Black Screen Test
Inspect a black surface for light leakage and bright stuck pixels.
Before you start
Start to show a solid black surface. Use it briefly to look for bright pixels, reflections, or light in dark areas, or simply as a temporary black screen.
Tap or click the plain surface to show the controls. Hide controls for a clear view; tap to recover them, or press H or Tab. Exit with the Exit button or Escape.
How to use this test
- Start the utility to display one solid black image.
- Hide controls for an unobstructed dark surface. Look briefly for bright dots or reflections at normal brightness.
- Use Tab or H to recover controls, then Exit or Escape to return.
What to look for
This utility sends CSS black to the display. It gives you a plain dark background for checking bright dots and observing the appearance of LCD glow or OLED black in your surroundings. For a guided LCD light-leak inspection, use the related Backlight Bleed Test.
Know the limitations
CSS black does not turn the display off or measure its black level. Reflections, local dimming, panel technology, viewing angle, HDR processing, and room lighting affect the appearance. The page cannot identify your panel technology or certify contrast.
If black still looks bright
Compare reflections and viewing position before drawing a conclusion. The powered display may process black differently depending on its panel and dimming settings. For a repeatable LCD edge-light comparison, use the dedicated bleed inspection rather than interpreting one black view as a verdict.
Common questions
Does a black screen switch my monitor off?
No. The monitor remains powered and receives a black image. LCD backlights may remain on; OLED pixels and display processing behave according to the device’s settings.
Why can I still see light on black?
It may be room reflections, LCD backlighting, IPS glow, or the display’s settings. Compare viewing positions and normal content before drawing conclusions.