Heh old_tv_nut,
"...progressive scan at 72 Hz would _eliminate_ judder on 24 fps film material. Well, it does not, although it is cleaner than the 12 Hz components you get with 3:2 pulldown and 60 Hz displays"
This does seem counter intuative doesn't it
Changing rates is just such a hard thing to do, but native CRT 24fps HD displays have so much flicker
That program you wrote to determine the judder sounds interesting.
"I always hesitate pointing out the 3:2 judder to people who have not really paid attention to it, because once you notice it, it's hard to ignore."
It also drives me nuts the way most broadcast TV is time compressed now with it's associated artifacts, but heh, if you can sell more commercial time per half hour, who cares
"By the way, film in theaters is shown with a double shutter so that the flicker rate goes up to 48 Hz."
That was such a cleaver method using a light cutter for reducing flicker in film, kind of like interlacing on television to reduce flicker, although interlacing has so many side effects.
"For some of the tests of HDTV scan formats for the FCC ACATS, we used a ShowScan film, which is shot at 60 frames/second and therefore shows no judder when televised at 60 fps progressive."
It's a shame that more film isn't overcranked, but few are willing to pay the price. Hopefully with the coming of HD more will be done in 720/60p. The sad part is the technology has progressed tremendously, but little can be said for the content
Hi Anthony,
Many of these industrial displays use light shutters or valves and do have a lot of visible flicker to them. One that comes to mind is a color Oscilloscope we have at work that is field sequential, and can be quite annoying as you look around at the front panel and see the three colors separate!
Darryl