Dead & stuck pixels
Nine pure colors, edge to edge. A dead pixel stays black, a stuck one stays lit.
1 minGuide
Monitor Uniformity Test
Flat greys and white show clouding, dirty screen effect and tint. 100% in your browser - nothing is uploaded.
1 min5 patterns
Click the preview to run it full screen
Your display
Updates when you move the window to another screen- Resolution
- ---
- device px
- Pixel ratio
- ---
- devicePixelRatio
- Refresh rate
- ---
- measured in this browser
- Color gamut
- ---
- reported by the browser
- HDR
- ---
- standard range
- Orientation
- ---
- current
How to run the monitor uniformity test
01Warm it up
Give the monitor 10 to 15 minutes: uniformity changes as the panel heats.
02Step through the greys
Go through 5%, 10%, 25%, 50% and white with the arrow keys or a swipe.
03Turn on zones
The screen splits into nine areas. Compare each one with the center.
04Find blotches and tint
Clouds on 5% and 10%, tint and darker corners on 50% and white.
What to look for
- Cloudy, uneven patches on dark grey: clouding, common on edge-lit LCDs.
- Vertical bands or smudges on mid grey: dirty screen effect, most visible when the image pans.
- A pink, green or yellow tint in one part of the screen on white or 50% grey.
- Corners noticeably darker than the center: vignetting.
What counts as a defect
- A difference you notice in normal content (a sky, a web page, a game with dark scenes) is worth reporting.
- Small differences only visible on 5% grey in a dark room are normal for most LCDs.
- Uniformity is rarely perfect. Compare against reviews of the same model before you return it.
What to do next
- Mention the zone numbers in your report note: “zone 7 visibly darker” is clear to support staff.
- Some monitors have a uniformity compensation mode in the menu. It trades a little brightness for a more even picture.
- On OLED, a near-black band or tint also shows here; follow up with the burn-in test.
Other screen tests
Each one checks a different part of the panel. The guided check runs them all in order.
Banding & gradients
256 equal steps per ramp. A good panel shows them evenly, a weak one clumps them.
1 minGuide
Sharpness & geometry
One-pixel grids, checkerboards and circles expose scaling blur and bad geometry.
1 minGuide
Refresh rate & tearing
Measures the real frame rate in this browser and shows tearing on a moving bar.
30 sGuide
About the monitor uniformity test
A perfect panel shows a flat grey as one even surface. Real panels vary: darker corners, cloudy blotches, a band of different tint, or a dirty screen effect that looks like smudges when you pan. Flat greys make every one of them visible, and the zone grid helps you compare areas instead of guessing.
It is one of the tests in the Screen & Monitor Test, which also runs a guided check through every test and ends in an inspection reportfor a return or RMA. Every pattern is drawn on your screen's own pixel grid, 100% in your browser - no upload, no install, no account needed.
Frequently Asked Questions
Dirty screen effect (DSE) is uneven brightness that looks like smudges or vertical bands on a flat color, most visible when the whole image pans, as in sports or games. It comes from variations in the panel and its backlight.
Dark greys (5 to 10%) reveal clouding and near-black issues, mid grey (around 50%) shows dirty screen effect and tint shifts, and white shows vignetting. That is why the test steps through all of them.
Yes. Almost every LCD varies a little from the center to the corners. What matters is whether you notice it in everyday content, not whether a camera can find it on a 5% grey.
Safari on iPhone does not allow web pages to go truly full screen. The test fills the whole visible area and hides all controls instead; rotate to landscape, or add the page to your Home Screen, to get the most of the panel in view. iPad and Android support real full screen.
No. Every pattern is drawn locally in your browser, and the inspection report is built and downloaded on your device. Nothing about your screen or your results leaves the browser, and no account is needed.
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