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Re: arsclist Pellon and thoughts on baking/Philosophy
Let me weigh in here.
I've seen tapes with severe sticky shed on which surface material pulled off
as it was being slow wound. A bunch of them.
Nothing requiring winding the tape- to pass through pellon, to go past
revolving surface guides, etc., undoes the potential for layer-to-layer
sticking--- except baking. Anything else (except long storage at just above
freezing) allows the rescue process to potentially inflict the physical
damage the process is trying to avoid.
----- Original Message -----
From: Richard L. Hess <lists@xxxxxxxxxxxxxxx>
To: Sarah Stauderman <StaudermanS@xxxxxx>
Cc: <ARSCLIST@xxxxxxxxxxxxxxxx>; <harry_rice@xxxxxxxxx>
Sent: Friday, May 11, 2001 5:30 PM
Subject: Re: arsclist Pellon and thoughts on baking/Philosophy
> I wonder if the baking process is any worse than the tape sitting in an
> aluminum shipping container on the tarmac at LAX in the summer waiting to
> be loaded on the Fed Ex plane--we all are guilty of shipping our master
> tapes by Fed Ex and worse without temperature controls.
> I have heard one horror story of baking--but only one.
> While I am all in favor of doing no harm to original artifacts we also get
> to the question of whether the artifact or the content is the important
> item. Most of the people I'm working with -- and granted they're not the
> Smithsonian -- want the content and could care less about the carrier.
> want the content to sound absolutely as good as it can. Several people
> come to me after horrid transfers and have said can you do anything? I
> agree with Mr. Lindner: go to an expert first not after you've made the
> problem worse.
> I have seen sticky-shed so bad that a reel would not self-unroll. Many of
> the tapes with sticky-shed will leave stuff on the guides, but will unroll
> easily. Some will pull so hard you fear the oxide will be left
> behind...almost like Scotch 111 removable mending tape being pulled off
> What weight Pellon do you suggest? I'd like to try it, but I won't on a
> tape I have to restore--if what I see on tape guides is any indication
> there will be a lot more on the Pellon if it's going to remove all the
> debris that is likely to cause stickiness.
> Besides, the Pellon treatment isn't tested in any scientific way, either.
> It's another process that has been evaluated by empirical test and while
> Ms. Stauderman and Mr. Lindner (both of whom I have great respect for)
> worry about the baking process, I'll stand out here as one voice worrying
> about removing enough material to make the tape non-shedding by a wiping
> process. I know in previous emails Mr. Lindner has said the amount of
> material removed is infinitesimal, from what I've seen on SOME tapes and
> what comes off on the polished guides when I have to wind the tape before
> baking (which I hate to do) I would be amazed that there wouldn't be a
> amount of oxide on the Pellon.
> What I do know is that prior to baking, the tape's oxide surface seems to
> be soft and tacky. After baking it is hard and shiny just like new tape.
> Once long ago I did well in the Chemistry Achievement Tests but never
> pursued it further so you can take this with a grain of salt, but what I
> think I'm seeing in the sticky-shed tapes appears almost to be a state
> change from solid to goo (conceptually, think of ice to slush). From my
> observations it doesn't appear to happen to the surface only, but rather
> appears to be deep within the binder/oxide paste that is placed on the
> I don't have any bad sticky-shed tapes at the moment, but I will look for
> one--or maybe try to make one. Do you think if I leave a reel of 1981
> vintage 456 in my bathroom for a month of showers it will be hydrolized
> enough? I live in LA--I have to do something dramatic to match the climate
> of the Pacific Northwest where my worst sticky-shed examples came from
> have been returned).
> I think we perhaps come from two different worlds. Hopefully, at the
> Smithsonian (and most of VidiPax's other clients) material is stored in at
> least office environments and often special-purpose archival storage
> facilities. Contrast this to 456 kept in a wooden barn on a small island
> off the coast of Vancouver Island. Trees hanging over the barn. No central
> heating only space heaters in some rooms. I've heard of other tapes kept
> against a stone basement wall in lake country. This is the fate of many
> masters for LPs that were made in the 70's and 80's (if they didn't find
> their way into the dumpster). The ones from the small island had
> collectively sold probably 120,000 copies--not huge but respectable. We
> want to do a retrospective CD set.
> Anyway, I spoke at length with Mr. Lindner at the NAB and we're in violent
> agreement that studies should be done to see what the problems are. I
> have a citation, but the 1dB loss at high frequencies due to baking was
> from an Australian study as I understand it.
> I'm not even sure how you do the test to attribute the losses to the
> baking. Couldn't the losses be attributable to the hydrolization? For
> example if a hydrolized tape that has been baked loses 1dB at 20kHz
> compared to a non-hydrolized tape that wasn't baked how would you know if
> it was the baking or the hydrolization. We would know if baking a
> non-hydrolized tape yields the same loss, but it's not conclusive
> <soapbox mode on>
> The following is not really addressed to anyone in particular but to all
> us in general.
> Now let's move on to acidosis or vinegar syndrome (VS) to make a point.
> Kodak Molecular Sieve material is reported to retard deterioration from
> Some 1940's vintage BASF/Agfa/IG Farben Magnetophonband and Scotch 111
> I recently transferred suffered from a vinegar smell but still played
> But for how much longer? How does VS affect tape? What is the timetable
> compared to film? What can slow it? At SOME POINT we will need to make
> decision to copy the material and abandon the current carrier. We've had
> do that with nitrate based film stock. At some point we'll have to make
> that decision with audiotapes. It seems that we may have abandoned
> newsprint too soon in favor of microfilm and I know that archivists and
> librarians are smarting from that one and are being called to task for
> decision, but let's make sure we don't lose assets by inaction. Let's get
> material transferred to a reasonable format before it's too late. Inaction
> may solve some of the problems for us.
> We have funding, staffing, and technological challenges to overcome but we
> have to make a concerted effort to decide how to save this material before
> it's too late. When will it be too late? I can't say. Tomorrow won't
> be...20 years might be for some material.
> One estimate is that there is 50M hours of material in the world to
> transfer (yup- fifty million). Some think that's conservative. Assuming
> time for transferring (and let's not even say "to what") that's 200
> person hours or 100 thousand person years of transferring.
> <soapbox mode off>
> At 04:13 PM 05/11/2001 -0400, Sarah Stauderman wrote:
> >To clarify about Pellon: it is non-woven polyester (fabric), also known
> >as polyester web.
> >One issue that it seems to me is always avoided in discussions about
> >baking is that it has never been tested in a scientific laboratory set up
> >to compare and analyze the effects of baking. There's lots of anecdotal
> >evidence that says that baking is ok and that it works (there's a patent
> >on it, in fact).
> >But, speaking as a conservator, it is simply wrong to use untested
> >treatments on cultural artifacts. At the very least, audio engineers who
> >use baking need to understand what the long-term effects of baking may
> >or explain thoroughly to clients/cultural institutions that baking may
> >result in irrevocable damage to the original artifact. Perhaps baking is
> >the only method to use on tapes with heavy sticky-shed resulting from
> >hydrolysis. If this is the case, we still need documented evidence of
> >efficacy and implications.
> >Meanwhile, I participated in a study of cleaning videotapes (3/4" u-matic
> >was the format, and the brand was Ampex, and BASF) using non-woven
> >polyester. This report was given at the American Institute for
> >Conservation annual meeting in June 1999. The scientist, Mary Baker,
> >examined the surfaces of tapes using FTIR. There was no chemical change
> >before and after cleaning. Unfortunately, the tape sample was too small
> >and the means to study a change in picture quality was not available. We
> >also did not get the enormous amount of residue on the cleaning webbing
> >that Mr. Hess has observed. In the end, we felt that no chemical change
> >was a good indicator of the utility of cleaning with polyester webbing,
> >but that it warranted additional study.
> >Incidentally, this study was carried out at the Smithsonian Center for
> >Materials Research and Education, which is slated to be eliminated from
> >the Smithsonian in December 2001. The cleaning, I should also mention,
> >was carried out at VidiPax's New York lab. I wish that there was a
> >concerted effort to characterize treatment activities and their
> >implications by audio restorers and video restorers. Groups like ARSC
> >AMIA need to work with SMPTE and standards organizations to do this
> >research. If I had a lab, I would.
> >Opposed to baking until it's proven otherwise, or as a very last resort,
> >remain, wishing you all best luck with your materials,
> >Sarah Stauderman
> >Sarah Stauderman
> >Preservation Manager
> >Smithsonian Institution Archives
> >202-357-1421 x 56
> > >>> lists@xxxxxxxxxxxxxxx 05/11/01 12:20PM >>>
> >pellon (a thin stiff white fabric found in craft and fabric stores) (as
> >found on the Web)...
> >To be totally fair, Jim Lindner is a much more experienced person than I
> >dealing with tape problems, although I'll confess to being resourceful
> >obtaining good results. We philosophically disagree on the superiority of
> >the two processes:
> >Lindner is horrified at the thought of baking. He tries to avoid it at
> >I, on the other hand, am greatly concerned about wiping tapes until all
> >goo is off because I see the stuff on the wipes as containing oxide in
> >now-scrambled orientations that used to contain the signal I'm trying to
> >get off the tape.
> >In one double-blind test, Lindner found that about 60% of the listeners
> >(not much above the 50% random chance) (if I correctly recall his telling
> >me on the noisy floor of the recent NAB show) found some deficiencies in
> >the low frequencies of baked tapes as compared with wiped tapes. Now, I
> >don't know how you can do double-blind tests of this with precisely the
> >same material without copying and the copying process itself (especially
> >15 and even more so at 30 ips) introduces substantial low frequency
> >anomalies due to "head bump" phenomena. So I am not sure if Lindner's
> >reported double blind test is hearing the restoration process or some
> >anomaly in the copying process.
> >As to baking, there have been some reports of a 1dB loss of the highest
> >frequencies. I have baked one set of tapes twice and on the second baking
> >reproduced them on a superior machine as opposed to the one after the
> >baking. The tapes sounded better after the second baking on the superior
> >machine, so the machine difference is more than the difference in
> >baking--an IMPORTANT point to remember.
> >My comparison of machines was between a ReVox A77 and a Sony APR5003V. In
> >my mind, the APR is one of the five best machines ever made, the others
> >being the Studer A820, the Ampex ATR-100, the Ampex MR-70 (if you want
> >tube), and the Nagra T. The ReVox A77 was a competent low-end machine
> >worked as well as many other machines in its price range. If you've got
> >high-end tapes, they deserved to be digitized from a high-end machine.
> >More than you asked...but it's all related!
> >At 10:54 AM 05/11/2001 -0400, harry_rice@xxxxxxxxx wrote:
> > >Richard:
> > >
> > >What are Pellon wipes?
> > >
> > >Harry Rice
> > >Berea College
> > ______
> > >Subject: Fwd: BOUNCE arsclist@xxxxxxxxxxxxxxxxx: Non-member sub
> > >From: <ARSCLIST@xxxxxxxxxxxxxxxx> at berlink
> > >Date: 5/11/2001 9:20 AM
> > >
> > >
> > > >Date: Thu, 10 May 2001 12:36:56 -0700
> > > >To: Language Laboratories and Archives <language-labs@xxxxxxxxxxxx>
> > > >From: "Richard L. Hess" <richard@xxxxxxxxxxxxxxx>
> > > >Subject: Re: arsclist sticky shed
> > > >Cc: ARSCLIST@xxxxxxxxxxxxxxxx
> > > >
> > > >Hi, Barbara,
> > > >
> > > >There are resources on my Web page at
> > > >I think at least some of these people deal with sticky shed syndrome.
> > > >VidiPax does it by wiping with Pellon wipes, most of the rest of us
> > > >I've had good results with a whole heap'o'tapes but it's never
> > > >and while we all take the utmost care we cannot be held liable for
> > > >the master--I think that's pretty standard.
> > > >
> > > >If it's only one reel I could look at it for you. If it's much more
> > > >that, I don't have the time. $100 hour is close to the going rate (I
> > > >VidiPax charges $95). That's per hour of studio time not per running
> > > >of program. My general estimate is that it takes from 4-10x depending
> > > >what needs to be done and how good you want it. The 6x is typically
> > > >finessing individual dropouts--you've got to find them which means
> > > >listening and watching.
> > > >
> > > >What is the tape format, what is the tape brand, how long is it?
> > What's on
> > > >it? what do you want to do with the content?
> > > >
> > > >I see you're from the language labs. If it's just word and it's a
> > > >continuous tape (no splices) it might not even take 4x. If it is
> > with
> > > >lots of splices for CD re-release, It generally approaches the 10x
> > > >
> > > >I've done reel tapes as early as 1947 with some Bing Crosby excerpts
> > > >them (no sticky shed, but lots of problems) but most of my current
> > > >centered on folk music from the 70's and 80's when sticky-shed was at
> > > >worst.
> > > >
> > > >Good luck finding someone to do it!
> > > >
> > > >Cheers,
> > > >
> > > >Richardy copying process itself (especially
> > > >
> > > >
> > > >At 01:12 PM 05/10/2001 -0500, Language Laboratories and Archives
> > > > >Hi, We just had a case of sticky shed, and the company we dealt
> > many
> > > > >years ago is no longer in business. Who are you all working with?
> > > > >
> > > > >Barbara Need
> > > > >UChicago--Language Labs
> > > > >-
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