Re: [ARSCLIST] Risk assessment tool

["Scott D. Smith" <sdsmith@xxxxxxxxxxxxxxxx>]

To confirm Mike's findings, we have also encountered any number of 
"white box" second grade tapes, mostly from the mid-fifties to early 
seventies, which exhibit what may appear at first glance to be sticky 
shed, but in fact suffer from other manufacturing problems (which is why 
the ended up in the second grade bin!). Some of these may respond to 
baking, others may not. (We just recently did a whole batch of tapes 
recorded on 1/4" 1 1/2 mil.acetate stock from a company out of New York 
called Magna-Reel. The stock appears to be second grade Ampex 611, with 
very poor slitting and areas where the coating was applied unevenly, in 
addition to some stiction).

Unlike stocks from Ampex, 3M, AGFA/BASF and others, whose 
characteristics have been well documented, the off-brand tapes are a 
challenge unto themselves. The tapes are seldom the same, even if they 
appear to be from the same batch, and vary wildly in both their physical 
and magnetic characteristics. All in all, a real nightmare for an archivist.

My advice is to tread carefully, and don't do any treatment that may be 
irreversible. (It should go without saying that you should never attempt 
to bake an acetate/mylar based tape, but I thought it would bear 
repeating-just in case a novice is reading through these posts!)

I would be most curious as to whether Bob could identify the two tapes 
that wouldn't respond to baking, though.

Scott D.Smith

Chicago Audio Works, Inc.

Chicago, IL

*****************************



Mwcpc6@xxxxxxx wrote:

> In a message dated 1/4/2006 11:33:25 AM Eastern Standard Time, 
> micasey@xxxxxxxxxxx writes:
> Bob,
>
> I'm curious about the two sss tapes that baking did not restore--any
> thoughts on what might have been different with those two tapes compared
> to the countless others that were succesfully baked?
>
> Mike 
> ***************
>
> Not that it relates to Bob's case, but similar tapes that I've found were 
> green-box "Shamrock" reels in which the oxide did not seem sticky, but partly 
> smoothly transferred to the backing of the previous layer, leaving effectively 
> double coated tape.
>
> Considering the source, this may have represented a catastrophic 
> manufacturing defect that was passed on to the "white box" market.
>
> Mike Csontos
>
>
>