Backlight Bleed Test

The same black as the Black Screen

This test shows pure black, #000000, the same color as the Black Screen. What it adds is a method: how to set up the room, where to look, and how to tell a real leak from glow and reflections.

How to run the test

1. 1

   Make the room dark. Turn off the lights, close the curtains, and wait a minute for your eyes to adjust.

2. 2

   Set your usual brightness. Judge the display as you actually use it; at maximum, every leak looks stronger.

3. 3

   Open the field full screen and sit at your normal distance, looking straight at the center.

4. 4

   Check the edges and corners without moving closer. Then move your head a little to the side and watch what changes.

Bleed or glow?

Backlight bleed is light escaping around the edges of an LCD panel. It stays in the same place and keeps its shape when you move your head, and often looks like brighter patches or streaks along an edge.

Glow, common on IPS panels, is a haze in the corners that grows, fades, or changes tint as your viewing angle changes. It is a property of the panel type rather than a leak.

OLED displays have no backlight, so they cannot show bleed; a black OLED screen should look uniformly dark. On an OLED, the OLED burn-in guide covers what to check instead.

Judging what you see

Some bleed is common on LCDs. What matters is whether it is visible in normal use, on dark scenes at your usual brightness and room light. Phone photos exaggerate bleed a lot, so judge by eye. Is Backlight Bleed Normal? quotes the room lighting Dell and ASUS judge it under. Compare what you find with the manufacturer's warranty or return terms, and use the Screen Uniformity Test to check how evenly the rest of the panel is lit.

A single bright dot on the black field is not bleed but a stuck pixel: Dead Pixel vs Stuck Pixel explains the difference, and How to Test a Monitor shows where this test fits in a full check.