The Vitaphone discs did have a start point, which was ultimately your sync mark. It was a little arrow on the inner point of the film, on which you synced up to a start point on the film. The difficulty, of course, was if the film broke, you couldn't just slug it with one frame of leader because the cement splice couldn't take the stress. Instead, you had to cut two or more frames out, leaving a noticeable slug. Sound-on-film, of course, was no problem, because there's no way for it to drop out of sync.
With proper care, even on manual rewinds (which should all have a tension brake on them), a film should be returned in the same condition as the day it came in.
From: George Brock-Nannestad <[log in to unmask]>
To: [log in to unmask]
Sent: Thursday, June 25, 2009 4:45:52 PM
Subject: Re: [ARSCLIST] Recording Innovations
From: Patent Tactics, George Brock-Nannestad
just a short remark, re Bob Hodge:
> Competent projectionists would splice in black film equal to the number of
> frames damaged. Just a normal part of projection.
> Ideally, the rotational pivot should be midway in its travel for maximum
> flexibility. It couldn't rotate 360 degrees due to the leads from the
> tonearm. But more than enough to compensate for subtle difficulties. And why
> a second set of discs were shipped with each film requiring them.
----- at first I thought that having the pivot midway would compensate for
having put too many black frames into the gap, but then I remembered: there
is no synchronization mark on the Vitaphone disc, so when it is first put on
the turntable you do not know where it is on the turntable. For this reason
you might have to go back or forth to find the sync.
----- by the way, the black film replacement would only work for silent
stock. When a frame was lost in a sound film, the best you could do as a
projectionist was to paint fade-in and fade-out on either side of the splice.
Re-sync would not happen after 20 frames anyway. I think that my worst
experience as a projectionist in our little cinema (35 mm Ernemann, though!)
was in manual rewind. If you got the reels up to speed and lost power in your
winding arm towards the end, the loop would rise above the reels, and if you
were not diligent, above 3 feet in height would threaten with havoc. What
could you do, except clamp your hand on the other reel, getting burn tracks
in your hand. I wore a left-hand leather glove after that. You did not want
to use the brake, because it would slow down the process to a safe speed.
Films had to take a lot of abuse (the reason why nitrate survived for so long-
-it was not only more transparent but also much tougher than acetate)