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Topic: Projector question-Motiograph AAA

Erich Loepke
Film Handler

Posts: 43
From: Ft. Worth, TX, USA
Registered: Sep 1999

posted 12-12-1999 09:38 PM

Many thanks to all of you who took time to answer my questions. I'm new at this whole 35mm thing, so I really appreciate the information you gave. Since the topic switched to lamphouses, I have another question:

I'm guessing the best way to go is a Xenon lamp, probably about 450W or so. I don't imagine having a throw of more than 20-25 feet with a screen size between 5 and 10 feet, possibly. I'd be setting all this up once I move out of my parents' house, so I really don't know what my screening room will be yet. How much lamp power would work for my needs, and which model lamphouses are good or bad?

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

posted 12-12-1999 11:19 PM

Gee thats the forst machine that I serviced way back about 18 years ago. Interestingly,I service a theater in Burly,Idaho that has 5 Motiograph AA's and I just installed LED reverse scanners in the last two machines. Kelmar makes up a few of them now and then. If ya need one talk to Tom there and let him know you need one. The Motiographs produce the best projected image of all the theaters I service with the exception of theaters that have 70mm machines and run 35 on them. Those seem to have an edge. Basically, the Motiograph is an extremely good machine. The good points of the machine far outweigh the few problems that the drum shutter may give. One thing to oint out is that to be sure that yours has the indoor shutter. Alot were made with the Drive In shutter. Shutters are no longer available from Wolk.

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Aaron Sisemore
Flaming Ribs beat Reeses Peanut Butter Cups any day!

Posts: 3061
From: Rockwall TX USA
Registered: Sep 1999

posted 12-13-1999 12:20 AM

Tokiwa projectors also use a barrel shutter...
Aaron

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Bill Purdy
Expert Film Handler

Posts: 139
From: Seattle, WA
Registered: Oct 1999

posted 12-13-1999 11:17 AM

I think that you will enjoy your Motiograph. It is well suited for home theatre operation mostly for the reason Gordon mentioned above....it is extremely gentle with film and will run just about anything you put through it. To add to the barrel shutter comments, if you can find a carbon arc lamp, look at the curvature of the mirror and imagine the cone of light that it will produce and how far back from the aperture it will be. Now do the same thing for a Xenon lamp and I think that you will notice that it has a much shorter working distance. It is quite common for the barrel to mask off some of the light from newer designs of Xenon lamps because of this. Older Lumexes were a good compromise, but in any event, you don't really care since your use will be occasional and maximum efficiency isn't a problem. When I had a home theatre my screen size was 5 X 12 with a 23 ft. throw and I had a beautiful 16 FtL picture from an ORC M-1000 running a 750 Watt bulb at less than full power.

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Bill Purdy
Comonent Engineering

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Erich Loepke
Film Handler

Posts: 43
From: Ft. Worth, TX, USA
Registered: Sep 1999

posted 12-13-1999 01:29 PM

Hi guys-

I'm assuming 16 FtL is probably brighter than most theaters. Sounds like it wouldn't be too hard to achieve with the smaller screen size and short throw, though.

Also, how would I be able to tell the difference between a normal shutter and the drive-in shutter several of you mentioned?

Thanks once again, you've all been a great help!

-Erich

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John Pytlak
Film God

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

posted 12-13-1999 03:09 PM

A normal shutter completely blocks the light while the film frame is being pulled into position. For a normal 4:1 Geneva movement intermittent, this means the each shutter blade is about 90-degrees (360/4=90). A 5:1 high speed pulldown "drive-in" intermittent needed a shutter of about 72-degrees (360/5=72). The actual shutter blade angle required depends upon the cone angle of the lamphouse illumination, placement of the shutter in the beam, and amount of "play" in the gear-train. If the shutter is too small, travel ghost cannot be timed out. If the shutter angle is too large, you are wasting light.

"Drive-in" shutters basically cheated on the size of the shutter blade, using a smaller blade angle to get slightly more light. The rationale was that the travel ghost that resulted was not as visible at the typically low screen luminance found on huge drive-in screens. ANY visible travel ghost is unacceptable in a quality theatre.

Travel ghost is best seen in the closing titles of a film, when you have white letters against a black background. Ghosting (streaking) above OR below the letters can usually be eliminated by correct shutter timing. Ghosting on BOTH top and bottom of the letters usually indicates the shutter blades are too small or are damaged. If the ghosting varies, there may be excessive "play" in the gear train between the intermittent and shutter shaft.

------------------
John Pytlak, Senior Technical Specialist
Worldwide Technical Services, Professional Motion Imaging
Research Labs, Building 69, Room 7419
Eastman Kodak Company
Rochester, NY 14650-1922 USA
Tel: 716-477-5325 Fax: 716-722-7243

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Jon Miller
Jedi Master Film Handler

Posts: 973
From: San Diego, CA, USA
Registered: Sep 1999

posted 12-14-1999 08:17 PM

When I had this projector in service, I was using a Peerless Magnarc lamphouse running 7mm positives and 6mm negatives at about 48 A, to light a seven-foot-wide screen at a 16-foot throw. I got some flicker. Is it safe to say the system was over-lamped?

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Gordon McLeod
Film God

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

posted 12-15-1999 11:51 AM

The M1000 works well on the motiograph and so do most of the twin mirror verticle lamphouse (zies, and the zenieth 4000)
also the Kniseley Xenex1's that have the glass mirror they ahve a longer working distance vs it's F stop number
The Pup with a 750 watt would also work very well

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