How to test for dead pixels
- Clean the screen gently with a dry microfibre cloth so dust is not mistaken for a pixel fault.
- Press Start full-screen test. The whole screen fills with one colour; tap, click or press the right arrow to step through red, green, blue, white, black and more.
- Look closely at every area of the screen on each colour, ideally in a dim room. A dot that stays black on bright colours is a dead pixel; one that stays a single colour is a stuck pixel.
Dead, stuck and hot pixels
Each pixel on an LCD or OLED screen is made of red, green and blue sub-pixels. A dead pixel never lights up and shows as a black dot, most visible on white. A stuck pixel has one or more sub-pixels permanently on, so it shows as a red, green, blue or other coloured dot, most visible on black. A "hot" pixel is always white. Pure single-colour backgrounds make each kind easy to spot, which is why testing every colour matters.
Stuck pixels can sometimes be revived by rapidly cycling colours over them, which the flashing fixer does; it works for some stuck pixels but cannot repair dead ones. Gentle pressure with a soft cloth while the screen is on is another old trick, but avoid pressing hard. Check a new monitor, laptop or phone as soon as you buy it: retailers and manufacturers have "pixel policies" that allow returns above a certain number of faulty pixels, typically within a short window.
How do I know if I have a dead pixel?
Run the full-screen test. A black dot on white or coloured screens is dead; a coloured dot on black is stuck.
Can a dead pixel fix itself?
Truly dead pixels rarely recover. Stuck pixels sometimes do, especially with the flashing fixer.
Is a dead pixel covered by warranty?
It depends on the manufacturer's pixel policy; many replace a screen only above a minimum number of faulty pixels.