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This topic comprises 2 pages: 1 2
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Author
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Topic: Changing speed on FP-30D
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Stephen Furley
Film God
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Posts: 3059
From: Coulsdon, Croydon, England
Registered: May 2002
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posted 10-22-2015 10:26 AM
Had an email yesterday asking if we can run an eight minute silent short on 35 mm in December.
We have a pair of scrap aperture plates badly cut for some other format, and replaced years ago, so I could re-cut these. Would only need one machine done for this film. we have enough screen available that we could use the Academy lenses. Can't shift the lens axis; I'm still thinking about that one. The Cinema Museum run silent film on FP-20s, I can ask the projectionist there how he gets around this problem. Looked at the loops, and there's no scratching within the silent frame area. The film is on safety stock. BFI recommend 16-18 fps, so it sounds like it's an early one, I don't know the title yet. The motors are driven by a box marked Kinoton 8100. Above this, between the two relay boards, is a board with three buttons, white, black and red, which select 24, 25 and 30 f.p.s.
There's a large removable cover on the front of the 8100 unit, which reveals nothing interesting, and a small one behind which are a three digit seven segment display which normally displays twice the frame rate, so presumably the output frequency of the inverter, and four buttons, PRG, up arrow, down arrow and SH. If I press PRG the display changes to C50 and if I then press the arrow buttons this number changes, but not always in steps of 1, and the motor speed doesn't change. SH button doesn't seem to do anything obvious.
Given the inverter drive system I'm sure that it must be possible to reduce the speed of the motor somehow, but I can't work out how. Any ideas.
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Stephen Furley
Film God

Posts: 3059
From: Coulsdon, Croydon, England
Registered: May 2002
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posted 11-10-2015 05:55 AM
Steve,
I've found a manual for a slightly different, but similar model. It says that C50 shows the current output frequency, which does seem to be the case.
C39 shows 60 at the moment, so it looks like you are probably correct. If I can change this to 36 I should be able to get 18 fps on the button which is doing 30 fps at the moment.
Have cut a plate, slightly undersized so I can finish it to match the actual print.
If I loosen the bolts I can move the projector slightly to centre the image. The silent short is the only 35 mm film to be run that day, so that will be ok. Am using the right-hand projector, so this will reduce the keystoning, not increase it.
Fabian,
Yes, we will get some flicker. The BFI recommend 16-18 fps for this film, so we'll go for the higher figure. A two-flash shutter is not ideal, but we cannot change that. Our 35 mm picture is rather bright; if we wind down the lamp current a bit the flicker will be less noticeable. It's only for eight minutes, we can get away with it. I've seen silent film running with conventional two-bladed shutters in the past, and this shouldn't be any worse than that.
I don't actually know what the film is yet; I'll have to ask.
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