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Re: [ARSCLIST] Fwd: Sticky AGFA PEM 469

Hi Peter,
I take the list in digest form, so my replies are a bit slow, and maybe someone has already made the point. The closest I've found to what you're looking for is a paper by Kevin Bradley, read at the Joint Technical Symposium in 1995 and published in their proceedings. I'm sorry I only have the title at hand, 'Anomalies in the treatment of hydrolysed tapes', but if I remember correctly he came to the conclusion that treble was affected slightly after baking, maybe 0.5 dB, but I don't remember what the outcome was after several baking cycles.
I believe the proceedings can be ordered through George Boston who was secretary for JTS then.

Tommy Sjöberg
Folkmusikens Hus
SE-795 31 Rättvik

On Apr 7, 2008, at 12:22 PM, peter@xxxxxxxxxxxxx wrote:


 While working on the AES and ANSI technical commissions on magnetic =20
 stability, we reviewed large numbers of documents from both private =20
 government labs from around the world (US, Canada, Japan, =20
 Germany ..., 3m,
 Agfa, Sony...) and we were never able to locate any repeatable =20
 testing that proved a signal deterioration associated with multiple =20
 of a tape.  There were anecdotal reports of such but no laboratory =20
 to back up the anecdotes.  If you actually have quantifiable =20
 results to back up a loss of signal that can be specifically =20
 attributed to
 baking of a tape (and contains sufficient controls in the testing =20
 to isolate the baking as the cause), I would love to see the results =20
 of the
 testing.  As I said, we looked for such a study and were never able to
 locate one.  We found lots of other interesting results but not this =20
 one, in

 Peter Brothers

Tape restoration and disaster recovery since 1983

 -----Original Message-----
 From: Association for Recorded Sound Discussion List
 [mailto:ARSCLIST@xxxxxxx] On Behalf Of Charles A. Richardson
 Sent: Saturday, April 05, 2008 10:27 AM
 To: ARSCLIST@xxxxxxxxxxxx
> Subject: Re: [ARSCLIST] Fwd: Sticky AGFA PEM 469

Dear Tom: What Claus describes with Ampex sticky tapes is exactly my experience -- they go sticky again after about 30 days. What Claus did not touch on but has definitely been my experience is that there is audible deterioration after two or three bakings. Treble dropoff, fuzzy upper midrange, the kind of stuff you hear in multi-track if it's been run thru too many times for endless punch -ins.

 I have spent the last 10 years researching the causes of such tape
 problems.  My own research, as well as the research of a well-regarded
 forensic chemical laboratory which I engaged to find and explain these
 complex chemical issues, confirms that the new remediation method that
 I devised is very effective and restores the tape to excellent sonic
 and mechanical performance.  Although my research continued and
 provides more information today, the paper I presented at AES in 2006
 in San Francisco provides an explanation and drawings for both these
 mysteries, namely why the tape becomes sticky again after baking, and
 why sticky tapes have increasing high frequency losses and drop outs.

 If you contact me off list, I would be glad to send you a copy of my
 paper (and a newer follow-up paper) for your review and comment.  In
 addition I am working on new papers (and a prototype machine to
 mechanize my process) which will soon be released.

 Charles A. Richardson
 Richardson Magnetic Tape Restoration
 1938 Baltimore Annapolis Boulevard
 Annapolis, MD 21409--6248
> 410-757-3733

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