Exercising audiotapes

While I applaud Sarita Bullard Oertling and the Moody Medical
Library at The University of Texas Medical Branch for their efforts
in exercising their tape collection it seems that some of my
comments on this subject have been combined with other comments from
other sources as well as with the decisions made locally.
Unfortunately some of the procedures outlined were NOT my specific
suggestions, and I feel the need to comment on this email.  As a
general rule, VidiPax does *not* make recommendations in these
matters, although we do refer to manufacturers recommendations and
industry recommendations such as SMPTE RP103 and similar documents.

>An important recommendation in the conservation of audiotapes is to
>"exercise" the tapes, which involves rewinding to the very end of each
>tape at normal playback speed.

It is *very* *very* *very* important for audio tapes *not* to be
left in a rewound condition due to problems with audio print
through.  Print through is a condition whereby  sections of tape
with a strong magnetic pattern come into contact with a section of
tape with a very low or no magnetic pattern and some of the strong
image is transferred to the weak one. The standard industry approach
to minimize this problem is to store all audio tape tails out -
which in the cassette media is to be stored in the fast forwarded
position.  Audio cassettes in general should NOT be recorded on both
sides to minimize the risk of cross-talk from adjacent tracks.

Also we do *not* suggest that the exercising process be done in
"real time" or in the play mode.  We recommend that the tapes be
advanced in fast forward or rewind.  Playing the tapes places them
under stress from the pressure between the capstan and pinch roller
which is not necessary to do if the tape is not being played back to
listen to.  Also, you very well may get a better wind in the fast
forward or rewind modes depending on the machine. It also is much
more practical to exercise tapes in fast forward and rewind.

>A commercially available cleaning and
>demagnetizing cassette containing small brushes, to which a special solution
>is applied, was used.  The removable brushes were cleaned periodically with
>soap and water, dried, and then reinstalled into the cassette.

I am not familiar with the "cleaning and demagnetizing" cassette
mentioned above, and based on the description I doubt it is very
effective.  Most manufacturers recommend that heads and ferric
elements of the tape transport be demagnetized by a point
demagnetizer, which is an inexpensive accessory that is usually
available from an electronics store like Radio Shack.  Demagnetizing
must be done carefully or you can actually magnetize the transport
and cause damage to the tapes that run through it.  Heads and metal
parts of the transport are generally cleaned best with Isopropyl
Alcohol and a lint free swab which is also specially designed for
that purpose.  Rubber parts in a transport should not be cleaned
with alcohol, but should be cleaned with a special solvent that is
also available at electronics stores or from the manufacturer.  I
have never heard of a solution that is safe for both, but it MAY
exist.

Temperature and humidity suggestions are an area in active
discussion, but I think that most parties would agree that the
temperature and humidity mentioned above is most certainly too hot
and too humid.  Long term storage recommendations from manufacturers
usually suggest lower humidity (30% area) and temperatures in the
60's.  Many people currently think that the temperatures should be
even colder than this--some suggest *almost* but not freezing.

I apologize for any confusion this may have caused, but I would like to
point out that more information is available on our web home page at:

    http://www.panix.com/~vidipax/

which is also linked to the CoOL database.

    **** Moderator's comments: and CoOL has a link to the VidiPax
    page on the Commercial Services page

Jim Lindner
VidiPax
The Magnetic Media Restoration Company

                                  ***
                  Conservation DistList Instance 8:92
                   Distributed: Sunday, May 21, 1995
                        Message Id: cdl-8-92-004
                                  ***