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On refresh rate, and I’m only posting this because Feldon asked:
When speaking of refresh rate, there is a LOT more to consider than the “retrace rate. We have to first separate Refresh from Frame Rate. Also, this is VERY brief, but will give you the idea. Here are some fun facts, and then we will put them together.
Most Disney movies are animated on twos, which means 12 frames per second.
Anime is 8 fps.
NTSC is 29.97, double field.
RGB monitors are in the 75 to 160 herz (cycles).
Ok, what does all this mean? Let’s start with Disney. Disney uses 12 because this is the very least “change per second” or frame rate acceptable to them. It is also exactly half of the rate of film, which is 24 fps. Why was 24 chosen? Long story. But basically, it looks good enough vs. cost of film.
Video uses something close to 30 fps, and when movies which are 24 fps are shown on DVD or Video, they hold 6 of those frames a little longer. This is not noticeable to most people (although it still bothers me).
The big issue for both computers and monitors (like TVs) is the decay rate of the phosphors. In the case of TV, what they learned was that by the time the image was done rendering from the top to the bottom, the top was going dark. Thus, each new image made it look like it was flickering. To combat this, they doubled the trace time to about 60 (fields per second, not frames). So each image is rendered twice, but at half the resolution. This makes it look better. In Europe, they use\ the same bandwidth, but instead do 50 fps, and have higher resolution. So stuff looks better, but flickers more.
A comparison can be made of Anime, the Japanese prefer better looking images, and are willing to accept fewer of them (only 8 per second). Keep in mind, when it comes to cartoons, the “bandwidth” is number of lines drawn by a human per day.
Now to LCDs. They have a very long persistence (decay rate). So you basically can stick an image on them, and even if you stop rendering the image, it still looks bright. The down side is that images often smear, and fast colour changes suck.
As to what humans can see, this is a complex question. But 70 fps does seem to be the high end before no notable difference can be perceived.
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