Professional online black screen test tool for detecting dead pixels, stuck pixels, backlight bleeding, and screen uniformity issues. Test your display with a pure black screen to identify defects on OLED, LCD, and LED screens. Works on smartphones, tablets, monitors, and TVs.
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Click to enter fullscreen mode and display a pure black screen for testing
A black screen test displays a pure black image across your entire screen, allowing you to identify various display defects that are difficult to see under normal conditions. On OLED displays, a black screen reveals true black performance since each pixel can turn off completely. On LCD and LED screens, it helps identify backlight bleeding and IPS glow issues.
This test is essential for anyone who wants to verify their display quality, whether you've just purchased a new device or want to check for issues on an existing one. Dead pixels appear as bright dots on a black background, while backlight bleeding shows as light patches around the edges or corners of the screen.
Click the 'Start Black Screen Test' button to enter fullscreen mode with a pure black display.
Look carefully for any bright spots, light patches, or colored dots against the black background. These indicate display defects.
Pay attention to edges and corners where backlight bleeding commonly occurs. Also check the center for dead or stuck pixels.
If you find defects, note their location and severity. Press ESC or click to exit the test mode.
Appear as bright white or colored dots that don't turn off. These are pixels that have permanently failed.
Show as red, green, or blue dots on black. These pixels are stuck in an 'on' state and may be fixable.
Visible as light patches around edges or corners on LCD screens. Caused by uneven backlight distribution.
Uneven brightness or color across the display. More noticeable on dark or black backgrounds.
Dead pixels are permanently off and appear as black dots on white or colored backgrounds, but may appear as bright dots on black if the subpixel is stuck on. Stuck pixels remain in one color (usually red, green, or blue) and can sometimes be fixed with pixel-fixing software or pressure methods.
LCD screens use a backlight that's always on, so they can't produce true black like OLED displays. This is normal and not a defect. However, if you see uneven patches of light, that indicates backlight bleeding, which is a quality issue.
Minor backlight bleeding is common in LCD displays and usually cannot be fixed. However, severe bleeding may indicate a manufacturing defect. If your device is new and has significant bleeding, you may want to contact the manufacturer for a replacement.
This varies by manufacturer. Many have a minimum threshold (often 3-5 dead pixels) before they consider it a defect covered under warranty. Check your manufacturer's dead pixel policy for specific details. A single dead pixel in the center of the screen is often more bothersome than several near the edges.
Ready to test your display for dead pixels and backlight bleeding? Start the black screen test now.