Screen Uniformity Test

How to use the uniformity test

A well-made panel shows a flat gray field as the same brightness and tint from edge to edge. Uneven backlighting, clouding, and tint shifts are hardest to hide at these middle levels, so this test shows three grays: Dark (#404040), Mid (#808080), and Light (#BFBFBF).

1. 1

   Dim the room a little and turn off night mode and blue-light filters.

2. 2

   Open the field full screen and step back to your usual distance or a little farther. Uneven areas are easier to see at a glance than up close.

3. 3

   Try all three levels. Press → or Space in fullscreen, or use the level buttons.

4. 4

   Turn on the grid if it helps to compare the nine zones: center against corners, left against right.

What to look for

Brightness falloff: corners or edges that look darker than the center. Clouding: soft brighter or darker blotches. Tint drift: areas that lean pink, green, or blue instead of staying neutral. The Dark level usually shows clouding best; Mid and Light show falloff and tint.

Some unevenness is normal, especially on large or edge-lit LCD panels. Compare what you see with the manufacturer's warranty or return terms; Is Backlight Bleed Normal? explains how makers judge leaks and clouding, and How to Test a Monitor shows where this test fits in a full check. For a finer adjustable gray, use the Gray Screen; for leaks at the edges, the Backlight Bleed Test.

Avoid false alarms

Let the display warm up for several minutes first; brightness and tint can shift slightly while a panel warms up. Mind the viewing angle: on a large screen you see the edges at an angle, which alone can make them look darker, especially on VA and TN panels. Judge by eye, not from a phone photo, which can exaggerate or hide unevenness.