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Author
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Topic: Film Projection Speeds
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David Pannell
Phenomenal Film Handler
Posts: 1072
From: Horsham, West Sussex, UK
Registered: Nov 2004
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posted June 08, 2009 07:04 AM
I know I have raised this topic before, but I just felt like ruminating over it again in case anyone else has had any more definite thoughts on the subject than previously.
As a silent film enthusiast, as I know many other Forum members are, why oh why didn't the projector manufacturers build their machines with more than 2 speeds in the main?
As we know, silent films were not always shot at 16 or 18fps, and even a quick glance down the Google references to silent film speeds, it immediately becomes apparent that in fact very few films were shot at these speeds. Cues for the projectionists of yesteryear contained instructions for required speeds for various sections of a film, and even films with a number of reels had instructions for each reel to be run at a different speed. This could be 16, 18, 20, 22, 24 & even 25fps in those days, dependent upon the action being filmed and the result the producer/director wished to achieve in the theatre.
It is also highly questionable as to whether the camera man was physically able to maintain a constant speed with the hand-cranked cameras of those days.
Many of the early Std 8mm projectors did have variable speed, as did the 16mm machines, but more latterly it seems that there was only the choice of 2 speeds: 18 & 24fps.
On the more modern machines with synchronous motors, (constant speed determined by the mains frequency), this is achieved by employing either stepped pulleys on the motor and driven shafts, or a drive wheel engaging a rubber covered disc at different distances in from the circumference, where one can swap between the 2 speeds - but no more! It would have been simplicity itself, for example, to have had several steps on the pulleys, rather like a lathe etc. or to have several differing positions that the drive wheel could engage the rubber covered disc.
Again, some of the more modern machines do have recourse to speed adjustment, but this usually involves adjusting a pre-set potentiometer. This involves in most cases, removing the cover of the projector and tweaking the pot till the desired speed is obtained - not the most desirous or expedient thing to do during a film show.
I'm really talking about a simple and straight forward speed change mechanism.
On the older machines, using brush motors, variable speed was achieved by the use of a variable rheostat, a contact breaker governor arrangement, or a combination of both.
Thus with the older, and it has to be said, the more versatile projectors, one could experiment with one's silent films and choose the most appropriate speed for the screen action.
Alas - not so with the more modern machines! ![[Frown]](frown.gif)
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Dave.
Valves and celluloid - a great combination!
Early technology rules OK!
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David Pannell
Phenomenal Film Handler
Posts: 1072
From: Horsham, West Sussex, UK
Registered: Nov 2004
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posted June 08, 2009 11:44 AM
Claus,
Of course, you're absolutely right about those theatre managers, as well as the method for achieving the desired speed for a silent film. Personally, I usually screen the film several times at different speeds when I first receive it, and once having established the most appropriate average speed throughout, I then include the preferred projection speed on the film can.
Michael,
This is really the best subjective - and objective way of determining the best speed at which a silent film should be run. Of course, you need a variable speed projector in the first place to find this out, as well as to run the film in the future. I don't think there's any other way round this.
I consider myself very fortunate to have several projectors with variable speed for Standard/Regular 8 and 16mm, though I don't have one for Super 8. But then again, I don't have any Super 8 silents (apart from home movies I shot myself). If I did, there could well be a problem!!!!
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Dave.
Valves and celluloid - a great combination!
Early technology rules OK!
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