Film-Tech Cinema Systems
Film-Tech Forum


Post New Topic  Post A Reply
my profile | my password | register | search | faq & rules | forum home
  next oldest topic   next newest topic
» Film-Tech Forum   » Operations   » Film Handlers' Forum   » Correct size of Vic 5 lower loop.

   
Author Topic: Correct size of Vic 5 lower loop.
Jonathan Wood
Expert Film Handler

Posts: 185
From: Oxfordshire, United kingdom
Registered: Jan 2008


 - posted 11-30-2016 11:50 AM      Profile for Jonathan Wood   Email Jonathan Wood   Send New Private Message       Edit/Delete Post 
I was just wondering if anyone out there still remember s the correct size of the lower intermittent loop on a Vic 5 and how best to set it ? I've always thought it was roughly a 'fingers worth ' !

Jon

 |  IP: Logged

Monte L Fullmer
Film God

Posts: 8161
From: Nampa, Idaho, USA
Registered: Nov 2004


 - posted 11-30-2016 02:11 PM      Profile for Monte L Fullmer   Email Monte L Fullmer   Send New Private Message       Edit/Delete Post 
Lacing up Cine machines are a breeze.

Thread the unit up with the film wrapped around the intermittent sprocket.

on the large lower holdback sprocket, pull film snug, then back off four sprocket holes, then close the pad roller down.

This will automatically made the correct lower loop size.

Good luck - Monte

 |  IP: Logged

Jonathan Wood
Expert Film Handler

Posts: 185
From: Oxfordshire, United kingdom
Registered: Jan 2008


 - posted 11-30-2016 03:22 PM      Profile for Jonathan Wood   Email Jonathan Wood   Send New Private Message       Edit/Delete Post 
Thanks Monte, a finger width sounds like it might be a bit much then . I'll give ur method a go.
Jon

 |  IP: Logged

Mike Schulz
Expert Film Handler

Posts: 119
From: Los Angeles, CA
Registered: May 2007


 - posted 11-30-2016 05:24 PM      Profile for Mike Schulz   Email Mike Schulz   Send New Private Message       Edit/Delete Post 
I used to run those Vic 5's years ago when I worked for GCC. From what I remember and unless you have huge hands/fingers, you should be able to get your pinky finger comfortably in the bottom loop or the tip of your index finger. My rule of thumb when threading any film projector is that after you thread it and start running it down a bit and it looks wrong, it probably is. If you've got a bottom loop flopping around and going crazy and kind of looks too big, then you should make it a little smaller.

 |  IP: Logged

Jim Cassedy
Phenomenal Film Handler

Posts: 1511
From: San Francisco, CA
Registered: Dec 2006


 - posted 11-30-2016 08:12 PM      Profile for Jim Cassedy   Email Jim Cassedy   Send New Private Message       Edit/Delete Post 
When I first encountered a Vic5 (or any machine you're not sure of loop size) the easiest
thing was to simply take a piece of scrap film & mark two frames 21frms apart. Put one
in the gate, and thread so the other winds up where it should be in the sound reader.
That will give you the size of the loop you need, and you can use your own 'finger-gauge'
or whatever helps you to form future loops of the correct size.

As they say in North Korea; "It's not rocket science"

 |  IP: Logged

Leo Enticknap
Film God

Posts: 6631
From: Loma Linda, CA
Registered: Jul 2000


 - posted 11-30-2016 09:25 PM      Profile for Leo Enticknap   Author's Homepage   Email Leo Enticknap   Send New Private Message       Edit/Delete Post 
Or just take a print with an Academy leader, and thread it with the start mark in the gate and the diamond three frames behind 11 between the photocell and exciter (or LED).

Of course, that assumes that the optical audio reader and all the rollers and other film path components between it and the gate have been correctly installed, which, if the projector has been modified since it left the factory (e.g. the original audio reader removed and a red LED one installed in its place), is not necessarily a safe assumption to make. But it all the projector components are OEM and the intermittent loop size looks OK, the chances are that you're good to go.

 |  IP: Logged

Sam D. Chavez
Phenomenal Film Handler

Posts: 1977
From: Martinez, CA USA
Registered: Aug 2003


 - posted 11-30-2016 10:03 PM      Profile for Sam D. Chavez   Author's Homepage     Send New Private Message       Edit/Delete Post 
I think I recall the DP70 was built a bit out of sync. There, I said it. I guess the thought was it was made for really large cinemas so it was done on purpose so it would be in sync toward the back of the house. I've never checked it myself.

 |  IP: Logged

Leo Enticknap
Film God

Posts: 6631
From: Loma Linda, CA
Registered: Jul 2000


 - posted 11-30-2016 11:07 PM      Profile for Leo Enticknap   Author's Homepage   Email Leo Enticknap   Send New Private Message       Edit/Delete Post 
With the OEM Philips head, I agree that the intermittent loop does look smaller than comfortable with the offset threaded correctly. With the Kinoton LED replacement installed, though, it looks about right to me.

And of course, Sam raises a valuable point: in a larger house, the sync is never going to appear perfect from everywhere. You can only aim to get it bang on from a point about half way between the back wall and the screen. If you're sitting right at the front or right at the back and looking at lip movements carefully, it is going to seem very slightly off. Apart from increasing the speed of sound, there isn't much you can do about that!

 |  IP: Logged

Simon Wyss
Film Handler

Posts: 70
From: Basel, BS, Switzerland
Registered: Apr 2011


 - posted 12-01-2016 04:44 AM      Profile for Simon Wyss   Email Simon Wyss   Send New Private Message       Edit/Delete Post 
Interesting answers and I think Leo grasps it closest.

As a professional projectionist responsible to my employer (if not entrepreneur myself), the producer, and the audience I want to be able to guarantee synchronism in one of the seating rows of the hall. We used to call it the pistol row because there you would have perfect synch impression of pistol shots seen mid-screen with an American framing, wich is actors cut off above knee.

The standards provide 20 frames spacing between the optical axis and sound pick-up while the sound advance on prints is specified 21 frames ± a half. With the original head leaders one would find a 1000-Hertz beep of one frame length on the sound track corresponding to two seconds before content. Upon verifying one would count exactly 84 hole pairs, one or two more or one or two less. Everything else is out of standard and rejectable.

For correct reproduction I need to know the actual sound advance of each roll of a print. With this information I can scribble a cue note that I paste to the front wall between the projectors. Then I thread up each roll according to the print’s advances. The AMPAS technicians underlied a 100-foot throw theater with about 90 feet of hall length. The one frame difference between sound displacement on the print and the distance with the projectors causes dead synchronism at 1/24th of a second of sound travel in air at 20 degrees Celsius, which is 343 meters per second, thus 14,3 meters from the speakers.

Assuming at least one foot of distance between the screen and the speaker membranes behind it I care for a seat row at 14 meters away from the screen. Spectators closer and farther from the speakers will still have an acceptable impression of the show, although not strictly perfect. The discussion is perhaps ridiculous but at the same time about 85 years old.

 |  IP: Logged

Louis Bornwasser
Film God

Posts: 4401
From: prospect ky usa
Registered: Mar 2005


 - posted 12-01-2016 05:48 AM      Profile for Louis Bornwasser   Author's Homepage   Email Louis Bornwasser   Send New Private Message       Edit/Delete Post 
FYI: "best" seat has always been 1.5 times the screen width. Format is not relevant. (tested by Fox during the Scope research,)

 |  IP: Logged

Brad Miller
Administrator

Posts: 17590
From: Plano, TX (36.2 miles NW of Rockwall)
Registered: May 99


 - posted 12-01-2016 10:45 AM      Profile for Brad Miller   Author's Homepage   Email Brad Miller       Edit/Delete Post 
Something to keep in mind is that we are still at the mercy of the lab on achieving "perfect sync". I can't tell you how many times over the years I was assembling prints with unique sound waves around the last several or first several frames of a reel. When joining them together without removing an ID frame, I've seen the sound waves only line up if I was to intentionally go in and remove 1-3 frames at the reel join or leave 1-3 frames of black lead or tail leader.

 |  IP: Logged

Monte L Fullmer
Film God

Posts: 8161
From: Nampa, Idaho, USA
Registered: Nov 2004


 - posted 12-02-2016 04:56 PM      Profile for Monte L Fullmer   Email Monte L Fullmer   Send New Private Message       Edit/Delete Post 
There was one step I forgot to mention since I haven't ran a Cine unit since the mid 90's, which were V8r units, and this was:

When doing the trick I do, roll the INT sprocket until it just stops and is locked by the cam, lace up the unit snug, then back off four sprocket holes on the large lower hold back sprocket, then close the pad roller.

This gets the 21 frame offset.

We had 60ft throws to the screen.

-Monte

 |  IP: Logged

Mark Gulbrandsen
Resident Trollmaster

Posts: 15885
From: Bountiful, Utah
Registered: Jun 99


 - posted 12-03-2016 10:11 AM      Profile for Mark Gulbrandsen   Email Mark Gulbrandsen   Send New Private Message       Edit/Delete Post 
Jonathan,

Place "picture start" in the gate and sound start mark at the scanner. Then adjust the lower loop so it all looks right and no film is rubbing. Then count the perfs in that lower loop for refrence.

Sam, I am pretty sure Phillips got that right. I don't ever recall lacing up a DP-70 and not being able to get picture start in the gate and sound start on the scanner.

quote: Leo Enticknap
With the OEM Philips head, I agree that the intermittent loop does look smaller than comfortable with the offset threaded correctly. With the Kinoton LED replacement installed, though, it looks about right to me.
There is some adjustment that can be made to at least one of those rollers below the intermittent sprocket and there is not an actual standard position for it. Just what works. See part number 22 & 23 in the included drawing which allows pivoting of the roller.

 -

 |  IP: Logged



All times are Central (GMT -6:00)  
Post New Topic  Post A Reply Close Topic    Move Topic    Delete Topic    next oldest topic   next newest topic
 - Printer-friendly view of this topic
Hop To:



Powered by Infopop Corporation
UBB.classicTM 6.3.1.2

The Film-Tech Forums are designed for various members related to the cinema industry to express their opinions, viewpoints and testimonials on various products, services and events based upon speculation, personal knowledge and factual information through use, therefore all views represented here allow no liability upon the publishers of this web site and the owners of said views assume no liability for any ill will resulting from these postings. The posts made here are for educational as well as entertainment purposes and as such anyone viewing this portion of the website must accept these views as statements of the author of that opinion and agrees to release the authors from any and all liability.

© 1999-2018 Film-Tech Cinema Systems, LLC. All rights reserved.