Degradation of VHS Tapes

Colin Williamson <smileplas [at] aol__com>, on behalf of Antonio Gorni
<agorni [at] iron__com__br> writes

>    At least here in Brazil some VHS video-tapes eventually present
>    the formation of a white powder over its surface. Apparently it
>    is some kind of mould. The tapes became useless and must be
>    cleaned.
>
>    Does anybody know the cause of this phenomenon and how it can be
>    avoided?

Usually mold on videotapes is present on the edges of the tape and
does not penetrate the "pack" of the tape because of the tightness
of the wind.  The description of "white powder" could mean any
number of things--of course including mold.  It is possible,
however, the powder you speak of is actually a lubricant that has
migrated out of the tape--this is particularly  probable of the
surface is thinly "coated" with this powder. In either case the tape
should be cleaned by a professional to remove either the mold or the
lubricant that is no longer acting like a lubricant.

The probable cause of these problems is high (perhaps *very* high)
humidity. Tapes need to be stored in a cool and dry environment.
While some manufacturers do add an anti-fungal ingredient to some of
their tapes, I have been told that these ingredients are quite mild.
Mold problems with all magnetic recording tape is quite common in
areas of high temperature and humidity such as the Caribbean
nations.

Jim Lindner
VidiPax
The Full Service Magnetic Media Restoration Company
212-563-1999 ext. 102

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                  Conservation DistList Instance 12:47
               Distributed: Wednesday, November 25, 1998
                       Message Id: cdl-12-47-001
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