Dead Pixel Test · Guide
Black Screen Test
A pure black field is the fastest way to spot anything that glows when it should not. Run it from the main test page — press Start Test there — and judge with your own eyes. This is a visual check only; nothing here repairs pixels.
What black reveals
On pure black, a stuck pixel still receiving power glows red, green or blue against the dark field, and backlight bleed shows as brighter patches near edges and corners. A truly dead pixel stays black here, so it is invisible on this colour — confirm it on white instead.
Dim the room slightly and use your normal brightness. Extreme brightness washes out faint glows; maximum dimming hides them.
How to run it
Press Start Test on the main page and step to the black field first. Press H to hide the controls and scan slowly, edges and corners last — that is where bleed and stuck dots hide.
On phones, rotate to landscape and swipe to black. Check notch and camera-cutout areas separately by rotating; no web page can inspect pixels hidden behind them.
What to record
Mark any glowing dot on the screen map on the main page, then download the text summary. It is labelled “User-reported visual inspection”: your record of what you saw, not proof of a defect and not a repair certificate.
Rule out dust first by tilting the screen and wiping gently with a soft, dry microfibre cloth. Dust looks blurry and shifts; a faulty pixel stays sharp, fixed and exactly one dot wide.
Honest limits: this guide helps you identify possible display problems with your own eyes. It cannot repair hardware pixels, diagnose your display automatically, or decide warranty claims. Read the limits.
Guide FAQ
What does a black screen test show?
Anything that glows on black: stuck pixels in red, green or blue, plus backlight bleed near edges. Dead pixels stay black on black, so check them on white.
Can it fix a stuck pixel?
No. This is a detection-only visual check with no flashing fixer and no repair instructions.