Monitor Ghosting Test
Watch the trailing edge of each square as it moves.
Ghosting is a faint trail left behind a moving object on screen, caused by pixels changing colour more slowly than the image moves. Inverse ghosting — a bright halo instead of a dark trail — is the opposite fault, caused by overdrive pushing pixels too hard.
How to use this test
- Set the background to grey — mid-grey transitions are where ghosting is most visible on most panels.
- Start at the default speed and watch the trailing edge of each moving square.
- Raise the speed until you can see a trail, then note roughly where that begins.
- Compare a dark square on light background with the light square on dark: overdrive faults usually show on one and not the other.
What your results mean
| What you see | What it means |
|---|---|
| A faint dark smear behind the object | Conventional ghosting. The pixel is still finishing its previous colour transition when the image has already moved on. |
| A bright halo or outline ahead of or behind the object | Inverse ghosting, also called overshoot. The panel's overdrive is pushing pixels past their target value and then correcting. |
| A clean edge at moderate speed, trailing only at very high speed | Normal. Every panel has a transition time; the question is whether it is visible at the speeds you actually use. |
| Heavy trailing even at low speed | Either a slow panel, or an overdrive setting that is disabled or set too low in your monitor's menu. |
Common problems and fixes
Trailing is worse than you expect
Check your monitor's overdrive setting — it is often called Response Time, Overdrive, TraceFree or AMA depending on the brand. The middle setting is usually the best compromise; the most aggressive setting typically introduces inverse ghosting.
You see a bright halo
Reduce overdrive by one step. Overshoot is almost always an overdrive setting that is too aggressive for the current refresh rate.
Ghosting appears only at low refresh rates
This is common with variable refresh rate displays, because a single overdrive tuning cannot suit every refresh rate. Some monitors offer variable overdrive to compensate.
You cannot tell whether what you see is ghosting
Pause the animation. A still image shows the object with no trail at all, which gives you the comparison your eye needs.
Why this matters
Ghosting is the difference between motion that looks crisp and motion that looks smeared, and it is not something a specification sheet reliably tells you. Advertised response times are measured under manufacturer-chosen conditions that rarely match how you use the display. Seeing the trail yourself, at the speeds you actually play or scroll at, is more informative than any number on the box.
Longer walkthrough: Monitor Ghosting Test — full guide.
Frequently Asked Questions
What is monitor ghosting?
Ghosting is a faint trail following a moving object, caused by pixels taking longer to change colour than the image takes to move. The slower the pixel transition relative to the motion, the longer the visible trail.
Is ghosting the same as motion blur?
Not quite. Ghosting is a panel limitation — pixels physically changing too slowly. Sample-and-hold blur is a property of how almost all modern displays present a static frame for the whole refresh interval, and your eye tracks across it. Both make motion look soft, but only ghosting is a panel fault.
What is inverse ghosting?
Inverse ghosting, or overshoot, is a bright halo around a moving object rather than a dark trail. It happens when the panel's overdrive circuit pushes a pixel past its target value to make it transition faster, then has to correct back. Reducing the overdrive setting usually removes it.
Can this test measure my monitor's response time in milliseconds?
No, and no browser test can. Measuring pixel transition time requires an optical instrument such as a photodiode or a high-speed camera pointed at the panel. This test shows you whether ghosting is visible to you at a given speed, which is a different and arguably more useful question.
Does a higher refresh rate reduce ghosting?
It reduces perceived blur because each frame is shown for less time, but it does not make the pixels themselves transition faster. A high refresh panel with slow pixels can still ghost badly. The two properties are independent.
Why does ghosting look worse on grey backgrounds?
Grey-to-grey transitions are the slowest on most LCD panels, because the liquid crystal has to settle at an intermediate position rather than swinging fully on or off. That is also why manufacturers quote grey-to-grey response times.
Sources: MDN — requestAnimationFrame() · MDN — performance.now()
Found an error on this page, or a result that does not match your hardware? Tell us and we will correct it.