How should I interpret the response times specified for an LCD monitor?
Autor: Andreas Roth
06/12/2005, 18:02 CET
The response time of the monitor is the amount of time it takes to switch from black to white (and back), which corresponds to a full contrast change. But full contrast changes are usually of no practical significance because they just don't occur that way in everyday use. If the process of turning on and off regarded separately, it is also called "rise" and "fall" time. It's irrelevant to make statements about whether the turn on time was more important than the turn off time. Both times should lie within acceptable boundaries since a practical display of content always needs both.
The rise and fall time of current devices does not exceed 40 milliseconds. The fastest response times to date are around 16 ms. Thus, moving mouse pointers or scrolling pages show little to no trails (ghosting). Video clips are usually free from these kinds of negative effects, too.
The smaller the "rise/ fall" value, the less blurring is seen in fast sequences of changing pictures. Around values of about 20 milliseconds and less alreasy allow for displaying fast paced action games in a way that is for the most part free of any ghosting. But due to subjectivity and individual perception it not possible to give clear and objective statement on whether this or that particular response time will be enough for quickly changing contents. In fact we rather want to encourage everybody to visually form his or her own opinion on this matter.
However, it should be noted that we made the practical experience that monitors using IPS panels with response times of 30 ms deliver better results than MVA panels with 25 ms. The response time can be optimized by increasing contrast or brightness values.
Basically, response times are measured using the colors black and white. Other color combinations can by all means show measurement results that are significantly worse. Hence, it is of much more practical importance to consider the gradient of the response time.