Dead Pixel Test — Check Your Screen Online

How to run the test properly

Clean the screen first. A speck of dust or a dried splash looks exactly like a stuck pixel against a solid colour, and you will spend ten minutes worrying about a mark that wipes off. Then dim the room, start the test, and look carefully across the whole panel on each colour before advancing. Get close enough that individual pixels are near the edge of what you can resolve.

The colour cycle matters because a faulty pixel only reveals itself against the right background. A pixel stuck on red is invisible on a red field and obvious on green, blue, or black. Running white, black, and each primary in turn is what catches the full range of faults.

Dead, stuck, and hot pixels are different things

A dead pixel receives no power. It stays black on every colour, including a pure white background, where it shows as a small dark dot. Dead pixels are permanent. Nothing you do in software will bring one back, because the transistor driving it has failed.

A stuck pixel is powered but frozen on one colour, usually red, green, or blue. It stays that colour on every background, and is most obvious against black. Because the sub-pixel still works and is merely latched, stuck pixels can sometimes be recovered.

A hot pixel is permanently on and shows as a white dot on a black field. In practice this is the all-sub-pixels-on case of a stuck pixel and behaves the same way.

The distinction is worth getting right before you contact a manufacturer, because it changes both what you can try yourself and what the warranty will cover.

Can you fix a stuck pixel?

Sometimes. The two approaches both aim to jolt the liquid crystal out of its latched state. The first is to cycle the pixel rapidly through colours for anywhere from a few minutes to a few hours, which is what the various flashing-colour videos and utilities do. The second is gentle pressure: switch the display off, press a soft cloth over the exact spot with a fingertip for a few seconds, and switch it back on while releasing.

Be careful with the pressure method. Press hard and you will create new faults, damage the backlight diffuser, or leave a permanent bright patch. On an OLED panel, do not do it at all. Neither method has good odds, and a stuck pixel that has been there for months rarely comes back. A dead pixel will not respond to either.

Will the warranty cover it?

Usually not for a single pixel. Manufacturers work to the ISO 9241-307 standard, which sorts panels into classes and permits a defined number of defective pixels before a display counts as faulty. Most consumer monitors and laptops ship as Class II, which tolerates a handful of dead or stuck sub-pixels across the panel. Policies vary enormously between brands, and a few premium monitor lines advertise a zero-bright-pixel guarantee, so it is worth reading the specific warranty terms rather than assuming.

Test a new screen immediately. Return windows are short, and a retailer will often exchange a panel in the first fortnight when a manufacturer would decline the warranty claim months later. Photograph what you find against a black and a white background before you contact anyone.

When it is not a pixel fault at all

A dark patch that moves when you press the bezel is pressure damage or a loose connection, not a dead pixel. Uneven brightness toward the corners is backlight bleed, common on IPS panels and unrelated to pixels. A faint persistent ghost of a previous image is burn-in or image retention, which affects OLED rather than LCD. And if the whole picture flickers or wavers, look at fixing a flickering laptop screen instead — that is a refresh-rate, driver, or cable problem far more often than a panel one.

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