Backlight Bleed Test

Click Full Screen on the black test below, in a dark room at 30–50% brightness, and check the edges and corners for light leaking through. Works on any LCD monitor or TV — and helps you tell backlight bleed apart from harmless IPS glow.

New to this? Here’s the plain-English version.

What this test is

A pure-black full-screen image that reveals light leaking from the edges and corners of your monitor.

How it helps you

It tells you whether that glow you noticed in dark scenes is a real defect worth returning — or normal, harmless IPS glow.

What we’re checking

Whether light leaks through the panel edges (backlight bleed, a defect) or shifts as you move your head (IPS glow, normal).

Look for unevenly lit patches or light leaking from the edges.

For best results, view in a completely dark room at 30–50% brightness.

In a dark room, display this pure black screen and look for any areas that are not perfectly black. Light bleed is most common along the edges and in the corners.

Press F11 or Full Screen · ← → patterns · Esc to exit

How to Test for Backlight Bleed

Backlight bleed is only visible in dark conditions at the right brightness. Testing with the lights on at maximum brightness produces misleading results.

1Close the blinds or wait until dark. Bleed that isn’t visible in ambient light isn’t a practical problem.
2Set monitor brightness to 30–50%. Maximum brightness exaggerates bleed on any panel.
3Launch the full-screen black test above and let your eyes adjust to the dark for 30 seconds.
4Look at the edges and corners. Fixed bright patches are bleed; a shifting silvery glow that moves when you tilt your head is IPS glow.

Backlight Bleed vs IPS Glow — The Critical Difference

These look similar in photos but mean completely different things. Backlight bleed is a fixed bright patch — usually at the corners or along the top or bottom edge — that stays exactly where it is when you move your head. It is a manufacturing defect and, if severe enough to affect normal use, qualifies for warranty replacement.

IPS glow is a silvery or golden shimmer in the corners of IPS panels that shifts and changes intensity as you move your viewing angle. It is an inherent optical characteristic of IPS LCD technology — not a defect, and it cannot be returned or replaced.

Moves when you shift your head → IPS glow (normal).

Stays fixed regardless of viewing angle → backlight bleed (defect).

How Much Backlight Bleed Is Acceptable?

Some bleed is present on nearly all LCD monitors. The relevant question is whether it affects normal use. There is no universal published standard — manufacturers judge claims case by case.

Within tolerance

Visible only on a pure black screen in a dark room — not noticeable during movies, games, or desktop use at a normal viewing distance.

Return-worthy

Bright patches visible during dark game scenes or movies, or a zone bright enough to light up the desk in front of the monitor.

Backlight Bleed by Panel Type

Panel type	Bleed risk	Notes
IPS / Nano IPS	High	Most common bleed type; also exhibits IPS glow
VA	Low	Best black levels of any LCD type; minimal bleed
TN	Low–Medium	Minimal bleed, but poor contrast overall
OLED	None	No backlight — each pixel self-illuminates

VA panels have the best contrast and the least bleed of any LCD technology. If bleed-free black levels are critical, VA or OLED beats IPS. Found a fixed dot rather than an edge glow? That may be a dead pixel instead — run the monitor dead pixel test.

How to Reduce Backlight Bleed

Lower brightness. Dropping from 100% to 40–50% dramatically reduces bleed intensity.
Let the monitor warm up. Some panels show more bleed when cold; it often diminishes after 30 minutes.
Check panel tension gently. Very light pressure on a bleeding corner can temporarily reduce it — but firm pressure risks permanent damage.
Return if excessive. If bleed is obvious during dark scenes, start a return within the retailer’s window — the most effective remedy.

Backlight Bleed FAQ

What is backlight bleed?+

Backlight bleed is light from an LCD monitor's LED backlight leaking through the edges or corners of the panel. It appears as bright patches on an otherwise black screen and is caused by imperfect sealing between the backlight and the panel frame. OLED screens have no backlight, so they cannot exhibit it.

How do I test for backlight bleed?+

Display a pure black screen in a dark room with brightness at 30–50%, then look at the edges and corners for bright patches. Use the tool above — click Full Screen and let your eyes adjust for about 30 seconds before judging.

Is backlight bleed normal on IPS monitors?+

Some bleed is normal on most IPS panels, especially in the corners. Minor bleed only visible on a pure black screen in a dark room at 30% brightness is within normal range. Bleed visible during movies or gaming at normal brightness is excessive and worth returning.

Backlight bleed vs IPS glow — what's the difference?+

Backlight bleed is a fixed bright patch at the panel edges that stays put when you move your head. IPS glow is a silvery shimmer in the corners that shifts as you change viewing angle. IPS glow is an inherent panel characteristic, not a defect; backlight bleed is a defect.

Can backlight bleed be fixed?+

Usually not without professional panel disassembly. Lowering brightness reduces its visibility significantly, and letting the monitor warm up can help. If the bleed is severe on a new monitor, a return or warranty replacement is the correct remedy.

Bleed severe on a new monitor?

Check the brand’s dead pixel and panel policies before you file a claim.

Monitor Pixel Test Warranty Guide