Black Screen Test (Free Online Light Leak Checker)
Inspect your display for backlight bleeding, light leakage, and IPS glow using our fullscreen black canvas diagnostics.
Interactive Black Canvas Levels
Choose your preferred black luminance level before starting fullscreen mode:
Select a black shade and click 'Start Fullscreen'. Scan bezel borders for light leaks.
What Can You Find with a Black Screen Test?
A full-screen black display reveals how well your screen blocks light. It is ideal for identifying backlight leakage and manufacturing defects:
1. Backlight Bleed
Visible as localized white or yellow light patches spilling from monitor edges. It occurs when display frame pressure warps the glass layers, allowing backlight to bypass the liquid crystals.
2. IPS Glow
A common optical trait of IPS panels. Corners emit a slight silver or gold glow when viewed from an angle. Unlike light bleed, IPS glow changes shape and density as your viewing position shifts.
3. Hot or Stuck Pixels
Tiny bright colored dots (red, green, blue, or white) that emit full luminance against the dark canvas, indicating sub-pixel transistor failure.
How to Inspect Backlight Leakage
- Reduce Room Lighting: Screen light leaks are difficult to see under bright office lighting. Turn off overhead lights to reveal dim light leaks.
- Compare Viewing Angles: Tilt your head. If the glow shifts and fades, it is IPS glow. If the glow stays bright and fixed, it is physical backlight bleeding.