Jim,
Let me add a positive retort here, (before the waves of negative ones
begin)....
I agree with you 100% that most in the archival world are focusing on
the wrong issues, or maybe have been lingering on the same problems for
too long. The issue in my mind is scale because most in the archival
industry are seeing a box, or room full of tapes, and have not had the
opportunity to see over 1 million assets in a single location, nor
contemplated what to do with them.
As the Director of Archives for EMI, I look at all the assets under my
control (over 1 million, just in North America), and think to myself:
"How much sense does it make to preserve these assets in these formats,
when the machines, engineer knowledge base, and media itself if
deteriorating."
Once you scale out and see the big picture, you start to see the REALLY
big problem. If we (the archival industry) can't get a digitization
schema to be cost effective, we simply won't get the funds to digitize.
Worse, if someone outside the archival industry, gets "their" plans in
motion, you can rest assure that it will not be done anywhere near
correct.
As you know, the barriers to digital migration are also far more complex
than the real time transfer that it involves (even if we're using SAMMA
"robots".) Digital files take error checking, redundant copies, naming
conventions, metadata collection, metadata hierarchy standards, etc.
Figuring all this out UP FRONT, makes for a daunting task that I will
venture to say, takes a completely different skill/mind set than analog.
Unfortunately people don't change, and no matter how many positive
reasons you give to migrate, those entrenched in analog will want to
stay there.
I believe there should be communal, parallel thinking in regards to mass
digitization strategies, metadata collection and so forth. I am aware of
library groups focusing specifically on metadata, but I have my own
concern with their focus, and priorities in regards to collecting
metadata on A/V assets.
I'm available for dialog on this topic, and I would hope that others on
the list may open minded enough as well.
Don Andes
Director of Archives
EMI Music
-----Original Message-----
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
eFax (646) 349-4475
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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.
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SAMMA Systems provides tools and products that implement and optimize
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and access practices.
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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