Re: [ARSCLIST] Rezerex presentation AES NYC 4/12(was Re: Baking tapes and high frequencies)

[Andy Lanset <alanset@xxxxxxxx>]

I missed the meeting last night but I'd like to know what this process
would cost per 10.5" reel of 1/4" tape. And, I'd be interested to know
what some of the old hands from 3M and Ampex had to say about this. 

Andy Lanset, Archivist
WNYC New York Public Radio

-----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


> Date:    Tue, 12 Apr 2005 18:58:37 +0000
> From:    jim@xxxxxxxxxxxxxxxxx
> Subject: Re: Baking tapes and high frequencies
>
>> This brings up the question of whether the tape being measured for 
>> dimensional change was hydrolyzed and/or stretched before or after 
>> the recording was made.  If the damage/decay occurred after the 
>> recording, "baking" should return the tracks to a closer 
>> approximation of what the=
> y
>> were originally.  If the tape was hydrolyzed or deformed before the 
>> recording was made, "baking" could alter the dimensions of the tape 
>> to =
> a
>> closer approximation of an undamaged/un-hydrolyzed state and alter 
>> trac=
> king
>> that was recorded on a deformed tape.  Makes it kind of tricky.  How 
>> do=
> you
>> accurately restore a tape to a warped or deformed set of dimensions?
>>
>
> In this particular case the baking was done after the recording. It 
> was a= tape that had an important event on it, and it was pretty hard 
> getting i= t through a transport without drum sticktion that was so 
> bad that i was c= oncerned about stretching the tape by playing it 
> back - and of course the= playback itself was extremely unstable. 
> Since it was a forensic matter a= nd therefore evidence. For this 
> reason I went to the trouble of going to = several locations on the 
> tape (which i carefully marked) and used ferrofl= uid and a microscope

> that had a stage whereby i could move the tape very = carefully and 
> make measurements. It was a pretty fancy microscope - not y= our 
> "normal" scope - I had to go to a company in Rochester NY to get use =

> of it. I did measurements before and after baking and there were 
> changes = but they were not consistent. It seemed that some areas 
> changed different= ly then others, and it was not proportional. In 
> order to do this right on= e would have to do an extensive analysis 
> and see - it could have been the= specific tape I used - and remember 
> that Ferrofluid is a fluid and in fa= ct might have put just enough 
> moisture in that area (even though it was w= iped off after use) to 
> alter things in baking. There are too many variabl= es as I mentioned.

> But as I said - in general - I did have a pretty stron= g feeling that

> in general tapes that were baked did have lower RF. BUT I = dont have 
> any statistics to back this up at all - and it could be that in= 
> certain formulations the mag particles might have been affected in a 
> man= ner that would reduce their field. ON the other hand - I know 
> that heat c= an in fact cause an increase in field strength and allow 
> a transfer to ot= her media by contact - which is the way Sony 
> Sprinter duplicators used to= work - by heating the mother that would 
> then come into contact with blan= k tape and impart the field on the 
> duplicate.
>
> There are really so many variables here - the formulations change 
> batch t= o batch and of course there were so many different 
> formulations and produ= ct types over the years. I am afraid that the 
> only real thing they have i= n common is that they were called "tape".

> Making generalzations is really= dangerous.
>
> I have never been a big fan of baking as I have said over the years 
> and I= have only had to use it rarely - and frequently in those cases 
> because t= here were other problems - like tapes not being properly 
> cured in the fir= st place. I have always felt that there were other 
> ways that just worked = better and were not invasive. Baking is just 
> one tool in the toolbox.
>