How to Check a Screen for Dead Pixels

Run the test

1. Wipe the screen with a dry microfiber cloth, so dust does not look like a fault.
2. Open Dead Pixel Test and click Start full screen.
3. Look across the whole screen on each color, from about 30 cm away. Click or press Space for the next color, and Esc to finish.

What you might see

• Dead pixel: a black dot that stays black on every color. Easiest to see on white.
• Stuck pixel: a dot that stays red, green or blue. It shows on black and on the other colors.
• Hot pixel: a white dot that stays lit, visible on black.
• Backlight bleed: light leaking in at the edges or corners on a black screen, easiest to see in a dark room.

What to do about it

Test a new screen as soon as it arrives, while you can still return it. Manufacturers have their own policies, often allowing a small number of faulty pixels before they replace a panel, so check the warranty terms and keep a photo of the fault.

Stuck pixels sometimes free themselves after a few days of use. Dead pixels, which get no power at all, almost never come back.

Check the resolution too

When buying second-hand, check the screen resolution as well, to make sure the panel is the one advertised.