Charles:
While working on the AES and ANSI technical commissions on magnetic =20
tape
stability, we reviewed large numbers of documents from both private =20
and
government labs from around the world (US, Canada, Japan, =20
Germany ..., 3m,
Agfa, Sony...) and we were never able to locate any repeatable =20
laboratory
testing that proved a signal deterioration associated with multiple =20
baking
of a tape. There were anecdotal reports of such but no laboratory =20
testing
to back up the anecdotes. If you actually have quantifiable =20
laboratory
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
protocols
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
specific.
Peter Brothers
SPECS BROS., LLC
973-777-5055
peter@xxxxxxxxxxxxx
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
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