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ARSCLIST  March 2015

ARSCLIST March 2015

Subject:

Re: Distressing data point for upcoming ARSC tape playback workshop

From:

Tom Fine <[log in to unmask]>

Reply-To:

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

Date:

Sun, 1 Mar 2015 14:35:41 -0500

Content-Type:

text/plain

Parts/Attachments:

Parts/Attachments

text/plain (297 lines)

Hi John:

My experience is that not all acetate-backed audio tape develops vinegar syndrome. I have only run 
across it with Kodak tape (in all cases) and Scotch 111 and related formulations (in many but not 
all cases). Audiotape (Audio Devices) is a different story. I have no idea why. I've had access to 
and used 1950s vintage Audiotape acetate-backed (I'm assuming acetate because it's see-through when 
held sideways to the light -- and because some boxes say "acetate backing" in the descriptor text) 
since my youth and my first reel to reel machine. In all that time, including recent work with 1/2" 
Audiotape reels, I've only encountered a handful of vinegar-smelling or warped/curled tapes. Again, 
I have no idea why this is. Audiofilm, also made by Audio Devices, has more often than not developed 
vinegar syndrome in the experiences I've had with it (a few cases of 35mm full-coat returned from a 
warehouse and stored in my parents basement from the 1980s into the 2000's).

What I do know about acetate-backed Audiotape is that it dries out and gets brittle. I assume low 
moisture and humidity speeds up this process. The only way temperature should matter is in relation 
to relative humidity, except for the fact that excessive heat causes edge-warp and curl, in my 
experience (which is why acetate media should NEVER be baked). I'm not advocating anything beyond 
normal ambient-room conditions as far as temperature and humidity. By "hotter and wetter," I mean 
not the freezing bone-dry conditions used for nitrate films and now commonly used for sticky-shed 
tapes.

It's worth noting, by the way, that almost all of the Mercury (and RCA and Columbia) acetate tapes 
were kept in room-temperature warehouses and company storage vaults for decades. Come the 1990s, 
many of the tapes (and almost all of the Mercury tapes) played just fine and very good-sounding 
reissue CDs were made. Then, the companies got more serious about vaults because they had such a 
problem with sticky-shed. They lumped all the tapes together, concetrating on cold/dry vaults. The 
sticky-shed tapes still need baking and the acetate tapes now are drying out.

My fear, based on having seen this with acetate tapes stored in hot and mostly dry attics, is that 
further storage under those super-dry conditions will make the tapes too brittle to move through a 
tape transport without snapping and splitting, or having the oxide drop off because the binding 
material has dried out. I'm surprised this hasn't happened with full-coast magnetic film stored in 
too dry conditions too long. Because the film base is so thick, I would think these things just 
self-shred in the typical film transport, but maybe the thicker base provides enough strength to 
withstand being brittle?

As I said above, if cold helps with vinegar syndrome, then keep them cold (it's worth noting that I 
just examined a bunch of tapes kept in a cold/dry vault since the 1980s and sure enough the two old 
Kodak acetate tapes in teh collection were warped/shrunken and stunk of vinegar; the Scotch 111 
reels were fine, so maybe the cold staved off vinegar syndrome for them). I'm more concerned about 
over-dry not being necessary for acetate audio tapes and making them unplayable brittle.

-- Tom Fine

----- Original Message ----- 
From: "John Schroth" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Sunday, March 01, 2015 1:15 PM
Subject: Re: [ARSCLIST] Distressing data point for upcoming ARSC tape playback workshop


> This is where AMIA and ARSC can benefit from one another.
>
> The members of AMIA have been dealing with Vinegar Syndrome (VS) for many more years than audio 
> people with acetate based audio tape (acetate based motion picture film has been around since the 
> late 1920's / early 1930's). There are storage recommendations and standards for acetate based 
> motion picture film that have been published many times and tools one can easily find to help 
> identify even minute beginnings of VS, such as AD strips from the Image Permanence Institute at 
> RIT: https://www.imagepermanenceinstitute.org/imaging/ad-strips
>
> From my humble experience, all acetate based media slowly breaks down. Without the ability for 
> acetate based media to "gas-off" so to speak, acidic acid leaches out of the acetate base and the 
> vapors are contained with the media. VS begins and the vapors become more and more dense. As the 
> density increases, the acetate breaks down and VS increases logarithmically. You see this all the 
> time with motion picture films stored on old metal reels in old metal tins that do not allow the 
> film to breathe. The only time I have found acetate based audio tape with VS is with the same 
> storage parameters - the reel was placed in a protective plastic bag, then in the standard 
> cardboard box, or protective air tight plastic audio box or the reels were placed together in an 
> air tight plastic container. The audio tape could not breathe or gas-off and VS began. From my 
> understanding, VS breakdown can be halted (but not reversed) by using cold storage methods. Again, 
> I am not an expert but it is my understanding that you can halt VS at storage temps just above 
> freezing, freezing is not required.
>
> Motion picture film is frozen all the time. The key is how the film is prepped and packed prior. 
> Also how the film is unpacked and re-acclimatized to the environment prior to working with the 
> film again in standard room conditions. Although the base is the same, there is obviously a 
> difference between acetate based motion picture film and audiotape because of the medium that is 
> on the acetate carrier. It is possible that the binder in acetate based audiotape is less 
> forgiving than motion picture film emulsion when frozen - but again, another good question that 
> may have some good answers from AMIA, as these folks work with and store, a lot of full coat and 
> mag stripe acetate based audio recordings which are surrogates to the visual motion picture film.
>
> Tom, I know you're relatively speaking, but I would not want someone inexperienced reading this 
> post thinking warmer/wetter is a better storage condition for acetate based media. Warmer and 
> wetter than freezing - yes, but the warmer and wetter the storage conditions above freezing, 
> combined with the inability for the medium to gas-off, the better the chance for VS to begin with 
> acetate based media. I have clients on almost a weekly basis bring in motion picture film to 
> transfer, who thought that the home basement or below ground office storage was the best place to 
> store their movie film. Yes, the temps are slightly cooler than the rest of the building, but RH 
> is definitely higher in a room "below ground level". This is where I see the bulk of the VS movie 
> film coming in - when the client has stored the film in a basement in a metal tin. I rarely get 
> film with VS that has come from an air conditioned house or business where the film has been 
> stored on the first or second floor. This tells me that VS is triggered more by humidity than 
> temp.
>
> On the topic of sticky shed, folks from AMIA also deal with a LOT of sticky shed. I'm now baking 
> almost as many videotapes as I do audiotapes. And the videotapes, like the audiotapes that require 
> baking, are the professional back-coated tapes. Most often they are open reel videotape formats 
> although I see more and more 3/4" U-Matic tapes and other older format cassette tapes that require 
> baking. I'm not sure myself if cooler less humid storage conditions help to mitigate sticky shed. 
> It's interesting because a client came to me three weeks ago with reel to reel tapes that he 
> claimed were properly stored in a climate controlled vault. They were 3M/Scotch 206 audiotapes. 
> They had the typical sticky shed and required baking even with the climate controlled storage. I'm 
> not sure what freeze drying would do to a tape, but it might be interesting to see if this might 
> be an alternative to baking. I've talked to several companies in the past that specialize in 
> disaster relief. Their standard practice is to freeze dry everything (in these cases it is 
> contents from an office building or home and AV media just happened to be caught up in the mix). 
> I'm wondering what the effects were on the media?
>
> For what it's worth...
>
> John Schroth
>
>
> On 3/1/2015 11:20 AM, Tom Fine wrote:
>> Hi Richard:
>>
>> I worry that below-freezing storage of acetate media may freeze-dry it out and make it so brittle 
>> that eventually it has no plasticity. If super-cold/super-dry storage staves off severe 
>> sticky-shed and it can be proven to really do that over time, then I would say it's the way to go 
>> on that quantity of polyester-backed tape prone to sticky-shed (I've heard estimates of 25-33% of 
>> tapes in vaults; I'd say it's probably closer to 25% given the long history of tape recording 
>> before polyester back-coated tapes, the fact that not all polyester back-coated tapes develop 
>> sticky-shed, and the fact that there is no consistent data showing that "post-sticky-shed" 
>> formulations didn't solve the problem, and tape was used for quite a while after the problem was 
>> said to be solved).
>>
>> It may well be that sticky-shed tapes need to be stored in a special way, by themselves. Much 
>> like nitrate films (maybe even in the same vaults, because I think they both need the same 
>> storage conditions). Everything else should probably be stored in somewhat warmer, somewhat 
>> wetter conditions. But, we're all just speculating until there's more reliable science on this. I 
>> do speak from decades of experience owning and using old acetate tapes, however.
>>
>> -- Tom Fine
>>
>> ----- Original Message ----- From: "Richard L. Hess" <[log in to unmask]>
>> To: <[log in to unmask]>
>> Sent: Sunday, March 01, 2015 10:58 AM
>> Subject: Re: [ARSCLIST] Distressing data point for upcoming ARSC tape playback workshop
>>
>>
>>> Hello, Tom,
>>>
>>> This is a wonderful post. Without actually stating this, you highlight the challenge we all face 
>>> by NOT having adequate scientific analytical backup to help direct the care and physical 
>>> restoration of various media. Of course, after PrestoSpace found that the same manufacturer tape 
>>> type number could apparently represent four different formulations over time, we learned that 
>>> the project is daunting if it is doable at all with any accuracy in an affordable manner.
>>>
>>> I have a couple of addenda to help round out this picture. I agree that more work needs to be 
>>> undertaken and it is getting late to do it. I have spoken of your concerns whenever I thought it 
>>> would make an impact as I know this is not the first time you have semi-publicly stated them 
>>> here on ARSCList.
>>>
>>> (1) I believe, at least here at Library/Archives Canada, that FILM is kept cool and dry but well 
>>> BELOW FREEZING (of water i.e. WELL BELOW 0°C / 32°F. If you want an idea about how well below, 
>>> my GUESS is -20°C / 4°F. I also believe that this level of cold does help stave off "vinegar 
>>> syndrome."
>>>
>>> (2) When I had an informal meeting with the good folks at the Library of Congress (I think it 
>>> was late June 2012), I started talking about the extended baking times several of us have 
>>> independently reported and they claim that is not needed in their work. I confirmed that they 
>>> are working with "captive" tapes from their vaults. I do think this is a clue that cold/dry 
>>> storage is reducing the severity of sticky shed syndrome.
>>>
>>> I am blind copying a few people to make certain this information gets out there.
>>>
>>> Thanks again!
>>>
>>> Cheers,
>>>
>>> Richard
>>>
>>> On 2015-03-01 9:46 AM, Tom Fine ([log in to unmask]) wrote:
>>>> I am right now working with tapes from 1959 and 1961, 3-track 1/2"
>>>> tapes, with splices "replaced" in 1971 (according to documentation on
>>>> the boxes) and, in the case of 4 reels, splices cleaned and/or replaced
>>>> in the early 1990s. Alas, every splice so far has needed new cleaning
>>>> with Naptha and many of them -- even those cleaned and successfully
>>>> played in the 1990s -- have required full replacement.
>>>>
>>>> The replacement splicing tape put on in the 1990s has proven mostly
>>>> stable but there has been some ooze and stiction around some splices. I
>>>> tend to believe that is leftover ooze from non-complete cleaning of the
>>>> original splices before replacement, but it could be new ooze over the
>>>> past 20 years.
>>>>
>>>> Bottom line is that there seems to be no "permanent" splicing tape, it
>>>> all seems to ooze and/or dry out over time.
>>>>
>>>> Another distressing datapoint ... This is the second batch of late 1950s
>>>> Audiotape acetate-backed tape I'm dealing with that has become very
>>>> brittle, like most of the plasticity has dried out of the backing. I
>>>> suspect this is made worse by over-dry storage conditions intended to
>>>> somehow "prevent" or "mitigate" sticky-shed in later tapes (and remember
>>>> that there is no proof that dry storage does either). I wish some
>>>> scientists would do some chemistry on acetate tapes and come up with
>>>> better storage recommendations. There are millions of acetate tapes and
>>>> films being stored under the same "keep it super-dry and cold" mandates
>>>> that are imposed on polyester media (and these conditions DON'T stave
>>>> off sticky-shed and DON'T make sticky tapes play longer after baking --
>>>> all credible research and experience so far shows that ALL tapes prone
>>>> to sticky-shed go sticky on their own, that baking allows playback, and
>>>> that ALL sticky-shed tapes go back sticky a certain time length after
>>>> baking; the only exceptions might be -- still not widely tried or proven
>>>> -- the Richardson method of chemically removing the back-coating).
>>>>
>>>> Incredibly, these old tapes still sound damn good on playback, and are
>>>> able to move through a tape transport correctly after the splices are
>>>> cleaned and repaired. I don't know if this will be the case at some
>>>> future date. Luckily, these tapes I'm working with are backed by funding
>>>> for Plangent Process high-resolution transfers and defluttering, so the
>>>> resulting digital assets will be very high quality.
>>>>
>>>> My recommendations, based on this experience:
>>>>
>>>> 1. I've now cleaned enough gooey splices with Naptha to be convinced
>>>> that it is effective and safe for this job.Note that many hardware
>>>> stores carry a can or two or no Naptha at all. It doesn't seem to be
>>>> widely used by professional painters anymore.
>>>>
>>>> 2. It's been helpful to carefully detach the reel flanges -- while the
>>>> tape end is taped down to the adjoining layers and the reel is not
>>>> loose-wound -- and carefully (on a flat surface) clean all visible
>>>> splice ooze (bubbles and chunks of white goo) with Naptha. I put the
>>>> flange back on and flip the reel over very carefully, then do the same
>>>> on the other side. Sometimes -- not always -- this mitigates stiction
>>>> between layers around the splice, preventing even slight oxide damage on
>>>> the edges.
>>>>
>>>> 3. It is important to inspect the layers before and after the splice,
>>>> and clean all residule goo off both sides of the tape.
>>>>
>>>> 4. Very gently deal with the splice itself. It can sometimes be gently
>>>> coaxed up intact -- this happens about 50% of the time with original
>>>> splices on these tapes. When that happens, clean the splice edges and
>>>> center in particular, this is where the ooze will be. When the splice
>>>> separates, I put a good dab of Naptha on the side stuck to the
>>>> tape-pack, cleaning especially the center of the splice. Almost always,
>>>> a gentle coax with the Q-tip with them lift the splice up so it can be
>>>> repaired. When this doesn't happen, I used a chopstick that I whittled
>>>> down to a blunt but pronounced "shovel" point. No splice points mangled
>>>> so far with this. I then clean both sides of the splice, both sides of
>>>> the tape, with a good dose of Naptha. By the way, change Q-tips
>>>> regularly because the accumulated sticky ooze stays on the Q-Tip after
>>>> the Naptha evaporates. Then I repair the splice (use a high-quality, non
>>>> worn-out splicing block, which isn't always to acquire these days). I
>>>> use early 2000's vintage white-colored semi-clear splicing tape. I don't
>>>> at all like this newest thicker blue-colored splicing tape (which seems
>>>> to be the only option these days). Luckily, I have a large store of
>>>> old-style splicing tape.
>>>>
>>>> 5. When playback and transfer is complete, make sure to attach the end
>>>> of the reel to the adjoining tape layer (if it's stored on a hub) or to
>>>> the reel flange with NEW and EFFECTIVELY STICKY tape. An enemy of old
>>>> tapes, especially acetate tapes, is storage under loose-wind conditions.
>>>> The acetate expands, contracts and sometimes gets vinegar syndrome. If
>>>> it is stored tight-wound with the end taped down, it is less likely to
>>>> get edge-warp.
>>>>
>>>> 6. Under ideal archival conditions, without tight production deadlines
>>>> and with unlimited funding, I would say replace all old splices as SOP.
>>>> Under real conditions, this is not always possible. Because of that,
>>>> expect to go through this same procedure again if the tape is played
>>>> again in the future. And, given my experience with 1990s splices, I'm
>>>> not sure that modern splicing tape is any better about eventually oozing
>>>> glue or drying out.
>>>>
>>>> 7. This probably goes without saying, but demagnetize the tape path, all
>>>> metal tools, and work on the splice repair on a non-magentic surface.
>>>>
>>>> 8. It also probably goes without saying, but use Naptha in a
>>>> well-ventilated area. John Chester turned me onto putting in a little
>>>> squeeze-bottle with a needle tip and then squeezing a few drops onto a
>>>> Q-Tip rather than having an open container and dipping Q-Tips into that.
>>>> This method really keeps the fumes to a minimum in a normal-sized room.
>>>> I keep a low-speed fan blowing air across the tape transport to move
>>>> what fumes do escape away from my face.
>>>>
>>>> -- Tom Fine
>>>>
>>> -- 
>>> Richard L. Hess                   email: [log in to unmask]
>>> Aurora, Ontario, Canada                             647 479 2800
>>> http://www.richardhess.com/tape/contact.htm
>>> Quality tape transfers -- even from hard-to-play tapes.
>>>
>>>
>>
>
>
> ---
> This email is free from viruses and malware because avast! Antivirus protection is active.
> http://www.avast.com
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