Black Screen Test
A pure black full-screen reveals backlight bleed, IPS glow and bright stuck pixels, and shows how deep your OLED's blacks really are. Click to go fullscreen, Esc to exit.
Click the button to fill your entire screen with solid black. Click anywhere or press → to cycle colours, and Esc to exit.
What a black screen reveals
A solid black field exposes anything that glows when it shouldn't:
- Backlight bleed — bright patches near the edges of an LCD where light leaks past the panel. Best seen in a dark room.
- IPS glow — a cornerwash of light on IPS panels that shifts as you move your head. Mild glow is normal; large bright clouds are not.
- Bright stuck pixels — pixels stuck on a colour show as coloured dots against black.
OLED true-black check
On an OLED or AMOLED display, black pixels switch off completely, so a black screen should look like the monitor is powered down — no glow at all. If you see any backlight, the panel is LCD, not OLED. This is also a quick way to check for OLED faults: uneven dark greys or faint vertical lines on near-black can be early signs of panel wear.
Test in a dark room
Backlight bleed and IPS glow are only visible with the lights off. Turn brightness up, darken the room, and look at each edge and corner. A little glow on IPS is expected; pooling bright patches on a new monitor are a valid reason to request a replacement.
Next steps
Black finds bright faults; white finds dark ones. Run the full dead pixel test to cycle every colour, and if you see coloured dots that persist, compare them against our guide on dead pixels vs stuck pixels.
Frequently Asked Questions
What does a black screen test show?
It reveals anything that glows when it should be dark: backlight bleed and IPS glow around the edges of an LCD, and bright stuck pixels that show as coloured dots against black.
How do I check OLED true blacks?
On an OLED the black pixels turn fully off, so the screen should look powered down with no glow anywhere. Any visible backlight means the panel is LCD, not OLED.
What is backlight bleed?
Backlight bleed is light leaking past the edges of an LCD panel, seen as bright patches on a black screen in a dark room. Some bleed is common; large bright pools on a new monitor justify a replacement.
What is the difference between IPS glow and backlight bleed?
IPS glow is a corner wash of light that changes as you move your head and is normal on IPS panels. Backlight bleed is fixed bright patches that stay put regardless of viewing angle.
Why should I test in a dark room?
Backlight bleed, IPS glow and faint stuck pixels are only visible against true darkness. Turn brightness up, switch the lights off, and inspect each edge and corner.
Can a black screen find stuck pixels?
Yes — a pixel stuck on a colour shows clearly against black. To catch every type of fault, follow up with the full dead pixel test, which also uses white and each primary colour.