Film-Tech Forum ARCHIVE: Projection formats

This is topic Projection formats in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Giorgio Volpi (Member # 1182) on 05-25-2002, 04:15 PM:

How many formats do you use?
In Venezuela we use only two, flat: calculated for panoramic, and scope.
Anyone of you is using three formats?
What are the relation you use to calculate lenses?

Have a good projection,
Giorgio.

Posted by Michael Brown (Member # 890) on 05-25-2002, 04:50 PM:

Flat (1.85), Flat (1.66)rarely and Scope.

Posted by Pete Naples (Member # 761) on 05-25-2002, 07:32 PM:

The last cinema I ran shows in had *takes a deep breath* 2.39:1 CinemaScope, 1.85:1 Widescreen, 1.75:1 Widescreen, 1.66:1 Widescreen, 1.375:1 Academy, 1.33:1 Full Frame Silent.
Also hidden away in the downstairs lensboxes were 2.0:1 non anamorphic (why?!) and 2.5:1 'Scope, which if memory serves correctly was Cinemascope/4 track mag. That was a full kit, lenses, aperture plates, sprockets, and Westrex mag penthouse heads. From the days when Cinemascope was not set-up in all cinemas. In fact I recall seeing a field bulletin to Westrex engineers about modifications to the projector, required for Cinemascope. On very early Westrex 2001 projectors, they had to fit a different lens holder assembly (offset?), and the bulletin detailed filing large amounts of metal out of the front of the projector casting to allow for this!

Posted by Scott Norwood (Member # 30) on 05-25-2002, 10:14 PM:

In the US, a "well-equipped" booth will have four formats available: flat/1.33 (Academy, flat/1.66 (European widescreen), flat/1.85 (US widescreen), and scope/2.39 (anamorphic).

Unfortunately, many theatres are only equipped for the latter two formats....

Posted by Bobby Henderson (Member # 840) on 05-26-2002, 02:54 PM:

How many still have 70mm?

Posted by Steve Guttag (Member # 268) on 05-26-2002, 03:16 PM:

The bulk of my installations have:

1.37 Academy
1.66 Widescreen
1.85 Wider screen
2.39 Scope
1.33 16mm
1.33 Silent 35.

Silent though poses some issues in itself. I have found that since about 1916 the aperture is pretty uniform at around .680 x .910 inches (give or take a thousandth)...pre-1916 the aperture may be even taller. Some call it 1.25:1 even. I have one customer that I have termed one of their silent set of plates "Super-Silent" It is cut to .725 x .945.

For whatever reason, silent seems to have a bit of a following at the moment, most of my special venue theatres want the ability to play it and most often do.

Steve

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"Old projectionists never die, they just changeover!"

Posted by Frank Angel (Member # 248) on 05-27-2002, 01:04 AM:

Problem with Silent 1.33 and also CinemaScope mag-only prints is that the center-lines are shifted off center -- one might say that since they came first, the other formats are the ones that are off-center, but that's another post. They present a bit more of a problem than just cutting the correct lenses and aperture plates -- you need to do something about recentering the image;

In one of the first theatres I work in, the way they dealt with this issue was. a plate was attached to the floor at the rear foot of the pedestal. on the plate was an off-center cam that was machined with a handle. You moved the handle and the cam turned, pushing the rear of the pedestal just enough to move the image into the correct position. You moved the cam in the other direction, it pulled away from the pedestal and then you had to push the pedestal back into position for normal projection -- kinda crude, but it worked.

We deal with silent film programs from time to time. Lots of prints have been reprinted down to standard 1.37 sound aperture, but for the ones that are original silents, we need to reposition the projectors. Although we don't have a cam rig, we basically resolve the centerline thing in the same way -- I keep a crowbar in the booth and just move the backend of the pedestal over to a line marked on the floor.

As for mag-only prints, we've only come across a mag-only once -- SEVEN BRIDES FOR SEVEN BROTHERS. Unfortunately our CinemaScope screen didn't have the extra width that the 2.55 would have given us, so we had to loose the extra image width (cropped in the aperture plates), but we still had to reposition the centerline.

Frank

Posted by Steve Kraus (Member # 476) on 05-27-2002, 02:36 AM:

Re-centering can be taken care of via adjustable PC lens collars. Or, depending on the model, applying the 35/70mm lens shifter to your projector.

Posted by Pete Naples (Member # 761) on 05-27-2002, 02:49 AM:

The centring issue is why the Westrex guys of yesteryear had to file a great chunk out of the mech casting, where the lens holder pokes through. With that done, I think you then adjusted the lateral of the lens holder to get the lens centred to the aperture (optical sound) and when running silent or mag scope, one uses a eccentric lens sleeve. Obviously those are no longer available as Westrex is no more, but we have them made when required.

Posted by Steve Guttag (Member # 268) on 05-27-2002, 09:23 AM:

The recentering is not a big issue to overcome.

As Steve mentioned, there are the various PC-Cine adapters offered by ISCO and Schneider. Turreted machines can often accomodate the shift. Century single lens machines have an eccentric upper lens guide that can deal with it and there are other tricks.

Anytime you go above two formats, per projector, you are going to have centering issues. With just two, especially FLAT and Scope you can split the difference and no one will really notice. But beyond that and when you have desperite magnifications like between 1.85 and 1.37, you need to be able to move the lens about to keep the images centered.

Steve

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"Old projectionists never die, they just changeover!"

Posted by Manny Knowles (Member # 1171) on 06-21-2002, 07:32 PM:

I have new (larger) screens going in.

Am I correct in assuming that ideally, our masking should hit the "1.85" line and the "Anamorphic" line on the RP-40?

And what about the left/right edges? This is a fixed masking operation. Should the sides of the scope masking be guided by the arrows?

What is the likelihood that I will need to use a maximizer/minimizer in order to get perfect aspect ratios with BOTH lenses on fixed masking? Is there something I should bear in mind in order to achieve this goal with primes only?

Posted by Michael Coate (Member # 757) on 06-21-2002, 07:50 PM:

Steve Guttag said:

quote:
The bulk of my installations have:
1.37 Academy
1.66 Widescreen
1.85 Wider screen
2.39 Scope
1.33 16mm
1.33 Silent 35

What about 2.20:1 for 70mm?

Posted by John Pytlak (Member # 331) on 06-21-2002, 10:10 PM:

Manny asked:

"Am I correct in assuming that ideally, our masking should hit the "1.85" line and the "Anamorphic" line on the RP-40? "

Yes. The projectable area for 1.85:1 "flat" is 0.825 x 0.446 inches.

The projectable area for "scope" is 0.825 x 0.690 inches.

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John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Research Labs, Building 69, Room 7525A
Rochester, New York, 14650-1922 USA
Tel: +1 585 477 5325 Cell: +1 585 781 4036 Fax: +1 585 722 7243
e-mail: john.pytlak@kodak.com
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