Thanks to Marie O'Connell and Corey Bailey for your suggestions. I had
success with the two reels of PEM-469. I posted a short note in my blog
http://richardhess.com/notes/2012/02/26/agfa-pem-469-success/
but it really points to the degrading tapes page...I've added the
following to it:
http://richardhess.com/notes/formats/magnetic-media/magnetic-tapes/analog-audio/degrading-tapes/
(You don't need to go to the links..the updates are below).
I put Agfa tapes in their own section as they don't really belong under
Classic Sticky Shed since we are not at all in agreement about baking.
[added 2012-02-26] One fascinating perspective is emerging from ongoing
discussions on the Association of Recorded Sound Collections email list
(ARSC List): different tape types in different parts of the world may
behave differently. Again, this comes down to plant-to-plant variations
at least and perhaps formula and/or raw material differences. A factor
that may have caused the differing formulations could be different local
environmental regulations for each plant, but that is mostly conjecture
on this author's part, although there were some studies from Alabama
attempting to address the pollution from the Ampex/Quantegy plant in
Opelika.
[added 2012-02-26] The remainder of this update focuses on Agfa PEM 469,
see notes below.
-----
***Agfa Tapes* (updated 2012-02-26)
*Agfa PEM-526* exhibited dry shedding. See our article here
<http://richardhess.com/notes/2009/01/30/back-coat-turning-to-powder/>.
Although a similar condition was reported with PEM-469, experience has
shown 469 to be more like sticky shed in this regard. It is definitely
another variant of Soft Binder Syndrome (or SBS).
*Agfa PEM-468, PEM-469* There are mixed reviews on these tapes and most
of the bad tape was recalled and transferred at Agfa's expense. This was
supposedly affecting only a half-year's worth of batches from pre-1990.
Unike Ampex/Quantegy, we do NOT recommend baking Agfa tapes as a matter
of course, based in part to our experience with the PEM-526 and this
article <http://www.tomshardware.co.uk/forum/page-42797_32_0.html>,
although the baking temperature may have been a bit too high (60 °C) in
that discussion.
The author of these pages encountered two very nasty reels of one-inch
Agfa PEM 469 in 2012-02 (recorded in 1988-01) that shed a waxy
clear-to-slightly-yellow exudate from the mag coat. The mag coat was
also transferring slightly to the back coat which was then coming off on
the capstan (which presses against the back coat side of the tape).
After consultation on the ARSC List and receiving replies from Marie
O'Connell in New Zealand and Corey Bailey in Los Angeles, I decided to
continue with the non-baking recommendation as there was just too much
conversation on the Web and ARSCList against baking to make me feel
comfortable.
The tape's mag coat was run over a Pellon pad in library wind and then
over a D5-soaked Pellon pad, also in library wind. D5 was generously
applied to the heads and fixed guides immediately before the transfer.
We applied about 2.5 ml (cc) of D5 to each tape. Note D5 is also known
as decamethylcyclopentasiloxane, Siloxane D5, CAS # 541-02-6, and
sometimes referred to as Cyclomethicone (generally in regards to the
product as produced by Dow Corning). It is found in many personal care
products and has recently been declared safe for the environment by the
Canadian Ministry of the Environment
<http://www.cdr-siloxaned5-bor.ca/default.asp?lang=En&n=9320DEF6-0&offset=3&toc=show#s2.1>.
The worse of the two tapes was stopped twice to re-clean the heads and
reapply D5. It is not clear to me if the slight loss of brightness was
due to reproduce or recording issues, as apparently some batches of this
tape shed when originally manufactured.
This tape has been reported stable in parts of Europe, but Ms. O'Connell
confirmed the clear-to-yellow waxy exudate and indicated that it was one
of her least favourite tapes to transfer. She reported that it did
respond to her isopropyl drip technique
<http://richardhess.com/notes/2006/03/09/wet-playing-of-reel-tapes-with-loss-of-lubricant-a-guest-article-by-marie-oconnell/>
and Mr. Bailey suggested gentle baking (about 48 °C for 24 hours) which
allowed him to have success with the tape. He also reports success with
lubricants from The Last Factory here
<http://www.baileyzone.net/analog%20tape%20diy.htm> (second to last
section).
*
*
--
Richard L. Hess email: [log in to unmask]
Aurora, Ontario, Canada (905) 713 6733 1-877-TAPE-FIX
http://www.richardhess.com/tape/contact.htm
Quality tape transfers -- even from hard-to-play tapes.
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