I was just being curious as I would like to learn the threading procedures for the most common projector/soundhead set-up so I could possibly get another projectionist job. Also, I would like to see loop size to determine if my loops are to big (Century C/CC).

If anyone has any, please send them to Brad.

Thanks Reg
 

It might be nice to have a seperate place where someone could view (and print) in html format. But with server space at a preminum, it might not make sense to sort of put the same info on twice.

Maybe copy the threading page from each manual, and save that alone as a pdf? Might make sense....
 

If anyone could take pictures of their thread-up and send it to the Brad so he can post it in the pictures section would help many of us new projectionists.

Thanks Reg
 

Have you looked at the other Century or Brenkert manuals? Maybe the threading diagram for those are shown, and are close enough to your projectors to use?

I have noticed that the documentation in projector manuals regarding use and threading have always been poor (well, except for a AA-II.) It's like they expect you to already know lots of other stuff.

But, you might try to figure it out yourself; now, I don't mean that rudely... I mean try to see exactly where the film has to go to run right.

For example, on any projector, we know that the optical sound is 18 frames ahead of the picture. So, get a length of scrap film, put a mark in the center of one frame. Count 18 frames ahead, and put a mark in the center of that frame. Then, thread the projector, placing one mark at the aperture and the other centered with the sound lens. For a little more accuracy, manually turn the motor over to place the shutter at the aperture during the "dwell" period before threading (where the shutter is blocking the light, but the intermittent is not pulling down the film.)

On some projectors like Centurys (I can't remember about Brenkerts) there's an intermediate drive sprocket in between the sound head and the intermittent. Now, you need to know what part of the film to put on that sprocket. You probably know that some projectors like Centurys usually require you to put (or pull) one sprocket hole of tension on the film as it goes around the impedence roller (sound drum.) So if you pull one sprocket hole up and lock it in, (or do what ever that particular sound head mfg. wants) the loop under the intermittent is now set.

If there isn't an intermediate drive sprocket between the sound head and the intermittent, (like a Cinemecannica or a Norelco) that part is done. It already is at the correct distance.

With the scrap film threaded like this, turn the framing knob about 1 full frame each way, (simulating correcting an out-of-frame) and advance the film a little each time. Verify it does not hit anything.

Do the same kind of thing for the loop above the gate. The film should have a gentle curve as it "exits" the feed sprocket, regardless of the framing knob's position. Of course, if you have a "before the gate" digital reader, the installer should have told you what that (reader to gate) distance is.

At a very long, narrow theater I worked at, we would advance the sound by a few sprocket holes, so people in the rear of the theater would hear the sound of an on-screen explosion at about the same time as it appeared. If we didn't, there would be a few millisecond delay.

Now, I don't know how much you know about projection, so I'm sorry if I said a bunch of stuff you already knew. But, this is what I show people if they are going to work at another theater, but don't know what equipment is there.
 

Regards to you all...

 

The Brenkert BX-100 manual has a threading diagram on page 12 (original manual page number, not the PDF page number).

The Century MSC-TA manual dated 4-93 has a threading diagram on page 9. This could be applied to any Century machine.

I don't want to sound stupid, but I couldn't find the Century MSC-TA manual on the manual page. It might be listed as a different manual. Thanks for the help and please clarify which exact manual it is.

Reg
 

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Dave Bird
 

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Dave Bird
 

18 frames? Your picture/sound synch is 150 feet from the screen. What size auditorium do you work at?

Dead synch is 21 frames plus or minus 1/2 frame. The projection leader sound frames are 20 frames away from their corresponding picture frames. That makes picture/sound synch about 50 feet away from the screen.
 

"The audio record on the film shall be displaced longitudinally from the center of the corresponding picture by a distance of 21 frames +/- 1/2 frame in the direction of travel during normal projection."

Annex A of that standard notes that the analog sound sync should be pulled up one frame for each 50 feet from the screen to the center of the seating area. For example, if the center of the audience is 50 feet from the screen, the projector should be threaded with 20 frames between the picture aperture and analog reader scanning point. This is because it takes about 1/24 second (one frame) for sound to travel 50 feet.

John Walsh must have quite a long auditorium if he normally threads with only 18 frames!

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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