Mac Screen & Dead Pixel Diagnostic Test
Test your MacBook, iMac, Studio Display, or external monitor for stuck pixels, dead pixels, backlight bleed, and Mini-LED zone uniformity in full screen.
Backlight Bleed & Mini-LED Dimming
Look closely across the display for black dots, discolored pixels, or uneven glow.
Is your MacBook screen turning completely black randomly?
If your screen turns dark while the keyboard lights and trackpad click are still working, it is NOT a dead pixel. This is a hardware T-CON thermal sleep lock common on Apple Silicon (M1, M2, M3).
Dead Pixel vs Stuck Pixel
A dead pixel is permanently off and appears black on a pure white screen. A stuck pixel is stuck on one color (red, green, or blue) and remains visible on a pure black background.
Liquid Retina XDR Mini-LEDs
14" and 16" MacBook Pro models feature thousands of local dimming zones. Use the 50% Neutral Gray test to detect any uneven halos, color banding, or dirty screen effect (DSE).
Cleaning Before Testing
Tiny specks of dust or screen smudges can easily be mistaken for sub-pixel defects. Gently wipe your screen with a dry microfiber cloth before launching the fullscreen test.