Screen Problem Diagnosis Guide: What's Actually Wrong?
"Something looks off on my screen" can mean a lot of different things, and most of them get lumped together in casual conversation even though they're completely different problems with different causes, different fixes, and different odds of actually being a defect. This screen problem diagnosis guide is a starting point: read through what you're seeing below, find the closest match, then follow the link to the tool or guide that covers it properly.
This covers visual panel artifacts specifically, not general hardware problems like a completely blank screen, flickering tied to a graphics driver, or a loose display cable. Those have different causes entirely and are outside what this guide is for.
Before anything below, it's worth ruling out the most common false alarm: dust and fingerprints get mistaken for real defects constantly. See how to clean your screen safely first if you haven't already.
Find your symptom
A single spot stays black, no matter what color is on screen
That's a dead pixel. It doesn't light up at all, on any color. Confirm it with the Dead Pixel Test, cycling through all the swatches to make sure it's genuinely off in every color, not just hard to see against one background.
A single spot stays lit in one color, regardless of the background
That's a stuck pixel. Unlike a dead one, it's still receiving power, just showing the wrong color consistently. The Dead Pixel Test's repair mode can sometimes work these loose with rapid color cycling. It's not guaranteed, and it only works on stuck pixels, never on truly dead ones.
Light leaking in from the edges or corners on a black screen
This is either IPS glow or backlight bleed, and the way to tell them apart is a head-tilt test, not a photo. Open Black Screen Test, go fullscreen, then tilt your head or lean toward and away from the screen. If the bright area moves or fades with your angle, that's IPS glow, a normal characteristic of the panel technology. If it stays exactly where it is no matter how you look at it, that's backlight bleed, generally considered a manufacturing defect. See the full screen uniformity guide for the complete walkthrough.
A hazy halo or glow around bright objects on an otherwise dark screen
On a mini-LED or micro-LED display, this is blooming, light from a bright zone spilling into the dark zones around it. Some is normal on any local-dimming display. A large or distracting halo is worth checking with the Mini-LED Blooming Test, which also has a pass/fail guide and a settings tip that often tightens it up.
A faint ghost of an old image lingering on an OLED screen
That's the early stage of burn-in, image retention from a static element (a taskbar, a channel logo, a game HUD) sitting in one place too long. Modern OLED panels ship with pixel-shift and logo-dimming protections that make this much rarer than it used to be. The OLED burn-in guide covers what actually helps and what those built-in protections already do for you.
A spot on the screen that just doesn't respond to touch
That's a different category entirely, the display itself might look fine while an area simply doesn't register taps or drags. The Touch Screen Test's grid mode lights up every cell you touch, so any square that never lights up despite repeated taps is a candidate dead zone.
Any of the above, specifically near a foldable phone's hinge crease
The crease flexes every time the phone opens and closes, and that mechanical stress is exactly where foldable owners have most often reported defects. See the dedicated foldable phone dead pixel and crease test guide, which also explains how to tell a genuine defect apart from a normal crease shadow or light reflection.
New device? Check it now, not later
If you're testing any of this on a monitor, phone, or foldable that just arrived, the clock matters. Retailer return windows for a defective screen are often shorter than the full manufacturer warranty period, sometimes just the standard general return window with no special extension. Our new monitor defect checklist walks through the full sequence to run in the first ten minutes.
Frequently asked questions
How do I tell a dead pixel from a stuck pixel?
Is a little bit of glow or bleed on a black screen normal?
Start with the Dead Pixel Test →
This guide exists to point you toward the right diagnostic tool rather than diagnose the problem itself, since that's a call a page can't fully make for you. Each defect description is checked against the dedicated tool and article it links to, so the symptoms listed here match what those pages actually test for.
About the author
Ready Utilities was founded by Cedrick Reese, a retired veteran and web developer who enjoys building free, user-friendly online tools that simplify everyday tasks. Read more →