Unless I have overlooked an important post on this topic or am
misunderstanding something, what I find missing in this discussion is
any comment on the number of different oxide formulations by both age
and manufacturer that have been investigated with respect to binder
hydrolysis. We know from experience that the phenomenon affects
preponderantly those tape types manufactured after 1975, Earlier
formulations exhibited other problems but were stable with respect to
binder hydrolysis. If my surmise is correct, there is much further
study to be carried out on the problem in order to discover
preservation and playback strategies that are more than anecdotal..
On Thu, Apr 4, 2013 at 4:40 PM, Sarah Norris <[log in to unmask]> wrote:
> Hi, Tom (and list):
> Please find responses below:
>>Would you, for us non-scientists on the list, summarize Bradshaw's
> thinking and the opposing view(s)? Please try to keep it in the realm
> of what an English major or at least what a MLS major can comprehend.
> A more thorough description is in my post from April 2, but here's a
> very abbreviated summary:
> Bertram / Cuddihy's model says baking works because it repairs the glue
> that holds the media together.
> Bradshaw / Bhushan's model says baking works because it makes the media
> and other degraded fragments hold hands for awhile.
>>Do any of the theories you explored about what causes sticky-shed
> reveal why baking times would be increasing as the tapes get older?
> The models summarized above answer the question, "Why does baking work?"
> The question we're asking now is something closer to, "How are tapes
> aging?" I think the first question probably is relevant to the second
> question, but probably not in a direct, straight-line kind of way. It
> makes logical sense that longer required baking times indicate more
> advanced degradation. Is that really the case? Now might be a great
> time for a series of studies, one every few years, comparing required
> baking times with degraded binder in tape samples!
> Sarah Norris
> Texas State Library and Archives Commission
> phone: (512) 463-5446
> fax: (512) 463-5430
> e-mail: [log in to unmask]
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Delray Beach, FL 33483