Ghosting test. What follows the mark, and the setting that fixes it.
Ghosting is a trail behind a moving object: pixels that have not finished changing. Its opposite, a bright edge ahead, is overdrive pushed too far. This shows a mark moving at 960 pixels a second on a dark ground, asks what you see, and names the overdrive step to take.
This check is visual: it draws movement or flicker on the screen, and you judge the result by eye, so a screen reader cannot describe it. The list under "What it measures" says in words what each one shows. If motion or flicker makes you unwell, or you have reduced motion switched on, you can leave it out: no other test on this site depends on it.
One check
- Ghosting and overdrive
One check after another, with your progress along the top and a plain verdict on each. Nothing you show the camera or say into the microphone leaves this page.
In short
Ghosting test: the answer first
A ghosting test moves a mark across a dark ground and asks what you see at its edges: clean, a trail behind, a bright edge ahead, or both. Your answer names the overdrive step to try, because the eye is the instrument here.
Reading your result
- A trail behind
- Pixels have not finished changing. Raise overdrive one step and stop at the step before a bright edge appears.
- A bright edge ahead
- Inverse ghosting, overdrive pushed too far. Lower it one step; it is worse than the trail it was meant to cure.
- The sync track for a camera
- A camera panned with the mark photographs a clean ladder only at the right speed, the pursuit camera method, credited on the page.
What it measures
Measured here, not assumed.
- What you see
- Clean edges, a trail behind, a bright edge ahead, or both. The eye is the instrument, and the verdict says so.
- The setting
- A trail means raise overdrive one step; a bright edge means lower it one. The menu calls it Overdrive, Response Time, OD, AMA or Trace Free.
- The sync track
- A ladder of ticks under the mark, stepping each frame. A camera panned with the mark photographs a clean ladder only when it tracked at the right speed: the pursuit camera method of Mark Rejhon, used here with credit.
If it fails
The usual failures, and what fixes each.
- A trail behind
- Raise overdrive one step and run again. Stop at the step before a bright edge appears.
- A bright edge ahead
- Lower overdrive one step. Inverse ghosting is the setting too high, and it is worse than the trail it was meant to cure.
- Both
- Try the middle setting. Some panels cannot be clean at every rate; choose the one that is clean at the rate you use most.
Where a browser stops
What it cannot tell you.
- A page cannot measure pixel response. Reviewers put a photodiode on the panel for that; this shows what your eyes see and what to change.
- Persistence blur, an even smear on both edges, is not ghosting and no overdrive setting removes it; a higher refresh rate does.
- On a variable refresh rate panel, overshoot often appears only at lower frame rates. Test at the rate you play at.
Privacy
Nothing leaves this page.
The camera and microphone are read on this page and stopped as soon as they have been measured. The clip you can play back lives in the browser's memory and is discarded when you leave. The location check discards the position. The internet test sends random bytes to this site and nothing else. The result is stored nowhere unless you ask for it by email, and then only the fact that an email was sent is kept.
Questions
Ghosting test, answered
- What is ghosting on a monitor?
- A faint trail behind moving objects, from pixels that take longer to change than one frame lasts. It is a slow pixel response, and the overdrive setting is the cure, up to a point.
- What is inverse ghosting?
- A bright or dark halo ahead of a moving object. The pixels were driven so hard they overshot their target colour and had to come back. It means overdrive is set too high.
- Which overdrive setting should I use?
- The highest one that shows no bright edge on this test at the refresh rate you use. Usually the middle setting; the top setting overshoots on most panels.
- What is overdrive called in my monitor menu?
- Overdrive, Response Time, OD, AMA or Trace Free, depending on the maker. They all set how hard the pixels are pushed to change.
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