No power. Black on every colour including white. Not fixable.
Screen Bleeding Test
Panel check
Find the flaws in your screen
Flat colours, fullscreen, nothing else on the panel. Backlight bleed, dead pixels and dust are invisible on a normal page and obvious against one unbroken colour.
- Ten flat test colours
- True fullscreen
- Slideshow mode
- Tells you what to look for
Colour field
Go fullscreen, then click or press the arrow keys to change colour
Click to change colour · Esc to exit
Do it in a dark room with the brightness up. A lamp behind the monitor hides exactly the thing you are trying to see.
How to use it
How do I test for backlight bleed?
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1
Turn the lights off
Bleed is light escaping where it should not, and you cannot see it in a lit room. Give your eyes a minute to adjust.
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2
Go fullscreen on black
Press F. Browser chrome and a bright desktop behind the window both wash out the corners, which is where the problem usually is.
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3
Step through the colours
Click anywhere or use the arrow keys. Black finds bleed, white finds dust, and the solid colours find dead or stuck pixels.
What is backlight bleeding?
Light from the backlight escaping around the edge of the panel instead of passing through it. On a black screen it looks like a patch or streak of grey light creeping in from a corner. Almost every LCD has some — the question is whether yours has enough to notice while you are actually using it.
Is it bleed or IPS glow?
These get mixed up constantly, and only one of them is a defect.
The head test settles it. Lean left, lean right, move closer. If the glow moves with you it is IPS glow; if it stays exactly where it is, it is bleed.
Backlight bleed
Bright patches at the edges. Stays put when you move. A manufacturing flaw, and a valid reason to return a panel.
IPS glow
A silvery haze in the corners that changes as you move your head. Inherent to IPS. No return will fix it.
Dead pixel, stuck pixel or dust?
Three things that look alike, told apart by which colours they appear on.
A subpixel jammed on. A bright red, green or blue dot on black. Sometimes fixable.
A dark speck on white that does not change with colour, often fuzzy. Not a pixel.
How many dead pixels count as faulty?
Fewer than you would like. Most consumer monitors are sold to ISO 9241-307 Class II, which permits a couple of dead pixels and a handful of stuck subpixels before the panel counts as defective. Which is why "I have one dead pixel" often gets a polite refusal.
- Check the seller, not just the maker. Retailer return windows are often better than the warranty, with no pixel policy attached.
- Test on day one. Return windows are short. Run this the day the box is opened.
- Photograph it. A photo of a black screen in a dark room with the exposure locked is far more convincing than a description.
Does OLED get backlight bleed?
No — there is no backlight, so black really is off. What OLEDs get instead is burn-in: a faint permanent ghost of something static, like a taskbar or a game HUD. That is what the grey and white screens are for.
FAQ
Common questions
How do I test my screen for backlight bleeding?
Lights off, black colour, fullscreen. Look at the corners and edges for patches of light, and give your eyes half a minute to adjust first.
Is some backlight bleed normal?
Yes. Nearly every LCD has a little, and a small amount visible only on full black in a dark room is within tolerance. It is a problem when you see it during normal use.
What is the difference between bleed and IPS glow?
Move your head. IPS glow shifts or vanishes with viewing angle and is inherent to the panel type. Bleed stays exactly where it is, and is a defect.
Can this fix a stuck pixel?
Occasionally. Running the slideshow rapidly over a stuck subpixel sometimes unsticks it — leave it going for twenty minutes. A truly dead pixel cannot be revived.
Does it work on a phone?
Yes. Most phones are OLED, so look for burn-in on the grey screen and uneven patches on white rather than backlight bleed, which OLED cannot have.
Should I return a monitor with backlight bleed?
If you can see it during normal use, yes — and do it inside the retailer's return window rather than through a warranty claim.
Keep going
More tools
Everything here runs in your browser, free, with no sign-up.
Check your panel properly
Lights off, fullscreen, start on black. Two minutes before the return window closes.
Start the bleed test