Dead pixel or stuck pixel? Test a new screen before the return window closes

A screen defect is easy to get replaced in the first few days, much less so afterwards. Take five minutes as soon as you unbox a monitor, laptop or TV.

Before testing

• Clean the screen with a dry microfibre cloth: a speck of dust looks like a dead pixel.
• Test in a fairly dark room.

Running the test

Open the dead pixel test and go full screen. Cycle through the colours and look at each area of the screen, straight on, about 50 cm (20 inches) away.

Reading the result

• A dot stays black on every colour: that's a dead pixel. It can't be repaired.
• A dot stays red, green or blue: that's a stuck pixel. It sometimes unsticks when you display rapidly changing colours for a few minutes.
• A light halo in the corners on a black background: that's backlight bleed, common on LCD screens. It only matters if you can see it in normal use.

Making a warranty claim

Each manufacturer publishes a pixel policy setting the number and type of defects it accepts. Note the position of each faulty pixel and take a photo: it makes the claim easier. For online purchases, you can usually return the screen within the withdrawal period anyway.

Found a defect and not sure it justifies a return? Describe it here.