This grey screen test fills your display with flat grey, a gray screen in American spelling, at 5, 10, 25, 50 or 75% brightness, plus the 18% middle grey that photographers use. A mid grey is the best color for judging how evenly a screen lights up: uneven backlight, cloudy patches, darker corners, vertical bands, the dirty screen effect and faint OLED burn in all show more clearly on grey than on white or black. It works on LCD and OLED monitors, laptops and TVs in Chrome, Edge, Safari and Firefox.
How to run the grey screen test
- Darken the room and set your screen to the brightness you normally use.
- Start with 50%. Click the preview, tap it, or press F.
- Sit at your normal distance and look at the whole screen, not one spot. Then move your head slowly left and right.
- Press the left arrow, or swipe right, to step down to 25%, 10% and 5%. Faults in dark scenes show up there.
- Try 75% for faint shapes of logos or taskbars that might be burned in.
- Press Esc or double tap to exit.
What each grey level shows
| Grey level | Hex and RGB | What to look for |
|---|---|---|
| 5% | #0D0D0D, 13 13 13 | Near black evenness, OLED blotches and bands in dark scenes |
| 10% | #1A1A1A, 26 26 26 | Clouding and backlight patches on LCDs |
| 25% | #404040, 64 64 64 | Vertical or horizontal bands, uneven dark greys |
| 50% | #808080, 128 128 128 | Dirty screen effect, darker corners, color tint across the screen |
| 75% | #BFBFBF, 191 191 191 | Faint burn in and image retention on bright backgrounds |
| 18% card | #777777, 119 119 119 | A neutral middle grey background for color work |
Darker corners and the dirty screen effect
On 50% grey, most panels are slightly darker toward the corners. This is called vignetting, and a mild amount is normal. Dirty screen effect looks like faint smudges or vertical stripes across the middle, as if the screen needed cleaning. It comes from small differences in the panel and backlight, not from dirt, and it shows most when a camera pans across a flat area such as a sky, a sports field or an ice rink.
What to do: look at the same grey from your normal seat, not up close. If you only see it on a test screen, it is normal for that panel. If it distracts you in films, games or sports on a new screen, use the return window, because it cannot be fixed with settings. Lowering the backlight brightness can make it less noticeable on some LCDs.
Clouding and backlight patches
Brighter cloudy areas on 10% and 25% grey, usually near the edges, come from the LCD backlight leaking unevenly. They show in dark films and night scenes in games. Check pure black too with the black screen, and use the backlight bleed test for a full check of edge bleed.
Bands and lines
Wide vertical or horizontal bands of slightly different grey are a panel fault called banding or mura. Thin lines one pixel wide that stay on every color are a panel or cable fault. Reseat the cable first. If lines also show in the monitor's own on screen menu, the panel is at fault and needs warranty service. Bands that only appear in smooth color gradients, rather than on flat grey, are a different issue caused by limited color depth, which a monitor color test with gradients shows.
Burn in and image retention on OLED
On an OLED, pixels that showed the same bright image for a long time, such as a taskbar, a news ticker or a game's map, wear faster than the rest. On 50% and 75% grey their outline shows as a faint shape.
- Temporary image retention fades within minutes to hours. Play varied video or leave the screen off for a while and check again.
- Permanent burn in stays. Run the panel's pixel refresh or panel care cycle from its menu, which can reduce mild cases.
- Prevent it with an auto hiding taskbar, a dark theme, a short screen timeout, and a black screen instead of a static desktop when you step away.
For a closer check, run the oled burn in test.
A grey screen you did not choose
- Windows shows only grey after signing in: press Win + Ctrl + Shift + B, or start explorer.exe from Task Manager, then update the graphics driver.
- A Mac starts to a grey or blank screen: start in Safe Mode. On a Mac with Apple silicon, shut down, hold the power button until the startup options appear, select your disk, hold Shift and click Continue in Safe Mode. On an Intel Mac, hold Shift right after turning it on.
- A TV or monitor shows a plain grey screen: check the input source and cable, then follow the monitor no signal steps.
What a grey screen test in a browser cannot do
Your eyes judge the result, so it is a visual check rather than a measurement. Review sites measure uniformity with a colorimeter at many points. The grey levels are exact pixel values, but how bright each one looks depends on your screen's gamma and settings. For a full set of panel checks, the monitor test covers pixels, colors and motion.
Grey screen questions
What is a grey screen test?
A full screen of flat grey that shows how evenly your display lights up. Because grey is neither bright nor dark, darker corners, cloudy patches, vertical bands and faint burned in images are much easier to see on it than on white or black.
What percentage grey should I use?
Start with 50% for the overall picture: dirty screen effect, darker corners and tint. Then check 25% and 10% for clouding and bands in dark scenes, and 5% for near black evenness on OLED screens. Use 75% to look for faint burn in on bright backgrounds.
Is some dirty screen effect normal?
Yes. Almost every LCD and many OLED panels show slight unevenness on 50% grey, especially toward the edges. It matters when you notice it in normal use, for example as stripes while a camera pans across a sky or an ice rink in sports. If it is that visible on a new screen, return or exchange it.
How do I fix a grey screen after login on Windows 11?
Press Windows + Ctrl + Shift + B to restart the graphics driver. If the desktop does not appear, press Ctrl + Shift + Esc, choose Run new task and start explorer.exe. Then update the graphics driver from NVIDIA, AMD or Intel. The black screen page covers the rest of the fixes, since both problems have the same causes.
Why do photographers use 18% grey?
A surface that reflects 18% of light looks like a middle grey to our eyes, halfway between black and white. Camera light meters are designed around a similar mid grey. The 18% card shade here, #777777, is that middle grey on a standard screen, which makes a neutral background for judging colors.