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This topic comprises 2 pages: 1 2
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Topic: Query from Home Theater Forum re: proj speed / shutter timing
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William Hooper
Phenomenal Film Handler
Posts: 1879
From: Mobile, AL USA
Registered: Jun 99
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posted 04-12-2004 03:49 AM
To reinforce what JH said: you go into a booth, 99.9% of what you'll find is 24fps, 2 bladed shutter, not adjustable.
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From Ramsaye's _A Million & One Nights_ :
In 1895, the whole industry adopted Lumiere's (1894) 16 fps
Edison's Kinetoscope had previously been 48 fps
SMPE, 1925: 60 ft/min camera, 80 ft/min projector
Divide ft./min by 3.75 to get frames per second, that gives you 16 frames per second in the camera, 21.33 projector.
However, that's SMPE, & not the Real World:
"This rate is close to the average, and denotes the public's desire to have its picture drama injected under greater pressure with an increasing dose, bigger than life & one & a third times as fast. Theatre speeds of ninety to one hundred feet a minute are common.
[...]
"It is of interest to observe that a tachometer test of the rate of exposure used by the head cameraman of the Douglas Fairbanks studios in 1923 indicated a rate of twelve exposures per second for normal action. this would give a decided acceleration on the theatre screen, adding to the agility of the agile Fairbanks. Both Fairbanks & Charles Chaplin as masters of screen tempo are given to manuipulation of camera speeds."
David Shepard has some information about silent era camera & projection speeds at:
http://www.cinemaweb.com/silentfilm/bookshelf/#March1998
Also very useful is Brownlow's book _The Parade's Gone By_, which examines the very unstandardized & even incorrectly estimated speeds at which the pitchers were took & run.
http://www.cinemaweb.com/silentfilm/bookshelf/18_std21.htm
Is an example of speed non-concreteness is SMPE's 1928: 55 to 65 ft/min camera, 75 to 85 ft/min projector. That's 14.6 - 17.3 fps camera, 20 - 22.66 fps projector. But that's SMPE, & not the two *expected* things which governed speed: Notes in the cans, or the projectionists' estimation.
"According to Stanley Watkins, head engineer for Western Electric, he and his team checked with the Warner Theatre for the average speed of projection in 1926. They were told 'between eighty and ninety feet per minute' in the big theatres- between 20 and 24 fps- and around 26 fps in the smaller theatres. They settled on 90 feet a minute (24 fps) as a reasonable compromise for the Vitaphone process"
There was no expectation or application of universal, set projection speed; only instructions from the film maker, & otherwise the discretion of the operator, which in the
absence of factors like scheduling of shows varied by taste &
perception & was informed by professional judgment.
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As to what shutter goes on there:
The multi-blade shutter was the invention of Albert E. Smith in 1899 (Ramsaye).
Steve Kraus asks if it would be correct to show early silents with a 3-bladed shutter, mostly because what we've seen in junk rooms are old Simplexes with 2-blade bowties. The reason we see bowties is because they're from larger venues which needed the light. So you can run post-1899 silents with a 3-blade shutter & feel all period-correct. If you've got some VERY early stuff like the Lumieres' "Demolition of a Wall" or "Feeding the Baby", there could be some question as to whether if the intent is to show kindness to the viewers, perhaps you should gas them instead.
A 1910 Power's [sic] with 3 blade shutter, mostly installed in storefronts or portable!
A 1916 Motiograph with 3 blade shutter, still pre-movie-palace days:
By the time of the late 20s, we're up to big houses, 2 bladed shutters for light efficiency, Vitaphone, & the bowtie we all know:
There's a photo of the booth of the NYC Roxy here somewhere 2-bladed shutters, Vitaphone tables, they ran silents (Vitaphone just for shorts), big house, all possible light needed for screen.
[edit: here's the booth of the new Roxy]
And just because it seems appropriate, here's an aftermarket 1929 Pacent optical sound head:
The choice of a 2-blade or 3-blade shutter is not made just from flicker reduction, but from how much light you can afford to lose. A 3-blade shutter has less flicker, but less light efficiency - too much of a tradeoff in a big house.
I have two 16mm Pageants with the centrifugal shutter design that is 3-bladed at 16 fps & 2 bladed at 24 fps.
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Leo Enticknap
Film God
Posts: 7474
From: Loma Linda, CA
Registered: Jul 2000
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posted 04-13-2004 08:25 AM
IMHO, the bottom line is that theatres which routinely screen archival prints and rep programming are likely to be equipped to show all speeds from 16-30fps without any flicker, usually with a combination of a three-bladed shutter and an inverter fitted to the motor. If you're planning a new installation from scratch and factoring archive and rep into the spec, then the choice of projector is crucial. The characteristics I would look for are:
- A 'film friendly' transport path - i.e. as few sprockets and pressure points as possible, plus routine operation at low gate pressure
- A film path design which enables you to lace up the film bypassing the optical sound pickup altogether; tinted and/or toned prints in particular will leave horrid amounts of crud on the pad roller and scanning drum.
- Ability to swap two- and three-bladed shutters, and time them, quickly and easily.
- Inverters for all speeds from 16-25fps, ideally with a remote selector and display which is easily accessible.
- A take-up spool powered by a separate motor with adjustable speed and torque. One which pulls too hard on an empty spool or fails to wind a full one tightly enough can cause cinch marks, edge damage and all sorts of nasties. This is especially important with a combined 35mm/70mm machine, if you consider the difference in weight between a 400 foot 35mm reel on a split spool and a full 3,000 foot 70 reel on a massive, cast-iron spool.
- A three-lens turret; very useful if you're dealing with lots of different ratios in quick succession.
For me it would be a toss-up between a Vic 5 and an FPXX in most scenarios.
It's the temporary venues and occasional one-off festival screenings in, say, a multiplex that are the problem. As others have noted, these are likely to have no inverter (i.e. the projectors will only run at 24fps), a two-blade shutter to maximise light output and only have the plates and lenses for 1:1.85 and 'scope. Many venues will also have only one projector available, thereby requiring the print to be plattered: something which no archive approves of and many ban outright. The necessary extras to show silent prints at the correct speed and ratio can be installed very straightforwardly: it all boils down to money.
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Frank Angel
Film God
Posts: 5305
From: Brooklyn NY USA
Registered: Dec 1999
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posted 04-14-2004 08:03 AM
You also need to determine the precise nature of the cinema's expressed mission. What does it purport to be? Is this one of the many booths in a multiplex that plans to run some alternative titles some of which will be the occasional re-released silent? Or is it a commercial art house that may, on occasion, run a few silents or may even mount a series of silent titles which are taken from the available re-releases and restorations that are readily made accessible through regular distribution houses? On the other hand, are we talking about a theatre that is attached to a museum or housed in the Film Department complex of a major university which specializes in motion pictures of the silent era and who have their own archival print library of rare and original titles? The point being that to install a lot of expensive, very specialized equipment for the occasional silent film engagement of a title that is re-released by a studio, well this might be overkill. The reason being that those re-released titles, in all likelihood, will have been optically converted to sound format by randomly step-printing additional frames to bring it up to sound speed and also optically repositioned and resized to the standard sound format frame. This is done with many of the popular silent titles. These converted prints need no speed adjustments and no special plates or lenses nor does the image need to be recentered on the screen as would be the case for original silent prints.
Occasionally you will find some re-releases made where there is no conversion at all, they are simply direct copies onto new 35mm stock; in such cases, yes, you will need to vary speed and used silent aperture plates and shift the centerline on the screen, but even that might not require the installation of a variable speed motor. When we came upon such a contingency, we changed the gear pitch of the soundhead transmission gears to reduce the speed from 24 to 18 and it worked just fine. Flicker was a bit of a problem at first, but we cut back the light a bit and that seemed to be a viable fix; everyone was happy.
However, for really SERIOUS venues, like, say, MOMA or FILM ARCHIVES in NYC for example, which specialize in rare and often times original prints which they play regularly from their own vaults, such a venue would have to be designed with this in mind, making a serious commitment to a complete system that will properly play the silent format. This would including all the points detailed above, save one which I will add -- you will also have to build a nitrate certified booth, since if you are regularly running vintage prints rather than restored/sound converted prints, you certainly will encounter nitrate base material. All the speed controls and shutter adaptability will not help one nit if the booth is not constructed to meet all the safety and code requirements attendant to running nitrate prints.
Everthing depends on the overall mission of the cinema -- what does the cinema want to be.
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