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Re: [ARSCLIST] Can Magnetic Tape Be Frozen?
In addition to Richards comments - there is a big concern with pack tension. When very cold, the pack will tend to loosen and may actually sag off of the pack (in pancake) or onto the flanges of a reel. When acclimitization occurs the tape pack willl "re-tension" but there is no way to really control precisely how it will re-tension and there is no reason to believe that it will re-tension in precisely the way it was before relaxing. Pack tension/pressure is very important and the poor wind that could occur after re-tension can cause all sorts of problems since it is really uncontrolled.
I think that this is really the major issue. While there is certainly issue with lubricant migration - i have not seen any real work done stating that the lubricant remains in an archival tape anyhow. Meaning - how much lubricant remains after 30 years? That is an unknown and will obviuosly vary by the tape type, how it was stored, the type of lubricant, and the amount that happened to be in a specific batch in the first place. All variables. I have seen NO credible research on this subject. It is all just best guesses at this point (including mine!).
There are other issues with freezing that have not been adequately explored as well. I have had a discussion with a colleague who has mentioned that after freezing a test sample there appeared to be microscopic cracks in the binder. What effect (if any) that will have on longevity and playback are all unknowns.
At this point in time - my feeling is that he far bigger risk is that of obsolescence. I mean if you can extend the life by 300 years by freezing - then great. But finding a 1/4" half track studio quality machine that works on ebay might be a bit harder 300 years from now.
I strongly feel that we need to move in a different direction - and that direction is one where we embrace the concept of continual management of an asset which means that migration is one of the things that "we do" for electronic media as a matter of course. Active management versus putting it on a shelf type "management". While extending the life of materials is certainly a worthwhile pursuit, I feel that it becomes a moot point from a practical point of view.
> -----Original Message-----
> From: Richard L. Hess [mailto:ArcLists@xxxxxxxxxxxxxxx]
> Sent: Wednesday, December 1, 2004 06:17 PM
> To: ARSCLIST@xxxxxxxxxxxx
> Subject: Re: [ARSCLIST] Can Magnetic Tape Be Frozen?
> At 11:56 AM 12/1/2004 -0500, Watsky, Lance wrote:
> >This is being posted for Beth Delaney, Nederlands Institute for Sound and
> >"Can anyone tell me if it is acceptable to freeze magnetic sound film? I
> >don't seem to find in any literature that this is not a good idea. Often
> >the literature states that it is recommended to "freeze acetate film", not
> >differentiating between acetate image material and acetate magnetic sound
> >I personally believe that it is probably not recommended, but I wanted to
> >check with the ARSC folks, before responding back to Beth.
> James, everything that I have heard points to your personal belief being valid.
> The reasons that I've heard is that many tapes were made with
> fatty-acid-based lubricants which do not respond well to freezing. While we
> cannot be sure that a given tape was or was not made with a
> fatty-acid-based lubricant, the prudent course is to not freeze any tape.
> With that said, we have two different deterioration mechanisms working:
> (1) The known danger of "vinegar syndrome" in acetate base films -- a
> process that appears to be catalyzed by the iron content of the coating and
> exacerbated by the typical steel cans in which film was commonly stored. My
> personal belief is that we see this more in film than in audio tape for
> several reasons, including the larger amount of acetate present (the
> basefilm is thicker), the greater width of the medium (allowing for more
> buildup of acid in the centre), and the lack of the traditional cardboard
> box for audio tape which possibly acts as a molecular-sieve, absorbing the
> acid which the tape releases.
> (2) The potential risk of damage to the lubricant by freezing.
> If I had a collection of items that were suffering from (1), I would be
> tempted to risk (2) to arrest (1), but that is certainly not an official
> stance or officially sanctioned by anyone, just my opinion. We know (1)
> will destroy the elements. We don't know the long-term risk of (2).
> The following is not for the squeamish:
> The fatty acid used in at least some tape manufacture was sperm whale oil.
> Aurora, Ontario, Canada