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Re: [AV Media Matters] Sony 3/4 KCA tape

Having produced commercials for a TV station and dealing with 3/4" playback
(however many years ago it may have been), I renewed many brands and lengths
of 3/4" tape.  Thirty an 60 second commercials use a very small part of even
a short 10 minute tape, but repeated playback would really wear out that
first bit of tape.  After extensive use we would simply FF>> the tape 2 min.
from the leader then hand pull the tape out the front opening, pulling all 2
minutes back to the leader, and cut it off and use a splicing tab (from
Comprehensive) to give us a brand new "8 minute" tape.  Occasionally a leader
would break but is simply re-slotted back into its hub (by opening the
housing).  Using cotton "film handling" gloves is recommended.

You mention adhesive.  To my recollection, the leaders are held on the hubs
by a slotted key that pinches the tape inside the hub.  Correct me if I'm

Moderators comment:
With 3/4" Umatic tapes the clear (and VERY tough) leader is indeed inserted
into a slotted key in the hub on one end.  This attachment has proven to be
pretty sturdy compared with the attachment of the magnetic tape to the
leader which is on the other end..... This attachment was usually made with
a piece of adhesive tape that is usually silver in color and appears to be
a mylar of some sort although I have never checked out the composition -
the problem is with the adhesive on this "splicing tape".   Often the
adhesive appears to have dried out and with winding of any sort will often
fail.  Even more of a problem - if it fails while inside a machine, the
adhesive tape itself can fall inside the transport and make a mess of
things.  In addition, the adhesive residue is left on the magnetic tape as
well as the leader.  I cannot say that any particular vendors product is
more prone to failure of this type then others, but it is a very common
problem that we see all the time with older 3/4" media.  By the way, one
issue of low humidity is the effect that it has on labels and label
adhesive.  While there certainly appears to consensus as to the benefits of
a low humidity environment to the tape itself - labels are quite another
matter.  Cool and dry environments can cause many label adhesives to
failure - and the environment MAY accelerate the failure of other adhesives
such as the leader tape mentioned above.  I am not necessary recommending a
higher humidity - just pointing out the issue. My experience is that in an
archive - tapes without labels are a BIG problem.


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