This is topic 70mm projector speed in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.
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Posted by German Marin (Member # 918) on 09-08-2002, 05:12 PM:
There are not 70mm theatres currently working in my country, so I've never seen a 70mm film but I've seen a 7omm/35mm sprocket belong to a prevost. I've heard the speed of 70mm movie is 60 FPS. Is that true? If this is true, Is there a BIG difference between the quality of image?
Posted by Steve Kraus (Member # 476) on 09-08-2002, 05:34 PM:
No, they run at the normal 24 fps. The first film in Todd-AO, which is the original 65/70mm process of the format we are familiar with today, used 30 fps on the first couple of films before reverting to 24. While 65mm negatives can be used to generate very high quality 35mm 'Scope prints converting the frame rate never looks quite right so the first film, "Oklahoma!" was shot on separate takes in 35mm CinemaScope (24 fps) while the 2nd film, "Around the World in 80 Days" was shot in 65mm at both speeds enabling high quality 35mm reductions to be made of the 24 fps version.
Because the 70mm frame is about 25% taller (5 perf instead of 4) it does run at a faster linear speed even when at the same frame rate. At 24 fps it runs at 112.5 ft per min. as compared to 35mm's 90 fpm.
There was a 65/70mm process that ran at 60 fps called "Showscan" developed by special effects wizard Douglas Trumbull but it was only used in special venues, never on a feature, and is now all but dead.
By 65/70 we mean a 65mm camera negative (and intermediate) and 70mm print. The extra 5mm outside the sprocket holes on each edge made room for two of the magnetic stripes for 6-track sound. The frame dimensions are about 2.6 times larger than 35mm Scope (true anamorphic) and about 4.6 times larger than 35mm 1.85 and a similar comparison for the usable negative area of Super 35 which unfortunately is how the majority of Scope format films are made these days.
Image quality is roughly proportional to negative size so, yes, a true 70mm film can take your breath away with how good it looks. The increased frame rate of a film like "Oklahoma!" can also contribute to a gorgeous looking picture. I've seen Showscan and while it looked great I cannot say that it was that much better than 70mm @ 30 fps. to warrant the trouble.
Posted by Steve Guttag (Member # 268) on 09-08-2002, 05:41 PM:
_Brainstorm_ was a near miss on the Showscan process being used on a feature film but that was the only attempt I'm aware of.Steve
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"Old projectionists never die, they just changeover!"
Posted by Mark Gulbrandsen (Member # 72) on 09-08-2002, 07:06 PM:
Now back to German's question.
The Showscan process did run at 60 fps and was the only process to be bumped to that high speed. Douglas Trumbull did alot of research that involved psycological studies into frame rate and found the 60 fps speed to allow maximum input to the visual brain senses. This makes for extremely realistic images when projected properly. I've seen Showscan many times in Vegas and it usually looks really really good. I was told that the barf rate for Showscan films is quite high so that may be an indication of how realistic it is.
Mark @ Claco
Posted by Thomas Hauerslev (Member # 566) on 09-09-2002, 03:29 AM:
Hi German, the "Cine Olimpo" in Caracas once featured the DP70 70mm projector Whatever happened to that cinema and the machines?
Cheers, Thomas
www.in70mm.com
www.dp70.com
www.70mm.dk
Posted by William Hooper (Member # 71) on 09-10-2002, 01:09 AM:
I say do it like in the silent movie days, run 'em as fast as you can!
Get that audience in & out! Turn 'em over, get those admissions!
And let's get out of here at a decent hour so we can stop somewhere for a drink & a bite to eat!
Posted by German Marin (Member # 918) on 09-10-2002, 03:38 PM:
Hi Mr. Kraus, thanks for clear all my questions.
Thomas, I was very young (about 8 years old) when the Cine Olimpo was closed, I just went twice there to see "Harry and the Hendersons" and "Haws 3" that in 3D. The company what I work to has a place like a warehouse where all kind of old equipment is placed. My boss tell me there is a 70mm projector in that place, maybe is that DP70 used in el cine Olimpo, if I find the right place of the projector I'll e-mail to the web site to update the info.
Thank you Thomas, Mr. Guttag and Mr. Gulbrandsen for the info.