Backlight bleed test.
Backlight bleed is the warm glow that escapes around the edges of an LCD in a dark room. This test fills your display with true black and three near-blacks, so escaping light has nowhere to hide — on any monitor, TV, laptop or phone.
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Need RGB channels? Full pixel test →Nº 01 — Procedure
Four steps.
Two minutes. A verdict.
Blackout the room
Turn off every light and give your eyes two to three minutes to adapt. Ambient light is camouflage for bleed — the glow only surrenders in full darkness.
Max the brightness
Bleed scales with the backlight. Testing at 40% brightness hides it; testing at 100% shows it exactly as it will glow during dark movie scenes.
Cycle the shades
Run the sequence and give each shade thirty seconds. Watch the edges and corners, not the center. Pure black is the classic revealer; the near-blacks separate bleed from panel-uniformity issues.
Rate and document
Use the severity scale below to judge what you saw. If it's strong or severe: photograph the screen straight-on at default exposure, and keep the photos for the warranty claim.
Your eyes need two to three minutes of darkness before they can see faint glow. Run the sequence once, wait, then run it again — the second pass always shows more than the first.
Nº 02 — Differential
Backlight bleed
or IPS glow?
Half of all "bleed" reports are actually IPS glow — a different phenomenon with a different verdict. The widget below shows both, exaggerated for clarity. Drag the handle to compare against a clean panel.
In real life, the tell is motion: lean left and right in front of your screen. IPS glow shifts and shrinks as you move — backlight bleed stays exactly where it is.
Nº 03 — Severity scale
How much bleed is normal?
Rate what you actually saw during the test — not what you fear you'll see. Then read the verdict.
Nº 04 — Causes & remedies
Why it happens,
what actually helps.
Why it happens
Assembly tolerance
An LCD is a stack of layers clamped into a frame. Tiny gaps in that stack let the backlight peek around the edges.
Bezel pressure
A frame pressed too tightly against the panel squeezes light out at the corners — the brighter the backlight, the more escapes.
Shipping flex
A panel that flexed in transit can sit unevenly in its frame for the rest of its life. This is why bleed often appears on brand-new monitors.
What helps — and what doesn't
Lower brightness
Bleed scales with the backlight. A few steps down hides a surprising amount.
Local dimming
On TVs and mini-LED displays that support it, dimming zones switch off behind dark areas entirely.
Warranty replacement
The only true fix. Bright patches visible in normal viewing qualify; quote straight-on photos at default exposure.
Massage & pressure tricks
Rubbing the panel risks bruising it worse than the bleed you're treating.
Heat guns & hair dryers
You're one slip away from a delaminated panel and a voided warranty.
Confirmed bleed on an LCD? On OLED it can't happen at all — each pixel makes its own light and switches off for black. See the OLED comparison →
Nº 05 — Questions
Asked, answered.
Backlight bleed is light from an LCD's LED backlight escaping around the edges of the panel assembly. It shows up as a warm glow along the edges or corners when the screen displays dark content in a dark room. OLED screens have no backlight, so they are immune.
Turn the lights off, set brightness to 100%, and display a fullscreen pure black image — this page's test does it in one click. Watch the edges and corners for 30 to 60 seconds, then compare against near-black shades to confirm.
Yes. Virtually every LCD panel leaks a small amount of light, and manufacturers set tolerance thresholds before a panel counts as defective. Faint edge glow visible only in a dark room is considered normal; bright patches visible in normal viewing are not.
Backlight bleed sits along the edges, stays constant no matter where you sit, and can affect any LCD. IPS glow appears in the four corners, shifts or shrinks as you change viewing angle, and is inherent to IPS panel technology rather than a defect.
Not with software. Lowering brightness makes it less visible, and enabling local dimming helps on TVs that support it, but the only real remedy is panel replacement under warranty. Massage and heat fixes from video tutorials risk making it worse and voiding coverage.
No. OLED pixels produce their own light and switch off completely to display black, so there is no backlight to leak. If you see glow on an OLED in a dark room, it's usually room reflections or the panel's near-black rendering, not bleed.