Backlight Bleeding Test

On a dark screen, light that leaks from the edges of the backlight becomes visible. Black and a few near-black levels make bleed, glow and clouding easy to spot.

Pure black. Look for brighter patches along the edges and in the corners.

Runs entirely in your browser. Nothing is uploaded or stored.

How to use

  1. Dim the room or wait until it is dark. Bleed is invisible in a bright room.
  2. Set the display brightness to the level you normally use.
  3. Press Start test and look at the black screen from directly in front.
  4. Step through the near-black levels. Clouding often shows more clearly at 2 to 5 percent gray than at pure black.
  5. Move your head to the sides. Glow that changes with viewing angle is IPS glow, not bleed.

What this test can detect

  • Backlight bleed: brighter patches along the edges and corners that stay put when you move.
  • IPS glow: a silvery or warm sheen in the corners that shifts or fades with viewing angle.
  • Clouding: irregular lighter areas anywhere on the panel.
  • Uneven illumination: one side or the center visibly lighter than the rest.

Important

  • Almost every LCD shows some bleed or glow in a dark room. Mild, even glow in the corners is normal; large bright patches are not.
  • OLED and other self-emissive displays show true black and are not affected by backlight bleed.
  • Cameras exaggerate bleed. Judge with your eyes at normal viewing distance, and compare with the manufacturer's return policy if it looks severe.