08LCD BACKLIGHT / DARK ROOM

Backlight Bleed & Blooming Test

In a dark room, use pure black to reveal light leaking at the edges, then a white window and a starfield to see how a local-dimming backlight halos around bright objects.

3 patterns
Fullscreen
No install

Browser-generated pattern · Not a laboratory measurement

PATTERNS / 03

Patterns in this test

Each pattern targets a different symptom. Start from the top, or jump straight to the one you need.

01

Pure black · #000000

Sit at your normal position. Fixed bright patches near the edges are bleed; glow that shifts as you move is IPS glow.
02

White window on black

Look around the white square: a gray halo or lit rectangle reveals local-dimming blooming or panel glow.
03

Starfield

Small bright points on black are the hardest case for local dimming. Watch for halos and raised black around each star.

PROTOCOL / 01—04

How to use this test

Keyboard and touch

→ · Space · Enter · click: Next pattern
←: Previous pattern
I: Keep the hint panel visible
Esc: Exit fullscreen
Tap or move: Show controls on touch screens and mice

01
Clean the screen gently and let it reach its normal operating temperature.
02
Set browser zoom to 100% and use the brightness and picture mode you normally use.
03
Start fullscreen mode. Each pattern shows a short hint about what to look at.
04
Observe from your normal position first, then move closer only to inspect a detail.

OBSERVE

What to look for

Fixed bright patches near the bezel
Glow that changes strongly as you move your head
Gray halos or lit rectangles around the white window and stars

INTERPRET

How to read the result

Backlight bleed stays near the edges; IPS glow changes with viewing angle; blooming is a halo that follows bright objects on local-dimming displays. Each has a different cause, and only bleed is usually a manufacturing tolerance issue.

LIMITS

Limits of a browser test

The result depends heavily on brightness, viewing angle, exposure and room darkness. It is not an absolute diagnosis or warranty assessment.

FAQ

Frequently asked questions

01Is IPS glow the same as backlight bleed?

No. IPS glow typically changes with viewing angle, while bleed is more fixed and often appears close to an edge or corner.

02What is blooming?

On Mini-LED and full-array local-dimming LCDs, the backlight zone behind a bright object also lights the dark pixels around it, creating a halo. More zones and better dimming algorithms reduce it; OLED has none.

03Should I photograph the screen?

A phone’s automatic exposure can greatly exaggerate glow. Judge with your eyes first and lock exposure if you need a comparison photo.

Backlight Bleed & Blooming Test

Patterns in this test

Pure black · #000000

White window on black

Starfield

How to use this test

Keyboard and touch

What to look for

How to read the result

Limits of a browser test

Frequently asked questions

Continue checking

Screen uniformity

OLED burn-in

Black screen