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RE: arsclist water damaged tapes.
A few quick notes about handling water damaged tapes.
First: I believe that many DAT's use MP recording pigments. The idea of
holding water damaged tapes in cold water works for oxide formulations but
can quickly destroy MP and ME tapes. The recording pigments in MP tapes are
subject to oxidation. To protect the recording pigments from atmospheric
moisture they are coated with a very thin ceramic "armor". This works
fairly well during regular usage but the ceramic coating frequently fails to
protect the pigments when submerged. Oxidation can begin in a short time
and can rapidly cascade through the tape making it totally unrecoverable.
Second: While it is important to remove potentially damaging chemicals from
the tape surface, magnetic tapes should only be rinsed in cool, distilled
water to avoid subjecting the tapes to additional contaminants. Tap water
usually contains chlorine which is often more damaging than whatever
impurities were in the original flood waters.
Third: We recently received a group of tapes that had previously been
"recovered" by freeze-drying. These tapes were 8mm video. Over 60% of the
tapes had ripped due to the freeze-drying process. High levels of moisture
will cause the tape pack to become loose, allowing portions of the tape to
touch the inside of the cassette shell. As the tape dries, it will stick to
the inside of the shell. This adhesion, compounded by the rapid dimensional
changes caused by temperature and moisture alterations in the tape during
freeze-drying, can result in tearing. If your tapes are rewound this isn't
a great problem as you can resplice to the hub. If the tapes are not
rewound, you can easily rip the tape in the middle of the recording.
If you want some specific advise on what to do with your wet tapes, drop me
an E-mail or give me a call.
SPECS BROS., LLC
TAPE RESTORATION AND DISASTER RECOVERY
> -----Original Message-----
> From: owner-ARSCLIST@xxxxxxxxxxxxxxxxx
> [mailto:owner-ARSCLIST@xxxxxxxxxxxxxxxxx]On Behalf Of Karl Miller
> Sent: Sunday, June 24, 2001 12:52 PM
> To: ARSCLIST@xxxxxxxxxxxxxxxx
> Subject: arsclist water damaged tapes.
> As some of you may know, Houston was hit by floods recently. Fortunately
> most of the archive of broadcasts resides in our archives here in Austin,
> only the most recent performances were under water. These are all DAT
> Any advice as to the proper way to deal with these would be most welcome.
> At the advice of someone else, they have been left sealed in water...
> Feel free to post to the list or email me directly.
> Karl Miller
> University of Texas at Austin
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