Backlight zones
A locally dimmed LCD modulates groups of backlight emitters while liquid-crystal pixels shape the image. When one zone serves both a highlight and adjacent darkness, some light can remain visible beyond the requested object.
Inspect light spreading around dark-scene highlights
Screen Blooming Test
This blooming test places small rendered highlights against black. On an LCD or Mini LED display with zone-based local dimming, a bright object may activate a backlight area larger than the object and create a visible halo. Compare a square, circle, sparse points, subtitle-like bars, and a slow moving target without treating the result as a dimming-zone count or laboratory contrast measurement.
Keep one variable at a time
A repeatable blooming test workflow
- Use normal viewing distance and angle. Sit where you usually watch or work. A halo that looks large from a close, off-axis position may look different when centered. Reduce direct glare, but do not use an unrealistically dark room unless that is your use case.
- Begin with the isolated square. Use a moderate rendered signal and a small object. Look beside the edge rather than staring only at the bright center. Record whether a glow extends into the surrounding black and whether it is symmetric.
- Change object size before source level. A small highlight may engage a zone differently from a large one. Compare two or three sizes, then return to the original size before changing the rendered signal slider.
- Compare point and subtitle surrogates. Sparse highlights reveal interaction across separate positions. The generic horizontal bars approximate a bright caption layout without reproducing any copyrighted subtitle or video frame.
- Use slow motion for transitions. Watch whether the halo follows the target, lags, changes shape, or lifts the nearby black level. Pause on a suspect position and compare the static field before drawing a conclusion.
What changes the appearance
Four variables behind a visible halo
Algorithm priorities
Display processing may preserve highlight intensity, protect the dark background, or balance both. The chosen picture mode and local-dimming setting can change that tradeoff, but this webpage cannot alter the hardware setting.
Viewing position
LCD light leakage through nominally dark pixels can increase off-axis. Judge at your normal position first, then move deliberately to understand angle sensitivity rather than mixing angles within one comparison.
Camera rendering
Automatic exposure often brightens a mostly black frame and expands visible glare around a highlight. A photograph can document location, but it is not a neutral substitute for a direct observation or controlled photometric measurement.
Different light sources
Why OLED should not be interpreted like Mini LED
OLED is self-emissive at pixel level and does not use an LCD backlight zone behind the image. It can still show optical glare, reflections, camera bloom, panel processing, or visual adaptation around a bright object, but those observations do not establish the same local-dimming halo mechanism used by a Mini LED LCD.
If you want to examine how several highlights interact with zone control, use thelocal dimming test. It adds multiple moving objects, checkerboards, selectable star density, edge-to-center motion, and a static zone-stress arrangement rather than repeating this isolated-halo workflow.