I read the postings on the Tape Ops page and have to agree with Peter and
Richrad that some of the "statements of fact" which are claimed are not my
experience either - or said in another way - there have been many tapes
that are in a state that differ very substantially with some of the all
encompassing statements - such as "there has never been a documented case
of a non-backcoated tape having SSS". Sorry - I have seen a bunch. It may
also be somewhat of a definition issue as well. Is it SSS or is it
something else - without proper chemistry testing it is hard to tell, and
some of those tests are destructive anyway..... but that does not seem to
stop anyone from coming up with alternative treatment approaches. There is
also a patent that has been granted to someone who claims that removing
the back-coating will similarly cure tapes - and the patent has some real
questionable statements as well. But there you have it. The biggest
mystery to me is why Ampex - a company that HAS a patent on baking and
one that has a history of vigorously protecting its IP has never done
anything to protect its process. But that horse is long out of the barn -
and I think it is in some ways beside the point.
Now what I am about to say may be a bit controversial in these hallowed
ARSC halls - virtual halls I suppose - but I will speak out and hope to
not be accosted - or at least to not be accosted with too much vitriol. I
will promise to go back to lurking after this little squeak. (that was a
joke)....
So here goes...
In some ways I personally feel that I have "moved on" from this entire
discussion - I don't think that the point any longer is to "cure" the
tape forever so that it will be OK for analog playback. I think that a
shorter term more pragmatic approach - which simply said is "get it off
the bad stock" is a better bet. I think that this is particularly true in
Audio - unless that particular reel has some artifactual value (i.e. it
was owned by someone famous and is the only extant recording of its
type) - then the point is to save the content in a fashion that is as
clean as possible - and move on. I don't see that there will be a surfeit
of operable 2" Studer machines 100 years from now to really deal with the
legacy that is purported to be saved by saving the original carrier - and
at some point we need to be comfortable enough to say - yeah - we have
captured the content extremely well - and well enough is likely to be
well enough.... forever... because at some point it has to be. The scale
of the problem is SO large that any other philosophy is simply
unworkable, as a practical matter.
We have been doing some market research into the number of tapes that
really are out there - and at the moment I am talking about Video tapes.
I was always suspicious about the UNESCO claim of 200 million carriers. I
just did not believe it - it did not make sense to me. Doing some real
market research has provided some numbers that frankly stun me - and I
have been in this for a LONG time - and still I am shocked. Here is one.
Disney - has over 6 million tapes. One company. 6 Million. Now I have no
idea how many audio tapes they have - but it is the scale that dwarfs the
mind. MTV 1.5 million - that is MILLION. One vendor alone - I can't say
who - sold more then 300 MILLION Umatic carriers - and that was just in
Europe. VHS tapes - more then 300 million blank tapes a year (not
pre-recorded tapes, blank ones) for at least 15 years. I could go on -
but the point is this. As a field - of people who care about the
preservation of cultural heritage.... we need to move on and come up with
better and faster and cheaper ways to transfer these tapes - because if
we don't - it is game over for the huge and overwhelming percentage of
them. Sure - with proper storage we can extend the life- but to what end?
What are we waiting for - other then retirement and to pass them on to
the next person. Are we expecting a new generation of really cheap analog
mass migration systems to come out of the mist and magically play back
the tapes on a yet undefined new format to save for posterity - or is
there another reality - one decidedly less sexy and grim - which is that
there is not likely to be much work in these areas because manufacturers
are looking elsewhere - and what we are saving them for - is for being
thrown out - by someone else - but being thrown out nevertheless because
at some point - it truly is game over -because there isnt much gear and
there is certainly less time.
Call this a plaintive cry to the field to stop working on stop-gap
thinking and work toward a more comprehensive approach to the saving of
all of this content. Painting these tapes with NUFinish is really besides
the point. The point is that Analog is over, and the sooner we get to the
really hard job of developing cost effective mass migration techniques to
save the vast corpus the better. Now some of you may say my statements
are self-serving - and I will fully and freely admit that I have worked
very hard to develop these techniques and have worked to commercialize
them - but I do not see any other way to save the content, and I have
been successful in driving the price lower and lower using new
technology. But - we are just one company - and we need help - yes we
need competition because THE point is to save the content - and to do
that - we need to be thinking differently. The problem is not how do we
stop a single troublesome tape from squeaking - the problem is how do we
migrate the millions of recordings fast enough and cost effective enough
and good enough - for the future. I don't see much of that going on - and
it deeply concerns me. We need more people thinking this way - I want to
read about techniques that can be applied to thousands of tapes that will
allow fast and cost effective transfer. This is something that we ALL
need to work on - the collective brains and expertise on this list and
others needs to focus - we can differ in our individual philosophies but
please let us not get so distracted by esoteric un- scaleable treatments,
that we forget the whole point. Which is - to save the stuff. I am sad to
say that collectively - all of us (including me)- have not been doing a
very good job - we need to do MUCH better. We need to work together - and
smarter. The risk of loss is simply too great.
Ok - I am done - and I am running,,,,
Jim Lindner
Email: jim@xxxxxxxxxxxxxxxxx
Media Matters LLC.
SAMMA Systems LLC.
450 West 31st Street 4th Floor
New York, N.Y. 10001
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www.media-matters.net
Media Matters LLC. is a technical consultancy specializing in archival
audio and video material. We provide advice and analysis, to media
archives that apply the beneficial advances in technology to collection
management.
www.sammasystems.com
SAMMA Systems provides tools and products that implement and optimize the
advances in modern technology with established media preservation and
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On May 14, 2007, at 1:59 PM, Richard L. Hess wrote:
At 07:48 AM 2007-05-14, Tom Fine wrote:
Hi Konrad:
Some of what this guy says is simply not right about sticky-shed. I
can't comment on his "cure". I'll stick with baking tapes, which is
proven to work.
I'm hoping Richard Hess posts a long missive on this one. With this
topic well-addressed many other places, I wonder why so much mythology
persists?
Hello, Tom, Konrad,
Peter Brothers has posted an excellent hypothesis as to why the chemical
technique may work. If we consider that the short (broken) chains which
is the lower molecular weight, sticky stuff ends up partially adsorbing
to the magnetic particles when water is driven out, then this mystery
chemical could also be a water "magnet" and can pull the water out of
the coating allowing sites for the short chains to adsorb. This is
consistent with the baking process.
We certainly have seen tapes suffering from binder hydrolysis -- what
I'm starting to call "Soft Binder Syndrome" (SBS). With non- back-coated
tapes there is a large population (not 100%, but close) that do not
respond to baking. These are the SBS without SSS tapes. We used to call
them "loss of lubricant" (LoL) until we found out there was still ample
lubricant in the tapes.
What we are seeing with the non-back-coated tapes that have SBS (and
squeal) is that they are in a rubbery phase at room temperature because
the breakdown of the polymers has caused the temperature at which the
surface turns from smooth to rubbery (called the GLASS TRANSITION
TEMPERATURE or Tg) has fallen to below room temperature. What we do in
these cases is play the tapes with the tape and the player below the
current Tg of the tape.
Measuring Tg is not easy -- you need to measure the Youngs Modulus of
the Coating (alone not on the basefilm) at various temperatures and from
that plot you can extract the Tg.
It all comes down to the tapes decaying and for all of the
polyester-polyurethane tapes it appears that moisture is the catalyst
for the breakdown -- hence as Peter says, it's all hydroysis.
Incubation/baking appears to cause enough movement in the tape pack to
break the layer-to-layer bonds that form under pressure (especially near
the hub) that causes pinning and pullouts. I have found that slow (1.88
in/s) playback of the tape also helps in that regard.
I think our goal here is to use reliable, tested processes and digitize
the content. I spent a substantial amount of effort working on tapes
that squealed and did not respond to baking. My cold playing technique
(which I encourage all of you to try and respond back) should, in
theory, work with SSS tape as well as SBS (and I suggest that SSS is a
subset of SBS), but the massive amounts of debris generated by the
backcoat/magcoat combination overwhelms the capability of cold playback
(at least right now) and at pro play speeds, pullout is exacerbated due
to the bonding between backcoat and magcoat.
I do not think we've yet seen a documented case of LoL so thankfully
that myth is being put to bed. We used to think the squealing Sony
PR-150 and 3M 175 was LoL, but we now see that it is SBS. By the way,
the Tg of one sample of 175 was about +8C or about 46F.
Keeping polyester polyurethane tapes dry (<40% RH) is a good way to keep
them feeling OK. I had a non-backcoated tape of this type that had been
peaking at 75% RH in storage "heal" after three months storage at about
40% RH.
By the way, it is approximately a minute:day relationship between
thermal and moisture equilibrium--or at least that's a convenient way to
think of it. In other words if a tape takes 90 minutes to reach thermal
equilibrium throughout the pack, then it takes 90 days to reach moisture
equilibrium. This is based on work with 1- inch tapes so 1/4-inch tapes
might not be as bad, but it seems to match my experience.
My AES paper cites the reference for that.
In general, I am less happy with a chemical approach than a
physical/state approach (within limits) to the SBS/SSS problem as there
is a great chance of unknown, long-term damage from any chemical
approach. With that said, I have tried approaches to SBS based on the
LoL hypothesis and they were abysmal failures.
Konrad: we did have a belated success in your neck of the woods with
playing a tape in a fridge. Paul or Mike have the details. I think it
needed 48 hours of cold soak before it played.
Cheers,
Richard
Richard L. Hess email: richard@xxxxxxxxxxxxxxx
Aurora, Ontario, Canada (905) 713 6733 1-877-TAPE-FIX
Detailed contact information: http://www.richardhess.com/tape/
contact.htm
Quality tape transfers -- even from hard-to-play tapes.
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