Dead Pixel Test

Clean the screen, turn the brightness up, and open this page in the device's own browser. Press Start fullscreen test and look at each colour from about arm's length, then up close, sweeping across the screen in sections rather than staring at the middle. A dead pixel stays dark on every lit colour and shows best on white; a stuck or hot pixel shows as a bright or coloured dot on black. For a TV, open the page in the TV's built-in browser where you can. Casting or mirroring a laptop tab also works, but the compression it adds can soften a single pixel.

Every pixel is made of red, green, and blue subpixels. A dead pixel never lights: it stays black on every colour and is easiest to see on white. A stuck pixel has one or two subpixels held on, so it shows as a red, green, blue, or mixed dot, most obviously on black. A hot pixel is a stuck pixel with all three subpixels on, so it glows white on black. A dead or stuck subpixel is the partial case, where one element misbehaves while the other two work, which is why the test includes each primary colour on its own.

A dead pixel, no. The transistor that switches it has failed, and no software can change that. A stuck pixel sometimes recovers by itself with normal use, and stuck pixel fixers try to hurry that along by flashing rapidly changing colours over the spot for minutes at a time. They occasionally help a stuck pixel and never revive a dead one. This page deliberately does not flash: rapidly alternating full-screen colours can trigger seizures in people with photosensitive epilepsy, and the web accessibility guidelines (WCAG 2.3.1) cap content at three flashes a second for that reason. If you try a fixer anyway, keep it to a small window, look away while it runs, and skip it entirely if you or anyone nearby is sensitive to flashing light. Avoid the pressure method of pressing or rubbing the spot: it can damage the panel's layers and neighbouring pixels, and it may void the warranty.

It depends on the manufacturer and the product line, and policies change, so read the one for your exact model. Most count bright dots (hot and stuck pixels) separately from dark ones, often tolerate fewer bright ones, and some care whether a fault sits near the centre of the screen. The ISO 9241-307 standard defines pixel fault classes that set how many faults of each type a panel may have, and many policies follow similar thresholds. The shop's return window is often the easiest route for a new screen, so test as soon as it arrives.

Yes, with caveats. On OLED, each pixel makes its own light and black is truly off, so a hot or stuck pixel stands out sharply and backlight bleed cannot happen, though very dark greys can show faint uneven patches instead. On phones, browsers limit fullscreen, and iPhone Safari does not offer it to web pages at all, so the test fills the page and the browser's bars may stay; turn the phone to landscape and hide the toolbar if your browser can. For a TV, use its web browser or cast a tab, and choose a standard picture mode so sharpening and noise reduction do not smooth a single pixel away.

They are the two extremes. On black, every pixel should be off, so anything lit (a hot pixel, a stuck pixel, or light leaking around an LCD's edges) stands out. On white, every subpixel should be fully on, so a dead pixel shows as a crisp dark dot. The primary colours then narrow a fault down to the one subpixel that has failed, and the 50% grey field shows uneven patches that both extremes can hide.

Dead and stuck pixels are tiny, sharp points that sit in exactly the same place every time. Backlight bleed and IPS glow are larger, soft areas of light, usually at the edges or corners of a black screen. Move your head to tell those two apart: bleed stays put, while glow shifts or fades with the viewing angle. Both look their worst on a black screen in a dark room, so check them again with real dark content at your normal brightness before deciding they matter.

Yes. Night Light on Windows, Night Shift and True Tone on Apple devices, blue light filters, eye comfort modes on Android, accessibility colour filters, and HDR tone mapping all shift what the screen shows, which can make white look yellow or grey look uneven. They cannot create or hide a dead pixel, but they can make a faint stuck subpixel harder to judge, so turn them off for the test. Browser zoom and display scaling do not matter, because a solid colour looks the same at any size.

Ten to twenty seconds per colour is enough for a careful pass, sweeping your eyes across the screen in sections. Spend longer on black and white, which find most faults. If you would rather not click, auto-cycle moves on every 1 to 10 seconds, and three seconds is a sensible pace for a second look. Because a stuck pixel can come and go, a new screen is worth a second pass after it has been on for half an hour.

A dead or stuck pixel does not infect its neighbours, and most stay isolated for the life of the screen. New faults can still appear over time, though, and a growing cluster usually points to physical damage, pressure, or a failing panel rather than one pixel spreading. If you notice several new faults or a line across the screen, photograph them and contact the seller or manufacturer while you are still covered.