Ghosting (also known as afterimage or trailing) is a phenomenon where fast-moving objects on a display leave behind blurred trails or double images. For gamers, video editors, and sports viewers, ghosting not only affects the visual experience but may also cause delays in operational judgment. However, many people don't realize that ghosting is not entirely equivalent to a monitor's "slow response time" — it is influenced by multiple factors including panel type, response time measurement methods, Overdrive settings, and observation techniques.

This article will provide a detailed introduction on how to scientifically observe ghosting using online ghosting test tools such as UFO Test, and explain the differences between GTG and MPRT in response time, helping you accurately assess your monitor's ghosting level and find reasonable optimization solutions.

1. What is a Ghosting Test? Why Test It?

A ghosting test evaluates a display's dynamic clarity by having fast-moving objects on screen move at a constant speed and observing whether their edges show blur, trailing, or afterimages. Unlike static image tests, ghosting tests more closely resemble motion picture performance in real-world usage scenarios.

  • Assess motion clarity: Whether the edges of fast-moving objects are sharp directly affects gaming and viewing experience.
  • Verify response time claims: Manufacturers' claimed 1ms or 2ms are often the best values under specific test conditions, and actual ghosting performance may vary significantly.
  • Optimize monitor settings: By comparing ghosting performance under different Overdrive levels, find the balance point between response speed and inverse ghosting.

2. UFO Test Online Ghosting Test Method

UFO Test is currently the most commonly used online ghosting test tool, requiring no installation — simply open it in a browser to test. Its core is a UFO icon moving rapidly horizontally against a background with evenly spaced vertical lines, making it easy to observe ghosting and blur levels.

  • Test environment preparation: Use the monitor's native resolution, disable browser zoom, and ensure the refresh rate is set to the highest supported value (such as 144Hz, 240Hz). Testing in a dimly lit environment yields more noticeable results.
  • Observe ghosting: Follow the UFO's movement with your eyes and observe whether afterimages or trails appear behind it. The shorter and fainter the ghosting, the better the dynamic clarity.
  • Observe background vertical lines: If the background vertical lines appear noticeably broken or blurred as the UFO passes, it indicates insufficient response time and the pixels cannot switch in time.
  • Compare different speeds: UFO Test offers different movement speed levels, with higher speeds more likely to expose ghosting issues. It is recommended to test from low to high speeds.

It should be noted that online tests are affected by browser rendering, system compositors, and capture devices, so results are for reference only. For precise measurements, a high-speed camera and dedicated test signals should be used.

3. The Difference Between GTG and MPRT Response Time

Response time in monitor specifications is typically measured in two ways: GTG (Gray to Gray) and MPRT (Moving Picture Response Time). The two have different meanings and cannot be directly compared.

  • GTG response time: Refers to the time required for a pixel to switch from one gray level to another, measured in milliseconds. The smaller the GTG value, the faster the liquid crystal transitions and the lighter the ghosting. However, GTG does not account for the effects of backlight scanning and visual persistence.
  • MPRT response time: Refers to the time a pixel remains visible in a moving image, typically reduced by inserting black frames or backlight strobing. The smaller the MPRT value, the clearer the dynamic image, but this may cause reduced brightness and flicker.

For average users, GTG is the basic metric; if pursuing ultimate dynamic clarity, consider monitors that support MPRT or black frame insertion technology. In actual use, response time values can only serve as a reference, and the final result still needs to be verified through ghosting tests.

4. Other Factors Affecting Ghosting and Optimization Suggestions

  • Panel type: TN panels have the fastest response time but poorer color and viewing angles; IPS panels offer good color but traditional IPS has slightly slower response time; OLED panels have extremely short response time with virtually no ghosting, but are more expensive.
  • Overdrive settings: Properly increasing Overdrive can accelerate liquid crystal transitions and reduce ghosting, but setting it too high will produce inverse ghosting (white or bright trailing). It is recommended to start testing from the middle level.
  • Refresh rate: Higher refresh rates can reduce motion blur and perceived ghosting, especially when paired with high frame rate content.
  • Video cables and interfaces: Use DP or HDMI cables that support sufficient bandwidth to avoid display anomalies caused by insufficient bandwidth.

5. Summary

Ghosting testing is an important method for evaluating a monitor's dynamic display capability, and UFO Test provides a simple and intuitive online testing solution. By observing the trailing behind the moving UFO and the blur of background vertical lines, combined with knowledge of GTG and MPRT response times, you can more accurately assess your monitor's ghosting level. When optimizing, it is recommended to first adjust the refresh rate and Overdrive settings, then consider switching to a monitor with a more advanced panel type. Remember, specifications are only a reference — actual experience is the ultimate standard.