Screen Bleeding Test
Check your display for backlight bleed, IPS glow, and clouding. It floods the screen with pure black — turn off the lights, then scan the edges and corners for any light leaking through.
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Bright light leaking from the edges and corners — stays fixed when you move your head.
A warm corner glow on IPS panels that shifts and fades as your viewing angle changes.
Uneven blotchy patches across the panel, easiest to see on the near-black grey screens.
How it works?
An LCD makes black by twisting its liquid crystals to block an always-on backlight, but that blocking is never perfect — light leaks past the panel layers, usually at the clamped edges and corners. A full black screen in a dark room is the harshest background for that leak, so any bleed or uneven glow stands out. The near-black grey screens add a touch of brightness that makes broad, blotchy mura easier to spot than pure black does.
Bleed vs IPS glow vs clouding
- Backlight bleed — bright light leaking at the edges or corners that stays fixed as you move your head. Some is normal; large patches aren't.
- IPS glow — a warm corner haze on IPS panels that shifts and fades with your viewing angle. Normal for the panel type, not a fault.
- Clouding / mura — uneven, blotchy lighter areas across the panel, often easiest to see on a near-black grey field.
For an accurate test
- Switch off the room lights — bleed is only fairly judged in the dark.
- Clean the screen first so dust and smudges aren't mistaken for leak.
- Let your eyes adjust for a minute, then view straight-on from a couple of feet back.
- Turn brightness up to reveal faint bleed, but judge how much it bothers you at your normal brightness.
- Move your head around to separate fixed backlight bleed from angle-dependent IPS glow.
- Test a new monitor early, while you're still inside the return window.