minutes gives it a workout; it's the one folk remedy with a plausible mechanism, since it forces the transistor through its range. No promises: a truly dead (dark) pixel has no circuit left to exercise, and nothing software does will raise it. We'd rather tell you that than sell you a miracle.