Pure black uniformity check

Backlight Bleed Test

Detect uneven backlighting, clouding, and IPS glow on your monitor, laptop, or TV. Use a pure black background and adjust brightness to reveal imperfections.

BLACK TEST Double‑click to adjust brightness
100% ● Backlight

Why use this test?

A proper evaluation requires a controlled black level and the ability to see subtle luminance variations.

Reveal hidden bleed

Pure black exposes light leaking from edges, corners, or uneven zones that are invisible on bright content.

Adjustable brightness

Cycle through brightness presets (100% down to 0%) to simulate different backlight intensities and spot clouding.

Fullscreen mode

Expand the test area to fill your entire screen for an immersive, distraction‑free evaluation.

How to test properly

1
Dim the room lights
Ambient light can mask backlight bleed. Work in a dark or very dim room for the most accurate assessment.
2
Enter fullscreen
Click the Fullscreen button so the black area fills your entire display. This removes distractions and reveals edge bleed.
3
Cycle brightness levels
Double‑click the black area or press B to step through brightness presets. Lower percentages make the black background lighter, which can expose clouding.
4
Toggle glow (optional)
Press G or click the Glow button to add a very subtle base lift. This simulates a typical backlight‑on state and helps visualise faint bleed. For a strict black test, turn glow off.
5
Look for uniformity issues
Check corners, edges, and the center. Bleed appears as lighter patches, yellowish or bluish halos, or “flashlight” corners.
DeepBolt