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ARSCLIST  May 2007

ARSCLIST May 2007

Subject:

Re: 'New' solution for stickey shed

From:

Steven Smolian <[log in to unmask]>

Reply-To:

Association for Recorded Sound Discussion List <[log in to unmask]>

Date:

Mon, 14 May 2007 17:08:01 -0400

Content-Type:

text/plain

Parts/Attachments:

Parts/Attachments

text/plain (247 lines)

Nonetheless, I wouldn't dismiss this out-of-hand. It's a clue to another
approach. There is surely a chemical or compound in the product that bears
isolating and testing.

Steve Smolian

----- Original Message -----
From: "Jim Lindner" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Monday, May 14, 2007 3:47 PM
Subject: Re: [ARSCLIST] 'New' solution for stickey shed


>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: [log in to unmask]
>
> Media Matters LLC.
> SAMMA Systems LLC.
> 450 West 31st Street 4th Floor
> New York, N.Y. 10001
>
> eFax (646) 349-4475
> Mobile: (917) 945-2662
> Office: (212) 268-5528
>
> 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
> 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: [log in to unmask]
>> 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.
>
>
> --
> No virus found in this incoming message.
> Checked by AVG Free Edition. Version: 7.5.467 / Virus Database:
> 269.7.0/803 - Release Date: 5/13/2007 12:17 PM
>
>

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