Screen Ghosting Test

What is this tool?

Ghosting is a faint copy of a moving object trailing behind it. It happens when pixels have not finished changing state before the next frame is drawn, so a little of the previous image is still on screen.

This test uses deliberately harsh colour pairs, because contrast is what makes a trail visible. White on Black, Black on White, Green on Black, Cyan on Black and Red on Black each stress a different set of pixel transitions.

The same speed ladder as the other motion tools applies — the trail that is invisible at 240 px/s is often unmistakable at 1920 px/s. You judge; the tool provides a controlled, repeatable stimulus.

How to use it

1. Choose a contrast patternStart with White on Black — it produces the most visible trail on most panels. Then try Black on White, which reveals the opposite transition, and the Green, Cyan and Red variants, which stress individual subpixel channels.
2. Pick a preset speedStandard · 960 px/s, Precision · 240 px/s, or Stress · 1920 px/s. Precision is best for confirming a faint trail; Stress is best for comparing two monitors.
3. Step through the speed ladder120, 240, 480, 960 and 1920 px/s. Note the first speed where a trail appears. That threshold is a repeatable characteristic of the panel and is far more useful than a yes-or-no answer.
4. Look behind and in front of the objectA trail behind the object is ordinary ghosting. A bright halo ahead of it is inverse ghosting from overdrive that has been pushed too hard. Which side the artefact appears on determines the fix.
5. Record the severityThe self-report options are No visible trailing, Slight, Moderate and Strong trailing. Pick one per pattern so you have a written comparison when you change an overdrive setting.

What the results mean

No visible trailing

At the speed and contrast you tested, pixel transitions are finishing quickly enough that nothing lingers. Retest at 1920 px/s before concluding the panel is clean — slow speeds hide a lot.

Slight trailing

A faint edge behind the object, visible if you look for it. This is normal on most LCDs and is not usually a fault. It is the baseline against which overdrive changes should be judged.

Moderate to strong trailing

A clear second image following the object. On a VA panel this is often worst on dark transitions — black smearing. Raising overdrive one step usually helps; raising it too far introduces the opposite artefact.

A bright halo ahead of the object

Inverse ghosting, also called overshoot. The panel is driving pixels past their target value to switch faster. The fix is to reduce overdrive, not increase it — which is why identifying the direction of the artefact matters.

Colour-specific trails

If Green on Black trails but White on Black does not, one channel's transition is slower than the others. That is a panel characteristic worth recording, and it explains why some content looks worse than the rest.

What it can detect

• Trailing behind moving objects at a known speed and contrast
• Inverse ghosting and overshoot from overdrive set too high
• Dark smearing, which shows most strongly on the black-background patterns
• Transitions that are slower on one colour channel than another
• Whether a change to the monitor's overdrive setting actually improved anything

Limits worth knowing

A browser can only report what the platform gives it. These are the honest boundaries of this page, so a result is never read as more than it is.

• The page carries a “Browser Test Limitations” section and its FAQ asks “Can a browser detect monitor response time?” It cannot. Response time is a physical pixel measurement taken with a photodiode or an oscilloscope; a browser can only present motion for you to look at.
• No millisecond figure is produced here, and none should be inferred. Severity is your observation — slight, moderate, strong — not a measured transition time.
• Browser frame delivery affects what you see. If motion is also uneven, check frame pacing before blaming the panel.
• Ambient light and brightness change how visible a faint trail is, so comparisons only hold if the conditions match.

Tips

• Change one thing at a time. Overdrive level, refresh rate and speed all move the result, so changing two at once tells you nothing.
• Note the speed threshold rather than a yes or no. “Clean to 480, slight at 960, moderate at 1920” is a description you can compare against another monitor.
• Use the same pattern each time you retest. Switching from White on Black to Green on Black changes the difficulty as well as the colour.

Troubleshooting

Related documentation

• DisplayMotion Blur TestMoving patterns at controlled speeds, so you can judge how sharp motion stays.
• DisplayDisplay Response Time TestControlled colour transitions for judging pixel response, trailing and overshoot by eye.
• DisplayRefresh Rate TestEstimate your display's refresh rate from frame timing, with a confidence level attached.
• DisplayScreen Tearing TestScrolling patterns at chosen frame rates, so a torn frame becomes obvious.
• DisplayDisplay FPS TestMeasure the frame rate your browser is actually delivering, with 1% lows and jitter.