Dead pixel test
Nine solid colours, full screen. Faults have nowhere to hide.
This fills your screen with solid colours one at a time. Clean the screen first — dust looks just like a stuck pixel.
- • Dead pixels stay black — look for them on the white screen.
- • Stuck pixels stay lit — look for them on the black screen.
- • Check the corners and edges last; that is where faults gather.
How to check for dead pixels
A dead pixel never lights up, so it shows as a black dot and is easiest to spot on white. A stuck pixel is the opposite — permanently lit in one colour, obvious against black. Because the two hide on opposite backgrounds, a single test colour cannot find both, which is why this cycles through nine. Run it in full screen: the edges of a panel are where faults cluster, and a colour swatch inside a web page cannot show you the edges. Worth doing on a new monitor, laptop or phone while you can still return it.
- 1Clean the screen first — dust and smudges look exactly like stuck pixels.
- 2Press the button to fill the whole screen and dim the room a little.
- 3Click or press any key to move to the next colour; work through all nine.
- 4Look closely at the corners and edges, then press Escape to exit.
FAQ
What is the difference between a dead and a stuck pixel?
A dead pixel receives no power and stays black on every colour. A stuck pixel is fixed at one colour and stays visible against black. Stuck pixels sometimes recover; dead ones do not.
Can a stuck pixel be fixed?
Occasionally. Rapidly cycling colours over the area for twenty minutes or so can unstick it, and very gentle pressure with a soft cloth while the screen is on sometimes works. Neither is guaranteed, and pressing hard can make things worse.
How many faulty pixels before a warranty claim?
It varies by manufacturer and panel class — many require several before replacing a monitor, though a single fault near the centre is often treated more seriously than one at the edge. Check your specific warranty terms.
I see a dark patch, not a dot.
That is more likely backlight bleed or clouding, which is a different fault. It shows as an uneven glow on the black screen rather than a single sharp point.