Gray Screen

How to use a gray screen

A gray field lights the red, green, and blue subpixels at the same level, somewhere between off and fully on. Many display faults are hardest to hide at these middle levels: a panel that looks fine on pure white or pure black can show clouds, darker corners, or a color tint on gray.

1. 1

   Pick a level. Start with Mid (#808080), then try Dark (#404040) and Light (#BFBFBF). The slider sets any level from 0 (black) to 255 (white), and the label shows the exact color.

2. 2

   Open it full screen. The controls stay on the page, so only the gray fills the display.

3. 3

   Turn off color filters. Night mode and blue-light filters tint gray toward yellow, which looks like a fault.

4. 4

   Step back. Look at the whole screen from your usual distance. Uneven areas are easier to see at a glance than up close.

What a gray screen can reveal

Uneven backlighting: brighter or darker patches, clouding, or darker corners. They often show best at the dark and mid levels.

Tint shifts: areas where the gray leans green, pink, or blue instead of staying neutral from edge to edge.

Panel dirt: a faint fixed pattern of blotches or lines that stays in place when you move content around. It is sometimes called the "dirty screen effect" and is most visible on large areas of mid gray.

Some unevenness is normal on many displays, so compare what you see with the manufacturer's warranty terms before deciding a panel is faulty. For the extremes, use the White Screen and the Black Screen; for a structured check, the Screen Uniformity Test.

This screen's default value has its own #808080 color page, with its RGB and HSL values and its contrast against black and white.