Backlight Bleed Test for LCD Dark-Field Observation
Use a black field and viewing-angle steps to observe LCD corners and edges.
Free to use. Runs in your browser. No signup.#000000 · RGB 0, 0, 0This is a smaller preview. Open the screen to fill your display and hide the page controls.
Inspect a black screen
Use a plain black field to look at bright patches and corners. Viewing angle, ambient light and your display settings affect what you see.
Before you start
- Reduce room reflections and use your normal display brightness. Avoid an extreme setting that changes how you usually view the screen.
- Sit centered in front of the display at your normal distance. Hide the controls so only the black field remains.
- Compare from slightly different angles. A patch that changes with your position may be viewing-angle glow; this check cannot diagnose the cause or measure leakage.
Press Escape to exit. Move the pointer or tap the screen to bring back the Exit button.
Inspect LCD edge light with a guided black-screen workflow
Follow a short setup and observation workflow on an LCD display. Use a dark room, note your normal hardware brightness, face the screen and show a pure black field. Then compare the same region from another viewing angle. This can help distinguish observations such as angle-dependent glow and fixed edge light, but the browser does not measure leakage or diagnose panel assembly. OLED has no separate LCD backlight, so its near-black behavior needs a different interpretation.
Ways to use the backlight bleed
Inspect LCD edges on a uniform dark field.
Compare a corner from a centered and changed viewing angle.
Separate room reflections from persistent dark-scene observations.
How to inspect LCD corners with a dark field
A controlled viewing setup is more informative than a black page viewed under changing conditions.
Prepare the room and note normal settings
Face the display and reduce room reflections. Keep a record of your ordinary hardware brightness rather than changing multiple settings while you inspect. Begin the guided black-field workflow only after reviewing its setup step.
Observe the full black field
Look at edges, corners and the center from your normal position. The page supplies #000000 content; hardware contrast, local dimming and picture processing still affect its appearance. A visible glow alone is not an automatic fault diagnosis.
Compare the same region from another angle
Return to the same area while shifting your viewing angle. Angle-dependent glow, fixed light and reflections can appear differently. Use the workflow explanation as an observation aid and consult the manufacturer for a panel assessment.
Continue with a focused check or a guided sequence: Monitor Test
Backlight Bleed: questions & answers
Everything you need before your next download.
Can this measure backlight bleed?
No. The page displays black and guides your observation. It cannot read panel luminance, quantify leakage or determine whether a device qualifies for replacement.
Does this test apply to OLED?
OLED does not use a separate LCD backlight. For uneven near-black areas or persistent shapes, use gray-field observation and interpret the display technology separately.