Dave:
I was also at the meeting last night and agree that the response from the
audience to Mr. Richardson's presentation was less than enthusiastic. Of
course, one has a fairly hard sell in a room full of engineers, most well
into their second 1/2 century, when your message is that they have all
been
dead wrong about a basic principle in their field for some 20 or 30 years.
Of course, there is the other side of the issue. Mr. Richardson's
presentation, while interesting, contained very little hard data. Mr.
Richardson stated that he had proof that the original theory concerning
binder hydrolysis was wrong but supplied no hard evidence of that proof.
Unfortunately, holding up a small piece of tape floating in a bottle of
water that he states is unaffected by the exposure and hearing a few clips
of audio exhibiting improved signal response after his treatment do not in
any way prove that binder hydrolysis is a myth.
Mr. Richardson, as he stated repeatedly, is an engineer and not a
chemist.
As such, he indicated that he could not present the chemical proof of his
assertions. The proof, he said, needs to be supplied by the chemists he
has
employed to do the testing and that proof was not offered at the
presentation. In addition, Mr. Richardson has a patent on his new process
and, understandably, may be somewhat hesitant to divulge too much precise
detail until the commercial development of the process is further along.
The only question I posed to Mr. Richardson at the meeting was: If his
theory states that binder hydrolysis is not actually happening and "sticky
shed" is exclusively contamination of the tape from migrating elastomers
from the backcoat, how does he explain that extraction testing by a number
of laboratories has resulted in a greater weight of material identified as
"binder hydrolysis residue" than there is total material in the backcoat
of
the tested pieces of tape?
For those not familiar with extraction testing, the process is basically
as
follows: 1) A piece of tape is identified as having "sticky shed"- it is
assumed to be hydrolyzed. 2) A length of this tape is cut from the roll
and
the recording layer is peeled off, discarding the base-layer and backcoat
which are not being tested. 3) The resulting strip of binder (recording
layer) is weighed. 4) The binder is then placed in a chemical bath. The
chemical used will dissolve the low-molecular-weight hydrolysis residue
(oligomers) but will not dissolve intact polymers from the binder or the
magnetic particles. 5) The strip of binder material is removed from the
bath, dried and weighed again. 6) The original weight of the strip of
binder is compared to the resultant weight, after extraction, to determine
the amount of material that dissolved. (Note: One problem with accurate
readings of oligomer residue present using this test is that the chemical
will dissolve both the hydrolysis residues (oligomers) and any lubricants
in
the binder.)
The problem I have with Mr. Richardson's assertion that all the sticky
shed
problem comes from material migrated from the backcoat is as follows: When
the extraction test is done, the existing backcoat has been removed and is
not being tested. This means that there is a volume of backcoat material
that is not being weighed. Despite this, some of these tests have
resulted
in a greater volume of material being dissolved than can be accounted for
by
either the entire weight of the original backcoat for the strip or from
the
lubricants in the strip. If there is no breakdown of the binder, as Mr.
Richardson states, what is being extracted and where did it come from?
His
assertion that no material breakdown is occurring in the binder seems to
be
directly contradicted in other tests.
All this said, I do not think that Mr. Richardson's results should simply
be
ignored or denigrated. I believe that they need closer examination and
consideration than was apparent at the meeting. For this we need more
data.
I have actually seen sticky shed on non-backcoated tape, but it is rare.
If
it occurs on non-backcoated tape, the backcoat cannot be the only cause-
but
why is it so rare on non-backcoated tape? The answer could be that the
manufacturers changed the binder chemistry at around the same time they
started back coating the tape. Another, possible, answer is that
something
in the backcoat could be acting as a catalyst to increase binder breakdown
in the recording layer.
I, personally, do not think Mr. Richardson is correct in his analysis that
the entire problem is migrating elastomers from the backcoat. I do,
however, find his assertions intriguing and am willing to see if more data
is forthcoming. He may have found an important factor that can shed
additional light on the problems of tape degradation. It is still too
early
in my opinion, with the data available, to really determine what it is he
has found.
Peter Brothers
President
SPECS BROS., LLC
(201) 440-6589
www.specsbros.com
Restoration and Disaster Recovery Service Since 1983
-----Original Message-----
From: Association for Recorded Sound Discussion List
[mailto:ARSCLIST@xxxxxxx]On Behalf Of dave nolan
Sent: Wednesday, April 13, 2005 11:16 AM
To: ARSCLIST@xxxxxxxxxxxx
Subject: [ARSCLIST] Rezerex presentation AES NYC 4/12(was Re: Baking
tapes and high frequencies)
Hello all -
I was at the NYC AES presentation by Charles Richardson last night on his
new take on sticky-shed syndrome, and his "Rezerex" process for tape
restoration. Some basic info is available at his website:
http://www.sascom.com/rezerex/
For those unfamiliar with his work, Richardson is saying that in
fact, there
is no such thing as oxide binder hydrolysis, and that the culprit
is instead
breakdown of the backcoating found on most post-1970 tapes. According to
him, the "oxide hydrolysis" theory is a case of "common knowledge" that
we
have all accepted as fact without investigating further or re-checking
the
basic scientific work that originally came up with the thesis.
He claims to
have had numerous laboratory tests conducted that completely
contradict the
theory of oxide binder hydrolysis and instead point to breakdown of the
backcoating as the cause of "sticky-shed" syndrome.
He has come up with a (patented) process to chemically remove the
backcoating layer from the back of affected tapes, and to
mechanically clean
the oxide side of traces of backcoating residue, restoring tapes to a
permanently playable condition (much like the pre-1970
non-backcoated mylar
tapes we have all worked with).
At times the presentation had a bit of the "sales pitch" feel to it -
like
his holding up a bottle of water with a piece of tape in it to
"demonstrate"
that there was no hydrolysis occurring, or his claiming that baking was a
"nail in the coffin" of chemically degraded tapes. The sales pitch aside
(and to be sure, I am not a chemist), I think he made a fairly
good case for
his thesis.
It was also interesting to see a couple of folks try to poke holes in his
theory, but the major objections seemed to come from folks saying that
baking was "good enough" or "time tested", and that a new process for
preserving original masters was not desirable or necessary. To me, it
almost seemed like a couple of people were defensive about his claims
that
baking tapes was destructive (perhaps because they had some part of their
reputation or business tied up in tape-baking?). One attendee of the
meeting even seemed to intimate that the original masters were
more or less
expendable once the audio had been digitized, and that a process
to preserve
reel-to-reel masters long-term was a bit of a waste of time.
I understand that we've all placed our eggs in the baking basket since
the
solution was first suggested by Ampex, but I would have hoped that a room
full of engineers would have been more hopeful or excited about the
possibility that someone had stumbled onto a completely different (and
possibly more correct) approach to tape preservation.
Personally, I am interested in preserving original masters as long as
possible, not just as historical objects, but also in the hopes of ever
better future transfer and restoration technologies. If Richardson's
Rezerex thesis and process are indeed correct, this could be a major
breakthrough for tape preservation efforts worldwide.
The big drawback at this point is the fact that he has yet to make the
process either cost-effective or automated, as things are still in the
development stage.
I would be very interested to hear what other folks on this list
have to say
about this whole Rezerex thing - from whether they think Richardson's
chemistry and physics are correct, to whether folks think that baking is
"good enough" and a new process might not be desirable irregardless of
its
possible benefits.
I am just a moderately experienced tape archivist with a couple of small
projects under my belt, so I would really like to hear from folks who
have
more experience in the science or the general
archive/administration issues
this brings up.
dave nolan
nyc
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