A new monitor, a dark room, a black test image, and the corners glow. Whether that is a defect depends on which of several distinct phenomena it is, and the distinction is worth knowing before starting a return.
What changed in 2026
- OLED adoption removed backlight problems. Self-emissive panels eliminated bleed and glow entirely, introducing different concerns.
- Mini-LED backlights improved local control. Zone-based backlights reduced visible unevenness on LCDs.
- Return policies stayed inconsistent. Manufacturer thresholds for uniformity defects varied widely.
- Panel variation persisted. Units of the same model continued to differ noticeably.
Telling them apart
| Phenomenon |
Appearance |
Defect? |
| IPS glow |
Corner glow that moves as you shift position |
No — inherent |
| Backlight bleed |
Bright patches at edges, fixed in place |
Some is normal |
| Clouding |
Uneven blotches across the panel |
Excessive amounts are |
| Dirty screen effect |
Faint vertical banding on uniform greys |
Varies by tolerance |
| Dead or stuck pixels |
Individual points, always wrong |
Per manufacturer policy |
IPS glow is the one most often mistaken for a defect. It is a property of how the panel type handles light at an angle, so corners appear to glow because you view them off-axis. The test: move your head. Glow that shifts or disappears as your position changes is IPS glow, and every IPS panel has it.
Backlight bleed is light escaping around the edges of the panel, typically from uneven pressure in the assembly. It stays in the same place regardless of viewing position, which distinguishes it from glow. A small amount at edges is normal; large bright patches are a manufacturing problem.
Clouding is irregular patches across the panel from uneven backlight diffusion. Small amounts are common; pronounced clouding visible in normal content is a defect.
Dirty screen effect shows as faint banding on uniform mid-grey — most visible in sports coverage or panning shots on a uniform background. Nearly all LCDs have it to some degree.
Test sensibly
Most uniformity complaints come from testing in conditions nobody uses a monitor in.
Test in a normally lit room. A black image in a completely dark room is the most punishing possible condition and does not represent use. Ambient light raises the black floor, and most bleed becomes invisible.
Look at real content, not just black test screens. If unevenness is not visible in what you actually do, it is not affecting you.
Sit at your normal distance and position. Close inspection from a foot away finds things that do not exist at working distance.
Let it warm up. Uniformity changes as the panel reaches operating temperature; test after twenty minutes or so.
Check brightness at your setting. Maximum brightness exaggerates bleed considerably, and most people work far below it.
If it fails those conditions — visible in normal content, at normal brightness, in a normally lit room — it is worth returning. If it only appears on a black screen in a dark room at full brightness, most manufacturers will not accept it, and reasonably so.
The panel lottery
Uniformity varies between units of the same model, sometimes considerably. Two monitors from the same production run can differ noticeably.
That has an implication people learn the hard way: exchanging a unit is a gamble rather than a fix. The replacement may be better, worse, or differently imperfect, and there is a real risk of ending up with something worse after several attempts.
The reasonable approach is to set a threshold — visible in normal use — and accept anything below it. Every panel has something, and pursuing perfection through repeated exchanges usually ends in frustration.
Dead pixel policies are the other place to check before buying. Manufacturers specify how many defective pixels constitute a warrantable fault, and the thresholds vary considerably. Some offer a zero-defect guarantee, which is worth something if it matters to you — see how to win a warranty claim for making a claim stick.
Common mistakes
- Mistaking IPS glow for bleed. Move your head to check.
- Testing on black in a dark room. Worst-case, unrepresentative.
- Testing at maximum brightness. Exaggerates everything.
- Testing before warm-up. Uniformity changes.
- Repeated exchanges. The lottery can go the wrong way.
- Ignoring the dead pixel policy before purchase. Varies widely.
- Judging from close inspection. Not the working distance.
FAQ
Do OLED monitors have these problems?
No backlight means no bleed, glow, or clouding. They have different characteristics — burn-in risk with static content, and different near-black behaviour.
Is some bleed always present on LCD?
Effectively yes. Edge-lit panels almost all show some, and the question is whether it is visible in normal use.
Will bleed get worse over time?
It can change as materials settle, sometimes improving and sometimes worsening. Significant change is uncommon.
How many dead pixels warrant a return?
It depends on the manufacturer's stated policy, which varies from zero-tolerance to several. Check before purchase rather than after.
Where to go next
For motion performance, read pixel response time. For claiming when a panel is genuinely faulty, how to win a warranty claim, and for sharing a display between machines, KVM switches.