Clean first, then test
A large share of suspected dead pixels are dust, dried droplets or lint. Wipe with a microfibre cloth dampened with distilled water or screen cleaner, let it dry fully, and only then start the test. This one step prevents embarrassing support tickets.
The colour order that finds each defect type
Each colour reveals a different fault, so run them in this order:
- Black: stuck-on pixels and hot pixels glow against it — the most obvious defects
- White: dead pixels and dim subpixels appear as dark dots; dust is also most visible here
- Red, green and blue: reveal subpixel faults, which look like a coloured fringe and are usually only visible on white backgrounds
- Mid grey: imperfections that vanish at extremes sometimes show here
Look the right way
Move your eyes in horizontal bands rather than staring at the centre, and check the corners and edges first — defects cluster there on cut panels. Look from about 30 cm for the detailed pass, then step back to a normal viewing distance and check again, because a pixel you cannot see from where you sit does not matter in practice.
Documenting the defect
One photo of the whole screen to show the location, one close-up macro to show the defect itself, plus the panel's model and serial number and a description of the test method. Manufacturers apply count-and-position policies — often zero tolerance in the centre, a small number allowed at the edges — so knowing your model's policy before you write changes what you ask for.