DeviTestBacklight bleed vs IPS glow
Both show up as light patches on a dark screen, but one is a normal trait of IPS panels and the other can be a defect. One simple test tells them apart.
What is backlight bleed?
Light from the backlight leaks around the edges of the panel, usually because of uneven pressure from the frame. It looks like bright, often yellowish patches at the edges or corners and stays the same from any viewing angle.
What is IPS glow?
A silvery or slightly warm glow caused by how IPS panels handle light at an angle. It's strongest in the corners, most visible on large screens viewed up close, and it changes or moves when you move your head.
The simple test
- Dim the room lights and open the black screen test.
- Set brightness to the level you normally use — maximum exaggerates everything.
- Sit at your normal distance and look at the corners.
- Move your head left, right, up and down. If the glow shifts or fades, it's IPS glow. If the patch stays fixed, it's bleed.
When is it a defect?
Some IPS glow and light bleed is normal on most LCDs. It becomes a problem when strong patches are clearly visible in normal dark scenes at normal brightness. Many sellers and manufacturers accept returns in that case, so test right after buying.