Screen Uniformity Test

Likely a dead pixel

A pixel that stays black on white, red, green and blue backgrounds is receiving no power or no signal. True dead pixels are a hardware fault and software cannot switch them back on.

Next step: Count the dots and note their position, then check the return window or the manufacturer dead pixel policy for your device. A report makes the conversation with the seller easier.

Likely a stuck subpixel

A dot that glows in one color on a black background is usually a subpixel stuck on. Unlike dead pixels, stuck pixels sometimes recover after rapid color cycling.

Next step: Try the Stuck Pixel Fixer for 10–20 minutes, then re-run the test. If the device is new, a return or exchange is still the safer option.

Backlight bleed or IPS glow

Uneven light around edges and corners on a dark screen comes from the backlight, not from individual pixels. IPS glow shifts when you change your viewing angle; backlight bleed stays in place.

Next step: Re-test in a dim room at your normal brightness and move your head side to side. Mild edge glow is common on LCD panels; strong bleed on a new device can justify an exchange.

Gray uniformity issue

Bands or large dull patches that appear on mid-gray backgrounds are a panel uniformity problem, sometimes called the dirty screen effect. OLED panels can also show faint vertical banding in dark gray.

Next step: Confirm with several gray levels at 50–100% brightness. Mild non-uniformity is normal; strong banding visible in everyday content is worth reporting to the seller.

Burn-in or image retention

A leftover outline of a logo, taskbar or scoreboard is image retention. On OLED screens it can become permanent burn-in; on LCD it usually fades after the screen shows varied content.

Next step: Run the burn-in check to see how visible the retention is at different gray levels. If it fades within hours it was temporary retention, not burn-in.

Dust or a smudge — not a pixel defect

Dust, fibers and fingerprints sit on top of the glass and move or vanish when wiped. A pixel defect never moves and never changes size.

Next step: Clean with a dry microfiber cloth and re-run the test. If the spot is gone, your panel is fine.

Touch digitizer issue

Touch input is handled by a separate layer from the pixels. A screen can look perfect and still have dead touch zones, often after a drop or screen replacement.

Next step: Map the unresponsive area with the touch grid test. Restart the device and remove any screen protector before concluding it is a hardware fault.

No visible pixel defects

If every full-screen color looked even with no dots, bands or glow, your panel passed the visual check.

Next step: Save a dated report as proof of condition — useful for warranty windows, selling a device or verifying a used purchase.