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--- Forwarded Message from Lee Ramsdell <[log in to unmask]> ---
>Date: Fri, 12 Sep 2003 13:16:51 -0600
>To: Language Learning and Technology International Information Forum <[log in to unmask]>
>From: Lee Ramsdell <[log in to unmask]>
>Subject: Re: #7242.1 the fate of those tapes once you've gone digital (!)
>In-Reply-To: <[log in to unmask]>
------------------
The reason that your reel to reel tapes dumped their oxide on to the heads
is due to water absorption.. Mylar/Polyester tapes manufactured from the
early 1975s to about 1985 absorb water into the binder and the oxide
becomes a gummy mess that will no longer adhere to the mylar
substrate. The problem is known as Sticky Shed Syndrome. Manufactures
were required to change the binder formula by the United States Government
because the original binder contained a carcinogen. As the manufactures
were in a hurry to make these changes , enough testing was not done and
thus we now have to deal with this problem. If the recorded material is
of value, the tape can be rejuvenated for a short period of time (about 4
weeks) by "baking the tapes in a dehydrator for 4 to 6 hours at about 125
degrees F., then slowly cooled down. This process can be repeated about
three times and after that, the recorded material is lost. If long term
storage of analog tapes is required, tapes should be stored in a vault at
room temperature with a low a humidity as possible. To avoid print
through, tapes must be wound to the other end every year or so.At 01:38 PM
9/12/2003 -0400, you wrote:
>To answer your question:
>
>At Dartmouth all digitized materials are backed up in streaming formats on
>CD ROM, and, more recently, on DVD-R. They also "live" on a pair of
>mirrored servers. All audio files we have are also backed up on CD-R/DVD-R
>in MP3 format on a restricted server. We have kept all master tapes. We
>have also kept tape sets for lab use for those languages that require the
>Record/Playback function of an analog recorder. We'll toss those out once
>DL Recorder is ready for prime time throughout the network here.
>
>We have seen reel to reel tapes recently that literally dumped their oxide
>on the heads of the last professional deck we have (purchased from
>eBay!). We expect the same to happen to cassette tape and to video tapes.
>So archiving the tape media to optical media really makes sense.
>
>The only reason for not tossing out the cassettes is probably proof of
>ownership... and oh, did we have the rights to transfer to another media
>because the original media was crumbling away? But that's an entirely
>different issue!....
>
>Otmar Foelsche </blockquote></x-html>
Lee Ramsdell
Language Resource Centre
Technical Supervisor
142 B Arts Building
University of Alberta
Edmonton, Alberta
T6G 2E6
Tel: 780-492-2142 (work)
780-450-3959 (home)
Fax: 780-492-9112
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