Why do moving objects leave a trail on my screen?
If you're looking for keyboard ghosting — a key that drops out when you're holding several down — that's a different problem with its own page: see the keyboard ghosting and NKRO test. This page is about your monitor: a faint trail or smear behind anything that moves on screen.
Test your monitor right now
Watch the Ghosting pattern run live — moving blocks at three speeds make any trail or smearing obvious.
Run the live test →What is monitor ghosting?
Every LCD pixel takes a small but real amount of time to shift from one shade to the next — its response time, usually measured grey-to-grey (GtG) in milliseconds. If that transition takes longer than the gap between frames, the pixel is still partway through changing when the next frame arrives, so part of the old image blends into the new one. Follow a moving edge across the screen and that blend shows up as a trail. That's ghosting.
It's a distinct problem from motion blur in general. Even a display with an instant pixel response still blurs moving images somewhat, because it holds each frame steady on screen for the full frame interval instead of flashing it briefly — a side effect of how LCD and OLED panels display motion at all, not of the pixels themselves. Ghosting specifically is the part caused by slow pixel response, and it's the part this test isolates.
Ghosting, inverse ghosting, and correctly tuned overdrive
Monitors fight slow pixel response with overdrive — briefly overshooting the target voltage to force a faster transition. Getting the amount right matters:
- Too little overdrive — the classic dim trail behind a moving edge. The pixel simply hasn't finished changing yet.
- Too much overdrive — a bright or dark halo instead, called inverse ghosting. The pixel overshoots past the target shade before settling back.
- Correctly tuned — a clean edge with no trail and no halo, at whatever overdrive level the panel can actually sustain.
How to test for monitor ghosting
- Run the Ghosting pattern and follow the moving blocks with your eyes across all three speeds.
- Look for a trail versus a halo. A dim trail behind the block is ghosting; a bright or dark edge ahead of or behind it is inverse ghosting.
- If your monitor has an overdrive, response-time, or "OD" setting in its on-screen menu, adjust it one step at a time while the pattern runs, re-checking after each change.
- Check your refresh rate too. A higher refresh rate shrinks how far a trail can smear per frame even without changing the panel's response time — use the Refresh meter pattern if you're not sure what you're actually getting.
- If trailing persists at every setting, that's the panel's native response time, not a misconfiguration — common on budget VA panels, and not something a setting can fix.
Frequently asked questions
What is monitor ghosting?
Monitor ghosting is a faint trail or smear that follows a moving object on screen, caused by the panel's pixels changing colour slower than the image updates. It's most visible on fast-moving, high-contrast edges — a cursor, a game character, or scrolling text — against a plain background.
What causes monitor ghosting?
The panel's pixel response time — how long it takes a pixel to shift from one shade to the next — is the main cause. If that transition takes longer than the time between frames, the pixel is still partway through changing when the next frame arrives, so part of the old image blends into the new one. VA panels are typically slower at this than IPS or TN, especially on dark-to-dark transitions.
What's the difference between ghosting and inverse ghosting?
Ghosting is a dim trail behind a moving object, caused by pixels responding too slowly. Inverse ghosting is a bright or dark halo instead, caused by the opposite problem: the monitor's overdrive setting pushes the pixel transition too hard trying to speed it up, and it overshoots past the target colour before settling. Both show up on the same test pattern — a trail means turn overdrive up, a halo means turn it down.
Is monitor ghosting the same as keyboard ghosting?
No, they just share a name. Keyboard ghosting is when a keyboard's switch matrix fails to register a key you're holding down — a wiring limitation with nothing to do with displays. Monitor ghosting is a visual trail behind motion. If you meant the keyboard kind, the dedicated ghosting and NKRO test page covers that.
How do I test my monitor for ghosting?
Open the monitor tester and run the Ghosting pattern — it slides blocks across the screen at three speeds. Follow them with your eyes and look for a trail or smear behind each one. If your monitor has an overdrive or response-time setting, adjust it while the pattern runs and re-test after each change.
Can monitor ghosting be fixed?
Often, partially. Raising the overdrive or response-time setting in the monitor's on-screen menu speeds up pixel transitions, up to the point where it starts overshooting into inverse ghosting instead. A higher refresh rate also helps, since it shrinks how far a trail can smear per frame even without changing the panel's response time. Some of it is just the panel's native limit, though — budget VA panels in particular can't be tuned past their hardware response time.
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