Hi Sarah:

Your explainations are the clearest I've seen so far. Thank you!

I agree with you, some science needs to be applied to tapes as they age. I'm wondering if it's 
possible to gauge amounts of degradation, can a scale be established? Then, can it be determined if 
a tape farther along the degradation scale will always need a longer baking time? Or is something 
else going on?

In any case, it would be very helpful just to establish a means of measuring degradation and 
quantifying it. I have some known sticky tapes that have not been baked and some known sticky tapes 
that have been baked if someone needs samples for this research. I would assume this is a chemistry 
and/or physics project? To be honest, I'm surprised the P&E Wing of NARAS hasn't gone to the record 
companies and gotten money raised for this research. It has tremendous bearing on vaults and 
commercially valuable master tapes. If we can understand how the degradation works, what its 
timeline is likely to be, we can then study whether super-dry storage makes any difference.

-- Tom Fine

----- Original Message ----- 
From: "Sarah Norris" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Thursday, April 04, 2013 4:40 PM
Subject: Re: [ARSCLIST] Sticky SHRED

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]