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Dead Pixel Test

You unbox a new monitor or phone and want to make sure every pixel works before the return window closes. This tool auto-cycles through a sequence of full-screen colors — white, black, pure red, pure green, pure blue, a smooth grayscale gradient, and a high-contrast checkerboard — so you can scan every inch of your screen for dead, stuck, or dim pixels. Set the auto-advance speed to your liking, or step through manually with previous/next buttons. If you find a stuck (not dead) pixel showing a constant color, start the rapid-flash fix mode: it pounds through white, black, and primaries at high speed in an attempt to unstick the liquid crystal. Run it for 5–10 minutes and check again. It's not a magic cure, but it works often enough to be worth trying before you file for a replacement.

How to use

  1. Hit Full Screen to remove all UI — walk close to the display and scan carefully.
  2. Use the auto-cycle timer or the ← Prev / Next → buttons to step through every color.
  3. If you spot a stuck pixel, start Rapid Flash and let it run for 5–10 minutes, then re-check.
White
What's the difference between a dead pixel and a stuck pixel?

A dead pixel is permanently black — it never lights up. A stuck pixel shows a single color (red, green, blue, or white) because one subpixel is frozen in the 'on' position. Stuck pixels can sometimes be fixed with the rapid-flash mode on this page.

How does the rapid-flash stuck pixel fix work?

It rapidly cycles through white, black, red, green, and blue at high speed. The theory is that the fast color switching can unstick a frozen subpixel by repeatedly exercising the liquid crystal layer. Run it for 5–10 minutes and check again.

What colors should I test to find dead pixels?

Test white and black to spot any pixel that's permanently off or on. Then test solid red, green, and blue to check each subpixel individually. The gradient and checkerboard patterns help identify subtle issues like stuck subpixels or uneven brightness.

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