Monitor Clouding Test

Press Full Screen on solid black in a dark room and let your eyes adjust. Diffuse, patchy bright zones in the middle of the panel are clouding — this test helps you tell it from edge bleed and judge whether it’s bad enough to return.

New to this? Here’s the plain-English version.

What this test is

A solid black screen that reveals cloudy, patchy bright zones in the middle of the panel — an uneven-backlight problem.

How it helps you

It helps you judge whether the blotchy glow you notice in dark scenes is mild and normal, or bad enough to return.

What we’re checking

Whether the backlight leaks unevenly into diffuse bright patches across the screen (clouding), as opposed to edge bleed.

Look for brighter, "cloudy" or "blotchy" patches.

Best viewed in a dark room with high monitor brightness.

In a dark room, turn up your monitor's brightness. Look for any large, faint patches that appear brighter than the rest of the screen. This is known as clouding or mura.

Press F11 or Full Screen · ← → patterns · Esc to exit

What Clouding Is

Clouding is uneven, patchy bright zones across a dark screen — most visible on solid black. It’s caused by the LCD backlight leaking through unevenly, creating a cloud-like blotchy pattern. It’s most common on VA panels, which have excellent on-axis contrast but are prone to it, particularly in the early weeks of use.

How to Use the Test

1Darken the room. Clouding is invisible in daylight — close blinds and dim the lights before testing.
2Go fullscreen on black. Press Full Screen on the pure-black pattern.
3Let your eyes adjust. Wait 10–15 seconds for your vision to adapt to the dark screen.
4Look for patches away from the edges. Edge brightness is backlight bleed; diffuse bright patches in the middle are clouding. Note whether they stay put or shift.

Clouding vs Backlight Bleed

Clouding

Diffuse, blotchy bright patches spread across the middle of the screen, from uneven backlight through the diffuser. Most common on VA.

Backlight bleed

Bright light at the edges and corners, from the backlight escaping the frame. Covered by the backlight bleed test.

Clouding Severity Guide

Appearance	Assessment
Uniform black, only faint edge glow	Normal — no clouding present
1–2 faint patches, invisible in content	Mild — acceptable for most use
Multiple visible patches on black	Moderate — distracting in dark scenes
Heavy patchy brightness across screen	Severe — return or replace if under warranty

Does Clouding Go Away?

Mild clouding on VA panels often reduces over the first 100–200 hours as the panel and frame settle. Gently pressing a cloudy area with a microfibre cloth (never hard, never with bare fingers) can temporarily redistribute diffuser pressure. Clouding that appears suddenly on an older panel, or worsens over time, points to diffuser-layer damage and won’t self-resolve.

Since clouding lifts your black level, it also affects perceived contrast — pair this with the contrast test and the broader uniformity test for the full picture before deciding on a return.

Clouding FAQ

Is clouding the same as backlight bleed?+

No. Backlight bleed is bright light escaping the panel’s edges and corners. Clouding is a diffuse, blotchy brightness pattern in the middle of the screen from uneven backlight distribution through the diffuser layer. Bleed is an edge problem; clouding is a whole-panel one.

Which panels get clouding?+

VA panels are most affected — they have excellent on-axis contrast but are prone to clouding, especially in the first weeks of use. TN and IPS show more edge bleed than clouding. OLED cannot cloud because each pixel is self-emissive, so there’s no backlight to distribute unevenly.

Can I fix monitor clouding?+

Mild cases often improve over the first 100–200 hours as the panel and frame settle. Gently pressing a cloudy area with a microfibre cloth (never hard, never bare fingers) can temporarily redistribute diffuser pressure. Severe clouding can’t be fixed without disassembly — if you’re within the return window, treat it as a valid defect.

Does clouding go away on its own?+

Often, partially, on new VA panels — settling over the first hundred-plus hours reduces mild clouding. Clouding that appears suddenly on an older panel, or worsens over time, suggests diffuser-layer damage and will not self-resolve.

Is some clouding normal?+

Yes. A uniform black with only faint edge glow, or one or two faint patches invisible during actual content, is within normal tolerance. Multiple patches clearly visible in dark scenes, or heavy patchy brightness across the screen, is where it becomes return-worthy.

Why can’t I see clouding during the day?+

Clouding is only visible on a dark screen in a dark room. Ambient light lifts the apparent black level and hides the patches entirely, which is also why clouding that only shows in a pitch-dark room during a black test pattern rarely matters in real use.

Should I return a monitor for clouding?+

Base it on real-world impact, not the test pattern alone. If clouding is obvious during dark movie scenes or game environments at your normal brightness, document it with photos and start a return within the retailer’s window. If it only appears on a pure-black screen in a blacked-out room, it’s usually within tolerance.

Related Monitor Tests

Backlight Bleed Test

Edge and corner light leak (the edge version)

Uniformity Test

Grey and white evenness across the panel

Contrast Test

Black-level depth and contrast ratio

Checking a whole new panel?

Run the dead pixel test and browse the full monitor test suite.

Monitor Pixel Test All Monitor Tests