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Topic: Shutters & Parts

Rory Burke
Expert Film Handler

Posts: 181
From: Burbank, CA, USA
Registered: Jun 2000

posted 09-29-2000 03:22 PM

John P <BOWS> <BOWS> <BOWS>

You are the film-tech guru I tell you. The screen size is 19.3 x 45.3 to be exact and with in you calculation's specs at that. Since that screen is THX it has a luminance of 16ft/Lamberts +/- 2ft/Lamberts.

Rory

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

posted 09-29-2000 06:20 PM

John,
On the several occasions I used high speed X-L's I noticed improved definition in all cases. That's one reason I installed them at the D.I. at Bass Lake Indiana. In all cases they utilized wider than normal shutter openings to achieve brighter on screen images which they did. You can observe how bright it can be right here on the Film-Tech picture page. Go to the Cinema Borealis pics and check out how bright the on screen "RAN" picture is compared to the Chicago skyline. This is a bright skyline and we had no trouble overcomming it with a high speed machine and 4kw lamp. This was my second use of a high speed machine.

Larry,
The CS-55 movement that I had was definately accelerated at least a little bit. If you rotate the machine over and look through the sight glass of yours you should be able to see that the cam pin is mounted in a sliding dovetail on the cam. This dovetail is operated by a roller bearing that rides on an inner cam behind the main cam. The other end of the dovetail also has a pin that sticks through the main cam. I don't think it was a very good H.S. design but what can one do with a Century movement in this department without a major re-design. This had to be very hard on acetate film even though Fox holes are stronger. It may also be a major reason that CS-55 was never accepted as a projectable format. I'd be curious to know if yours is the same.
Best,
MARK

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Steve Guttag
We forgot the crackers Gromit!!!

Posts: 12814
From: Annapolis, MD
Registered: Dec 1999

posted 09-29-2000 08:43 PM

John,

With traditional intermittents, you are correct about silent films and the need for more than two flashes per frame but with the new breed of electronic intermittents silent films can finally come into vogue! ;-)

Since the electronic intermittent's speed isn't dependent on the sprocket speed anymore, the shutter doesn't have to slow down either when projecting at slower speeds.

We just installed a pair of Kinoton FP-38ES (35/16mm) projectors at the National Gallery of Art in Washington DC. You can adjust these machines on the fly from 10fps - 30fps and the flicker doesn't change! They all look like 30fps with a double shutter! Since the intermittent is so quick, the light efficientcy is also outstanding. The other wicked thing about the electronic intermittent machines is the framing...you can roll the picture infinately (like an old TV with the vertical hold out of adjustment)...the loops never look like they change size!

Anyone considering showing silent films, really should check out a pair of electronic intermittent machines.

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"Old projectionists never die, they just changeover!"

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Gordon McLeod
Film God

Posts: 9532
From: Toronto Ontario Canada
Registered: Jun 99

posted 09-29-2000 08:45 PM

The phillips FP7 was thee first that was available with a high speed pulldown it was called the Super7
For telecine they used a special movement on the XL driven by its own selysen motor independent of the shutter.
The DI movement was not fast enough for telecine

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Gordon McLeod
Film God

Posts: 9532
From: Toronto Ontario Canada
Registered: Jun 99

posted 09-29-2000 08:53 PM

David get me the part numbers

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Tim Reed
Better Projection Pays

Posts: 5246
From: Northampton, PA
Registered: Sep 1999

posted 09-30-2000 06:32 PM

Simplex XL telecines also used a 3-bladed shutter, spinning at, I believe, 2160 rpm... and the intermittent's speed was geared to oscillate at a rythym which produced the requisite 3:2 pulldown rate.
It still worked out to be the same as a normal projector with a 720rpm, 5-bladed shutter an a 3:2 intermittent, but Simplex used a different approach.

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Better Projection Pays!

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John Pytlak
Film God

Posts: 9987
From: Rochester, NY 14650-1922
Registered: Jan 2000

posted 10-02-2000 01:23 PM

With the availability of very high speed pulldowns (either "drive-in" intermittents or electronic pulldown, moving from 48 interruptions per second (typical 2-blade shutter) to 72 interruptions per second is now a viable option for many theatres. It virtually eliminates flicker.

The strength and durability of today's polyester print film can better withstand the higher accelerations from these high speed movements, allowing theatres to take advantage of increased light efficiency.

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John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Eastman Kodak Company
Research Labs, Building 69, Room 7419
Rochester, New York, 14650-1922 USA
Tel: 716-477-5325 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com

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