If moving text smears, enemies leave a dark trail, or fast camera pans have a bright halo, the problem is usually described as ghosting. The visible trail may come from a slow pixel transition, aggressive overdrive, or normal persistence blur from a sample-and-hold display.
Run the monitor ghosting test on your own panel, using full screen where supported, then compare what changes with the monitor's overdrive setting.
Ghosting, inverse ghosting, and motion blur are different
Pixel response time is commonly described by grey-to-grey, or GtG. It is the time a pixel needs to move from one intermediate shade to another. If that transition takes longer than the time available for a frame, the old shade remains partly visible as the image moves. That creates the familiar soft, dark trailing smear behind a moving object.
Monitor makers use overdrive to speed those transitions up. It applies an extra voltage impulse to move liquid crystals toward their target faster. When it is tuned well, edges look cleaner. When it is too strong, the pixel can overshoot before settling. The result is inverse ghosting: a bright, high-contrast, or inverted-color halo behind the moving edge.
There is also motion blur from sample-and-hold persistence. Each frame remains visible until the next refresh. As your eyes track a moving object, they integrate those static frame positions. That can make motion look blurred even when the pixel transition itself is fast, especially at lower refresh rates.
| What the trail looks like | Likely cause |
|---|---|
| Soft dark smear behind the object | Slow pixel transition or conventional ghosting |
| Bright, pale, or inverted halo | Overdrive overshoot, also called inverse ghosting |
| General blur while objects move, without a distinct colored trail | Frame persistence and refresh-rate limits |
Run a repeatable ghosting test
Testing needs a consistent motion pattern. The ghosting test moves an object at a controlled speed using animation timing from requestAnimationFrame. It includes several backgrounds because a trail that is hard to see on one tone can be obvious on another.
Use this workflow:
- Set the monitor to its intended refresh rate in the operating system.
- Start with the monitor's default or middle overdrive setting.
- Open the ghosting test in full screen where supported and watch the leading and trailing edges at your normal viewing distance.
- Repeat at the available motion speeds and background tones.
- Change overdrive one step at a time, then rerun the same pattern.
Do not chase the most aggressive setting because it has the most impressive name. Stop when the dark trailing smear improves without introducing a bright halo. The best setting can differ at 60 Hz, 120 Hz, and the monitor's maximum refresh rate, because the frame time changes as refresh rate changes.
Why a "1 ms" label does not settle the question
A response-time number on a box does not describe every transition your panel makes. It may refer to a best-case measurement, a specific overdrive mode, or MPRT rather than grey-to-grey response. MPRT concerns how long an image persists on the retina, while GtG concerns how quickly the pixels change state.
Most importantly, a low MPRT figure does not add frames. A 60 Hz monitor still updates once every 16.67 milliseconds. Strobing can reduce the time each frame remains visible, but it does not turn a 60 Hz display into a higher-refresh display.
That is why visual testing matters. You are checking the interaction between the panel, its current overdrive setting, and the refresh mode you actually use, not just reading a single specification.
Pair the motion test with a browser refresh check
Run the refresh rate test before or after the motion test. It estimates the refresh cadence this browser receives, and reports frame time, jitter, and missed frames while showing a pattern that can make tearing visible.
The result is not a certification of the panel's advertised Hz. Browser timing can be constrained by a hidden or unfocused tab, battery-saving modes on mobile, privacy settings that reduce timer precision, or mixed-refresh multi-monitor setups. Use it to confirm the current browser session looks plausible, then verify your operating-system display setting if the result is unexpectedly limited.
When the test cannot tell you the cause
A browser test can expose an artifact but cannot inspect the monitor's internal overdrive table or measure its laboratory response-time curve. It also cannot measure PWM flicker in software: backlight modulation operates far above the sampling range of browser rendering and timing APIs.
If you are sensitive to flicker, use a physical method instead. At a dim brightness, a high-speed camera view can reveal moving dark bands from low-frequency PWM. A simple pencil test in front of a dim screen can also reveal a stroboscopic sequence rather than smooth motion.
Make the result actionable
After testing, keep the setting that produces the cleanest moving edge at the refresh rate you use most. If the monitor still shows obvious dark smearing at moderate overdrive, it may be a limitation of the panel's transitions. If every stronger mode produces a bright halo, leave overdrive below its maximum rather than trading one artifact for another.
For a new display, note your observations during the return window. For a used monitor, test before paying. The Screen & Monitor Test can take you through the wider inspection and export a local report, so a motion concern is recorded alongside any dead-pixel, uniformity, or banding findings.