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Panel & Backlight

Brightness Uniformity Test

50% gray field and a 9-zone grid to spot uneven backlighting.

How to use

  1. 1Click Start and view the gray field full-screen.
  2. 2Use ← / → to toggle the 9-zone grid overlay.
  3. 3Compare the brightness of the center against each corner.
  4. 4Press Esc to exit.

FAQ

How much variation is acceptable?

Good monitors stay within roughly 10% brightness variation across the panel. Larger differences show as visibly darker corners or brighter hotspots.

Tips

  • Compare the center against each corner one at a time rather than scanning the whole field.
  • Take a photo and even out exposure — your eyes auto-adjust and hide real differences.

Related tests

Dead Pixel TestFull-screen solid colors to find dead, stuck, and bright pixels.Backlight BleedReveal LCD backlight leakage and IPS glow in a dark room.Blooming TestA bright object on black to judge local-dimming halos.Burn-in TestFull-screen fields and a checkerboard to reveal OLED burn-in.

Related guides

Learn more about what this test reveals and how to act on the results.

The Complete New-Device Screen Test ChecklistA 10-minute routine to inspect any new laptop, monitor, phone, or TV before the return window closes.How to Test a Monitor Before (and Right After) BuyingWhat to check in the store and at home so you don't keep a monitor with dead pixels, bleed, or the wrong refresh rate.How to Test a New TV for Dead Pixels and UniformityUse your TV's browser or a phone to run solid-color and gray tests that reveal panel defects and dirty-screen effect.How to Set Up a Monitor for Photo EditingGamut, brightness, calibration, and room lighting choices that keep your edits looking right everywhere.