Backlight Bleed vs IPS Glow: How to Tell Them Apart

Byscreentesteradmin

You switch off the lights, open a black screen, and see light in the corners. Is your new monitor faulty? Maybe, or maybe not. Two different things cause light on a black LCD screen: backlight bleed and IPS glow. One is a manufacturing flaw, the other is normal for the panel type. Here is how to tell which one you have.

What backlight bleed is

LCD monitors and laptop screens light the panel from behind or from the edges. The liquid crystal layer blocks that light to make black. If the panel is pressed unevenly in its frame, or the layers are not sealed perfectly, light leaks around the edges. That leak is backlight bleed.

  • It usually appears at the edges and corners.
  • It looks like patches or streaks of lighter light.
  • It stays in the same place when you move your head.
  • It can be white, yellow or bluish.

What IPS glow is

IPS panels have great colors and viewing angles, but when you look at a dark image from an angle, the panel lets some light through. That is IPS glow.

  • It shows mostly in the corners, often stronger in the lower corners on large screens.
  • It has a silvery, orange or purple tint.
  • It changes or moves when you change your viewing angle or sit further back.
  • Every IPS panel has some. It is not a defect.

The 30-second test

  1. Open our screen tester and choose Backlight bleed. Dim the room and set brightness to maximum.
  2. Sit at your normal distance and note where the light is.
  3. Move your head left, right, up and down, then step back a meter or two.
  4. Light that moves, fades or changes color is IPS glow. Light that stays put in the same shape is bleed.

Tip: take a photo with your phone at normal exposure, not a long night-mode exposure, which makes every screen look terrible.

VA and OLED screens

VA panels have less glow but can show bleed and “clouding”. OLED screens have no backlight at all, so they cannot have bleed or IPS glow. On OLED, use the gray uniformity fields instead to check for tint or banding.

How much bleed is acceptable?

A faint glow in one corner that you only see on a black screen in a dark room is common and rarely accepted as a fault. Return or report the screen if bleed is:

  • visible in normal dark scenes in films or games,
  • bright enough to see with the room lights on,
  • large patches or streaks along a whole edge.

Can you reduce bleed?

Lower the brightness, which makes bleed less visible. Some people report that slightly loosening the screws on the back of a monitor reduces pressure on the panel, but that can void your warranty and is not recommended. If bleed bothers you, use your return window. Check it on day one with the new monitor checklist.