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Re: Sony HD Telecine



<< My biggest potential problem with the return of the film chain approach is
not film handling, but mechanical maintenance. (deletia) Video facilities (as
opposed to optical houses or film labs) are not used to complicated
mechanical movements, or the level of maintenance probably required, at
either the engineering or operational level. >>

Assuming Sony uses a mechanical intermittent sprocket motion, there is no
reason it should be complicated or difficult to maintain.  Movements such as
the Geneva motion have been used in film projectors since the turn of the
century and have two or three moving parts at most.  The complexity is in
manufacturing them to the required degree of accuracy and hardening the cams
and pins sufficiently to last a reasonable length of time.  Maintenance is
keeping them properly lubricated, and troubleshooting means that you replace
the parts with a new set when they wear out (as evidenced by excessive noise
or jitter).  I'd have to wonder about any video maintenance department that
can clean tape paths and replace upper drums and pinch rollers in VTRs, but
couldn't take adequate care of this type of device!

However, there is a reason to be concerned, particularly when dealing with
valuable one-of-a-kind films.  Most film tears and breaks start with torn or
damaged perfs, so if you're going to stress the perfs by using them to move
the film, there's always a possibility that a previously damaged or weakened
perf will give up the ghost and take two, three, maybe more frames with it.
 This is particularly troublesome with old, archival footage where shrinkage
makes the perfs fit tight on the sprocket teeth.  But on very rare occasions,
new film may be encountered with badly punched perfs that won't hold up for
long.  

On the other hand, most of us have probably seen test loops (if nothing else)
with frames that are literally ripped halfway through, but still pass through
capstan-type telecines without further damage.  To be as safe as possible
when using a sprocket-drive device to handle film, one must completely
inspect the film and repair any faulty- looking perfs.  This is not a common
practice in telecine now because capstan machines make it generally
unnecessary.

Cordially yours,
Christopher Bacon


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