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Author Topic: 24 FPS vs 25 FPS projection in today's theaters Lionel Fouillen Expert Film Handler Posts: 230 From: Belgium Registered: Nov 2002 posted 01-05-2004 06:38 AM                     I'd like to know if you have an idea about the proportion of theaters today, that actually project films at 25 frames per second instead of 24.  |  IP: Logged Steve Kraus Film God Posts: 4094 From: Chicago, IL, USA Registered: May 2000 posted 01-05-2004 09:46 AM                    None that I am aware of save those who have electronic drive projectors set wrong or incorrect timing pulleys and somehow, inexplicably, don't know it, and those who have worn out multi-V (driven) pulleys resulting in a faster than standard speed (I went through that once upon a time). Which rounds out to essentially none.  |  IP: Logged Stephen Furley Film God Posts: 3059 From: Coulsdon, Croydon, England Registered: May 2002 posted 01-05-2004 10:35 AM                     Lionel, I'm not sure I understand the question; do you mean places that project all films at 25 fps, or places that can run at that speed, and therefore would do so If they received a film intended to be run at that speed, but run other films at 24? In London, the National Film Theatre can run at variable speeds from 16 (I think) to 30. ICA Cinema 1 can run at set speeds of 18, 24 and 25. Both places normally run at 24, and would only do otherwise when required. I don't know of any which normally run at 25. What about preview theatres in television production facilities in PAL areas, they may run at 25. Didn't the Philips FP-20s with pulsed lamps run at 25 on 50Hz. supply? I don't know of any still in use now.  |  IP: Logged Lionel Fouillen Expert Film Handler Posts: 230 From: Belgium Registered: Nov 2002 posted 01-05-2004 03:17 PM                     Stephen, I meant theaters purposedly showing all films at 25 FPS to slightly shorten the total projection time, therefore sparing the xenon lifetime, arguing that the difference between 24 and 25 is hardly noticeable, and arguing even more that "it's the way films are shown on TV anyway" (although all this seems unacceptable to me!)...  |  IP: Logged Paul Linfesty Phenomenal Film Handler Posts: 1383 From: Bakersfield, CA, USA Registered: Nov 1999 posted 01-05-2004 03:33 PM                     I always suspected the old AMC Stockdale 6 theatres in Bakersfield (1974-2000) did this. Every feature length film shown there seemed to get out a cuople of minutes short of the published running time.  |  IP: Logged Michael Schaffer "Where is the Boardwalk Hotel?" Posts: 4143 From: Boston, MA Registered: Apr 2002 posted 01-05-2004 04:33 PM                        Many Kinoton models have the option to run at 25fps. I know that a lot of people cannot resist the temptation, but in the chain I worked for in Germany, we made sure the projectors would always run at 24fps. Especially after one projectionist had set a machine to 25 to be able to go home earlier (as if those 3 minutes or so made a difference). The next day, we ran interlock and it led to an ugly accident. A lot of cinemas in Eastern Europe have the Meo 5XB projector. This will only run at 25 because that was the standard in the Eastern Block.  |  IP: Logged Chris Hipp Phenomenal Film Handler Posts: 1462 From: Mesquite, Tx (east of Dallas) Registered: Jul 2003 posted 01-05-2004 06:10 PM                     Is really worth the trouble to save about 6 minutes from a two hour movie?  |  IP: Logged Brian Guckian Jedi Master Film Handler Posts: 594 From: Dublin, Ireland Registered: Apr 2003 posted 01-05-2004 06:10 PM                     I hope the answer would be almost none. I think this has come up before - certainly projecting 24fps material at 25fps is unacceptable; the change in pitch in fact is noticeable to quite a lot of people for starters (which is corrected during TV transmission). Like Stephen said, the 25fps option is for screening prints of TV productions in specialised preview theatres. Nowadays I would imagine this doesn't happen much, as DigiBeta + DLP seems to have made huge inroads in this area. Where are those security covers!  |  IP: Logged Stephen Furley Film God Posts: 3059 From: Coulsdon, Croydon, England Registered: May 2002 posted 01-06-2004 05:43 AM                     Lionel, I don't know of anywhere doing this, which is not to say that there isn't anywhere doing it, of course.  |  IP: Logged Dick Vaughan Phenomenal Film Handler Posts: 1032 From: Bradford, West Yorkshire, UK Registered: Jul 2000 posted 01-06-2004 07:35 AM                        There was a small 4 screen near here that ran at 25fps but of course never advertised it. When asked by the discerning patron why the film was shorter there than at any other cinema in the area they used to tell them it was so the projectionist could catch the last bus home! They were also renowned for forgetting to swing the anamorph when changing from ads and trailers to a scope feature on a regular basis. Luckily the place is no more  |  IP: Logged Sam D. Chavez Film God Posts: 2153 From: Martinez, CA USA Registered: Aug 2003 posted 01-06-2004 09:58 PM                       The Ziegfeld Theatre in NY had Zeiss projectors that would not run anything but 25 FPS. This led to no end of trouble but they may still be there for all I know.  |  IP: Logged Lindsay Morris Expert Film Handler Posts: 233 From: Darlington, WA, Australia Registered: Sep 2002 posted 01-07-2004 02:20 AM                     It was quite common in AC (50hz) arc days to slightly increase the projector speed to avoid the strobing effect of the shutter and the AC arc pulsing. The most common way was to simply wind some plastic insulation tape onto the drive motor pulley (in the direction so it was always winding on when running.. so it stayed there) and thus bring the projector speed up enough so the strobing was not evident. Who knows exactly what the speed actually was but it was faster than 24fps and did not seem to alter the pitch of the soundtrack much that I could ever notice. There are a couple of AC arc private cinemas I know of that are using tape on the pulley and one owner intends to manufacture a couple of new pulleys so he does not have to worry about occasionally replacing the tape which slowly does wear down. The change in pitch was quite evident if you had only done one machine and ran film and then on the change there was a slight pitch shift. At one of the old cinemas where I worked years ago a rectifier failed during a show (each machine had it's own rectifier). The old RCA Arconomiser was dragged off the slide arc, hooked up to the failed machine, some tape wound onto the pulley... just how much was a big "guess", the negative carbon changed to a postive, the lamp lit up ready for change and over we went. This was all done in the 20 minutes the other machine was running. We ran all weekend like that with a quite pronounced pitch shift, up/down at each change but the show never stopped. During the week the failed rectifier was repaired but we forgot about the tape on the pulley until the first change... oops Lindsay  |  IP: Logged

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