WhitestScreen

Mini-LED Blooming Test

A free blooming test that shows bright shapes on pure black so you can spot local-dimming halos on mini-LED and micro-LED screens.

By , WhitestScreen.com

Pattern
Size

This mini-LED blooming test shows a bright shape against a black background, the classic setup for spotting the hazy halo that can appear around bright objects on mini-LED and micro-LED displays. Darken the room, go fullscreen, and look at the edges of the shape closely. It's free and works instantly in your browser, no download or account needed.

How to use it

  1. Darken the room as much as you can, since blooming is far easier to see with less ambient light.
  2. Tap Fullscreen, then try both the circle and the corner-boxes pattern.
  3. Adjust the size slider, since blooming is usually most visible with a small, isolated bright shape.
  4. Look closely at the edge of the shape. A soft gray or white glow extending noticeably into the black beyond the shape's actual border is blooming.
  5. Try Motion mode too. Some displays control a static bright shape well but show a trailing halo once it starts moving, since that tests how fast the dimming zones react, not just how much they bleed.

What you're looking for

Pass: a small halo tightly confined to the shape. That's normal and expected on any Mini-LED or FALD display.

Worth checking: a large, fuzzy, or distracting halo. Try lowering your monitor's Local Dimming setting from High to Medium in its on-screen menu. It often tightens halos at a small cost to black depth.

Frequently asked questions

What is blooming on a mini-LED display?
Blooming is a hazy halo of light that spreads from a bright object into the surrounding dark area. It happens because mini-LED and micro-LED displays dim the backlight in zones rather than pixel by pixel, so a bright zone containing a small bright object also lights up the darker pixels sharing that same zone.
Is blooming a defect I can return the display for?
Usually not on its own. Some amount of blooming is an inherent characteristic of zone-based local dimming technology, not a manufacturing defect, and its severity varies by how many dimming zones a display has. Check reviews of your specific model to see what's typical before assuming something is wrong.
Does OLED have this problem?
No. OLED panels light each pixel individually rather than in zones, so they don't produce blooming. This is one of OLED's key advantages over mini-LED for high-contrast content, traded off against OLED's own burn-in considerations.

Not sure this is your actual problem? Start with the full screen defect triage guide →

Cedrick Reese built this blooming test. It shows a white shape (a circle, corner blocks, or a moving shape) on pure black, because local-dimming halos are easiest to see around small bright objects on a dark field. The page can't measure blooming itself; it sets up the conditions so you can judge it by eye. The patterns are fixed in the page's code with no outside data behind them.

About the creator

WhitestScreen.com was founded by Cedrick Reese, a retired veteran and web developer who enjoys building free, user-friendly online tools that simplify everyday tasks. More about Cedrick Reese →