Vinegar Syndrome: A warning for cel collectors

For the n00bs of cel collecting and production art . . . and for some of us old-timers, too. Post your questions on anything that puzzles you.
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sensei
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Vinegar Syndrome: A warning for cel collectors

Post by sensei »

I’d like to give wider notice to a problem that could potentially affect many cel collectors, especially those who are interested in pre-1990s anime. The issue is that the medium used for the manufacture of cels is chemically unstable, and has the tendency to break down over time. The chemical name for the plastic used for cels is cellulose acetate. This material replaced the older matrix for flexible film stock, which was cellulose dinitrate. This, in turn, replaced celluloid proper, which was too stiff and too unstable to use for most purposes. All are produced by treating the natural plant product cellulose with some kind of acid, changing its chemical structure and allowing it to be melted and then turned into transparent sheets for use in photographic film, microfilm/microfiche, or, as we have come to know, animation “cels.”

All of these materials, a variety of online sources confirm, have the odd property of remaining stable for long periods of time, then rapidly deteriorating in a way that not only destroys the images printed or painted on them, but also the materials stored in their vicinity. This is because the most serious aspect of the reaction is the release of the acid used to treat the cellulose. That’s nitric acid in the case of nitrate film/cels, and acetic acid (aka “vinegar”) in the case of acetate-based film/cels. Once the reaction begins, the free acid causes the molecules it contacts to break down, releasing more acid. This can take a long time to occur in a way that is detectable, as the reaction typically occurs inside the cel sheet, and only gradually travels to its surfaces. When this happens, the first symptom is a distinct chemical smell that resembles strong vinegar.

The process, once it starts, is irreversible. Worse, it is contagious, affecting cels that are stored with it or near it. The reaction can damage and penetrate cel bags and contaminate paper sheets, such as production backgrounds or the black “acid-free” sheets used in the pockets of Itoya portfolios.

I received two descriptions of “worst-case scenarios” recently. Neither collector wished to be identified, and so I’ve not given any information that would identify the cel or series. However, even though one came from a 1977 series and the other from a 1998 series, the events both persons described were essentially the same.

Collector 1 bought the cel from a respected seller on a Japanese auction site. When it arrived, the cel appeared to be in good condition, but the douga that had come in the same bag had a strong chemical smell. The collector let both air out thoroughly, then gave the cel a new bag and stored it normally in an Itoya cel book. The douga, which continued to have the smell, was stored in a different place.

Five years later the collector noticed that the chemical smell had come back in the room where the cels were stored. The culprit was the cel. As the collector described it, both the cel bag and cel were wrinkled, and the cel was stuck to its bag. On prying the two apart, the paint texture was no longer hard but soft and sticky. The plastic had visibly warped and distorted, and there was a visible “sweat” on the surface of the cel. When it was wiped off, the surface underneath turned from transparent to a translucent gray.

In addition, cels stored on nearby pages showed some minor warpage and also had the chemical smell, though to a lesser degree. The collector noted that these were not necessarily the ones stored adjacent to the deteriorating cel, though they were ones from the same series and studio, suggesting that the stock used at this time was, perhaps, cheaper and more prone to deterioration. After removing all of these, the chemical smell persisted until the collector also removed the black paper from the pages where the affected cels had been stored. It seems that this paper absorbs and traps the chemical smell, continuing to give it off even when the cel is no longer present.

Collector 2 purchased the affected cel in 2010 and did not notice any signs of trouble at this time. It was a four-layer set-up, all of them stuck together, along with the original production background. About two years later, this collector was doing a routine visual inspection of cel books and noticed an incredibly foul, vinegary odor. The scent was traced to its source, and the set-up was pulled for inspection. There was a clear liquid visible between the third and fourth layers of the stack of cels, and the bottom cel was not only soft to the touch but bent like damp paper. The collector separated the cels and tried to wipe off the liquid with some ordinary tap water. As a result, the soft part of the cel visibly warped and turned white or cloudy. The background, which had been stored next to the stack of cels, but in its own cel bag, also had picked up the same vinegar smell. The collector discarded the cel bags and carefully washed all the instruments that had come in contact with the affected cel to prevent contamination of other items in the collection.

Both collectors had used normal precautions in storing these cels and could point to no dramatic changes that could have precipitated the reactions. Since the beginning of the acute phase of this process, they have monitored the cels closely and find that they continue to smell of vinegar but have deteriorated less rapidly now that they are being stored in a setting where they can air out continually.

I’m collector 3, though my story is not as dramatic. I purchased two cels from a pre-90s series last year, and when I received them and removed them from their cel bags, I immediately noticed a heavy vinegary odor. The first was a four-layer cel set, stuck together, and I could see that the trouble lay at the place where the bottom two layers were most tightly stuck. The second, a less severe case, was a three-layer set, and again the problem came where the middle layer was stuck to the bottom. With a little paint damage, however, I was able to separate the layers, and I immediately quarantined both sets, sandwiching all the cels with MicroChamber paper and placing them in wide-open bags so they could vent the fumes. So far I have not yet seen any really catastrophic damage, but I’ve had to replace the MicroChamber paper for both, as the fumes have built up enough to surpass its neutralizing capabilities.

The most distinctive characteristic of my sets, other than the distinctive vinegar odor, is the prominent warping of the cel layers above the trouble spot, and a distinctive “washboard” rippling of the top of the cel around the central registration hole. So far I have not yet spotted the fluid discharge or clouding of the plastic noted by the other two. However, the cels have not and will not be housed with my others. And as a precaution I added a sheet of MicroChamber paper to all the other cels that I own from this series, even though I have not yet detected any odor as prominent as that given off by these two sets.

I’ve looked over a number of sites dealing with vinegar syndrome and the problems of various kinds of cellulose-based plastics, and also some sites dealing with the strategies being used by libraries to postpone or, if possible, avert this kind of deterioration. Here are a couple of preliminary conclusions.

1. All sources agree that cellulose acetate is intrinsically unstable and especially vulnerable to deterioration. An especially interesting web article for collectors of knives (whose handles are often made of celluloid materials) called the material “a time bomb which no doubt can and could destroy some special [items] that you have in your collection.” So vinegar syndrome and other signs of trouble will probably become part of most serious collectors’ experience as time goes on.

2. There are many unknown factors in this process, especially what environmental factors trigger the start of the acute process. But there is agreement that high heat, especially in humid conditions, will predispose celluloid objects to self-destruct. So a cel that has been stored in a non-air-conditioned storage facility in Japan may be a ticking time bomb from the moment you obtain it. However, a second predisposing factor is storing them in ways that allow fumes to build up inside the containers, allowing the reaction to fester and spread. (The reaction was first described in India, when movies on alleged “safety film” were found to be decomposing inside air-tight cans stored in outdoors sheds.) So housing cels inside plastic boxes or in sealed cel bags may also encourage their slide toward deterioration.

3. That said, the Disney Animation Research Library, which maintains a “state-of-the-art storage facility,” has observed that many of its vintage holdings now exhibit signs of celluloid deterioration, including yellowing, warping, and cracking of cel paint. So we probably should reconcile ourselves to the limited lifespan of any cel, however well maintained.

4. That said, there should be more attention given what Karen Hong Saracino calls “prudent general care” for cels. This includes

1. Handling cels infrequently and cleaning them in the least intrusive way possible

2. The use of MicroChamber paper or mats in the storage space

3. Storage in a low light or no-light environment, with relative humidity level of about 50 percent (lower can cause brittleness), and a temperature range of between 68-72 degrees F.

4. Physical examination of all cels should every three months to check for signs of trouble, and thorough airing-out of every one of them once a year.
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Re: Vinegar Syndrome: A warning for cel collectors

Post by BuraddoRun »

I'm sure you've posted it before Sensei, but where do you purchase MicroChamber paper from? And what size do you use? You just slip it in front of the cels, right (non-paint side)?
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Re: Vinegar Syndrome: A warning for cel collectors

Post by Sui Kune »

Thank you, thank you, thank you for this, Sensei. :bow

I've worried about Vinegar Syndrome ever since I first learned of it, and I really want to do everything possible to slow it down. One of my Vinegar Syndrome cels also happens to me one of the rarest and most valuable (and expensive) in my collection, so it's even more personal. (This one, for the curious.) Should I quarantine the background from the cel? (It was once stuck to the cel but was ripped from the cel by a previous owner, and now only sits behind the bagged cel.) I had been doing yearly checks, but I'll check every few months now. I'll also go ahead and empty my second Itoya into my first and put the two Vinegar Syndrome cels in it. May I ask how far from the other portfolios I should keep the Vinegar one? I store them much like you mentioned you do, upright on a bookshelf in open cel bags (mine conveniently come with no flap at all, so no bag cutting necessary!) with an unused dye-free cotton t-shirt draped over the top of the portfolio to keep light out.

I'm also relieved to see my environment is pretty much spot-on for cel storage. (45-50% humidity on average, room temperature 60-70 degrees during the winter, though unfortunately during the summer when rare heat waves happen, it can get as high as 80, but the humidity stays nice and low.) I need to remember to still be vigilant, though! I still need to bag all my paper sketches and backgrounds, and perhaps get them a separate Itoya as well.

ETA (8:37pm PST): Just rebagged everything and discovered a few more with mild to moderate vinegar smell. The two I mentioned earlier are still the most pungent, so I seemed to have least caught these guys early on. All the Vinegar cels are now isolated in their own portfolio, Microchambered, and their (sadly smelly as well) sketches separated to the opposite end of the portfolio and Microchambered as well. (And the same with their backgrounds.) There doesn't appear to be any worse deterioration in Saturn, but the other kinda-bad one I noticed some tiny brownish spots on the acetate. I believe they were there when I received the cel two years back (you can just barely see the brown to Hotaru's lower right), but I'm wondering if it could be a bad sign for this cel.

Coincidentally, I noticed the smell more often in cels with more of the flesh tone color paint, which I also noticed is more likely to have line fading in lines completely surrounded by that color. Of course, my collection isn't anywhere near big enough to really have a big enough sample to conclude something from, but just something interesting I noticed.
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Re: Vinegar Syndrome: A warning for cel collectors

Post by sensei »

BuraddoRun wrote:where do you purchase MicroChamber paper from? And what size do you use? You just slip it in front of the cels, right (non-paint side)?
I get mine at Bags Unlimited, the 8 1/2 by 11 size, which I often cut in half for less demanding jobs. But there are other sizes, so shop around. It's pricy in the small sizes, so I tend to get it in the 250 sheet quantities. Ms. Saracino talks about making a mat out of microchamber matting board, which might be a good idea, but would be terribly time-consuming for a collection my size. So I put the sheet in front of the cel. However, I've never seen a cel stick to microchamber paper, even with the ones that I've sandwiched in such paper.
Sui Kune wrote:Should I quarantine the background from the cel? May I ask how far from the other portfolios I should keep the Vinegar one?
I would separate the bg from the affected cel. It seems that the acetic acid fumes are attracted to paper (logical, as paper is mostly cellulose, so the acid is trying to turn the bg into cel stock, even as the cel is returning to its sawdust origins). So if the fumes are likely to be trapped by the bg, that might not damage it, but it might make it capable of spreading the plague to other cels (if I'm reading the "worst case" logic of the websites).

How far? I don't know if there is any recommendation. The Disney site simply says that an international team is studying the phenomenon to try to understand it better and come up with some standards. But I'd think that a different shelf or different part of the room would be sufficient. My quarantined cels are on a bookcase about ten feet from the cel books.

I'd say the logic of what I've read so far indicates that one thing that collectors might take more care in doing is not pack cel books too closely together. The books should rest on the shelf slightly open, so that if a cel is emitting fumes, they will rise up and out into the room, rather than being trapped in the cel book. I can see that I need to do more to implement this in my own collection. So take my last comments as conclusions I'm reaching as I reflect on what I'm learning, rather than a smug description of what I'm actually doing in the here and now.
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Vinegar Syndrome: A warning for cel collectors

Post by KuroiTsubasa4 »

Is this vinegar smell pretty easy to detect? Because most of my cels have some sort of slight smell if I take a whiff. But it's probably just the typical paint smell. Nothing has a strong enough odor to smell it from more than a few inches away.
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Re: Vinegar Syndrome: A warning for cel collectors

Post by sensei »

Yes, it hits you in the face when you open the bag, and both my sources said it was prominent in the room even before you open the bag. I make a habit of sniffing cels now, and find there are a variety of scents. A "healthy cel" smell is like a fresh photocopy hot from the machine (same plasticizer used to fuse trace lines to the back of the cel). A source described an older "cel paint" smell as "cheesy." And some poor cels come with an unmistakeable scent of Japanese mildew, which you know at once after the first time you've gotten some slightly moldy sketches or bg. None of these are trouble, but anything that slightly says "vinegar" to me means that a MicroChamber sheet (sometimes two) goes in the bag right away.

I think (but could be wrong) that the reaction causes a disproportionate amount of odor to the area affected. So a little sniff of vinegar could mean a dust-speck of affected plastic. But as it's an irreversable reaction that can become acute with little advance warning, I'm now thinking that over-reaction is better than wait-and-see.
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Re: Vinegar Syndrome: A warning for cel collectors

Post by zerospace »

Wow... I guess I'm lucky enough to have never run across this, despite having some older shows in my/the hubby's collection (Macross, Transformers, etc). We've been going through our cels quite regularly lately, too, thanks to our efforts to shrink the size of our collection.

I've definitely noticed the Japanese mildew smell on cels (ugh... more often than I'd like, but I have been smacked in the face by it enough times on opening packages containing YJ wins), but never a strong smell of vinegar (a smell I'm quite familiar with thanks to using hot vinegar for pickling metals after soldering/brazing). Nearly everything we get ends up with an airing out period, because I frequently pile unscanned cels and sketches near my scanner for a month or longer sometimes until I have time for a scanning session. I hate this habit, though, as I use daylight type lamps on my nearby workbench and always worry about the effects that light might have on the relatively unprotected cels (I do shield the cels from the light, but it still bothers me that it's so close).

Our cels are stored in what amounts to a nearly zero-light environment (cel books & storage boxes kept in a closet that is closed about 95% of the time). Our humidity levels, though, are very low here. In the summer, it is not uncommon to have humidity below 30%, even in our house (outside it will sometimes be as low as 10%). I've been mulling the idea of a humidifier all-around for our house, as heat in the winter makes things dry along with the summer desert-like environment keeping things dry in the summertime too, and this makes me think that such a thing would also be good for our cel collection :).

Thanks for the info, sensei -- this was really educational. :bow
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Re: Vinegar Syndrome: A warning for cel collectors

Post by Matt »

Hi everyone,

I just wanted to point out that micro-chamber paper was created for preservation of paper and photos. I was in contact with a supervisor at bags unlimited a number of months ago (like 9-10) and asked if I could use the micro-chamber paper for animation cels. He contacted the company and asked them the very same question. The representative he spoke with said that there are NOT any studies at least through them, the manufacturer of the brand micro-chamber paper, on the use of their product and animation cels. The representative went on to say it would be an interesting experiment to see if there were any effects of the product and the cels, however, the bags unlimited guy couldn't express to me enough that the representative said that micro-chamber paper company itself would not be held liable for any damages to the cel.

I don't want to burst any bubbles or cause any problems but I saw how many people are using micro-chamber paper for cels and I couldn't let myself sit by with this info while hundreds of cels could be danger. Again, this is just information that I have received that I wanted to share and let everyone make their own choice. Personally, I love micro-chamber paper. I use it on all my comic book art and sketches. It has taken away old age smells and even yellowing from some of my old 1960's storyboards. But I will not use it on my cels.

As far as the vinegar goes, I guess I have been lucky not too have dealt with that, I do make it a point, it is actually marked on my calender, to change my cel bags once every year usually in November when it's not too hot out. I let them breathe for a while and then bag them back up and I haven't had any problems with line fading or stinky cel.

Anyways, here's to keeping our collection safe and sound :cheers

Matt
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Re: Vinegar Syndrome: A warning for cel collectors

Post by sensei »

Ms. Caradino's recommendation is based on the practice of the Animation Research Library of the Walt Disney Company, which in 1999 initiated the use of MicroChamber paper in consultation with William K. Hollinger, President of Conservation Resources International and the inventor of the MicroChamber concept. The paper is permeated with zeolite, which actively traps fumes that would otherwise spread and accelerate the deterioration of the cel, and neutralizes them. The Walt Disney Family Foundation, a smaller but higher-quality collection, also uses MicroChamber technology.

The manufacturing company, Conservation Resources International, did test the properties of its product on a wide variety of materials, including an animation cel. Its detailed account of its tests, during which the cel was exposed to high concentrations of atmospheric pollutants, was that the section protected by MicroChamber paper was undamaged, while a portion of the cel left unprotected as a control did show visible damage.

I would be cautious about placing the paper against the painted side of the cel, as I know of no tests that would show whether the paint would stick to the paper, causing a new problem. However, all MicroChamber products are made from lignin-free and sulfur-free paper, and, according to the manufacturer, "they pass or exceed the requirements of all archival standards, including the Photographic Activity Test (PAT)."

Archives other than Disney do use other methods, and Saracino's thesis describes these. Collectors can and should make their own judgments, but before doing so I'd recommend that they read her well-documented thesis and carefully review some of the tests that Conservation Resources International ran on their material before recommending it to Disney.
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Re: Vinegar Syndrome: A warning for cel collectors

Post by zerospace »

Sensei, I'm hoping perhaps you have some information regarding a couple of questions:

1) Does humidity or temperature of storage seem to have any relation to vinegar syndrome?

2) Does it seem to affect any particular studios' artwork more than others?
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Re: Vinegar Syndrome: A warning for cel collectors

Post by sensei »

Good questions, both. But even Saracino cautions that the exact course of cellulose acetate is so unpredictable that no one at present has a 100% dependable program for averting serious deterioration. Lots of Disney cels (made of cellulose nitrate, which is even more prone to deterioration) are in great shape today, while at least one housed in Disney's state-of-the-art facility is visibly warped and the paint cracked. That's one of the creepy things about the condition: it can happen very quickly, or not happen at all for decades.

Probably that's the motivation behind the curator who actually refused to talk to Saracino at all. This person feared that sharing a course of action that made sense and appeared to work for that facility could lead to litigation if it was followed by someone with an 8-million-yen Castle of Cagliostro cel who woke up one morning to find it messily self-destructing.

Disney and the Getty Conservation Institute are carrying out the lab science needed to shed some chemical light on the issues involved. This is why I'm more prone to follow (to the extent that I can, financially) Disney's program of conservation rather than trust another archive's methodology. But collectors need to do research on their own, which is easy to do as there are "vinegar syndrome" discussions available for a wide range of collectables, notably historic films, which, being stored in tight rolls of cellulose acetate in airtight canisters, are even more prone to the condition. I have not seen any of the cels that I've maintained over 12+ years suddenly develop the condition, but I'm concerned and don't wish to take the risk by simply hoping for the best.

That said, the consensus is that high temperatures, accompanied with high humidity, have been commonly linked to the start of the destructive process. How high? That's unclear. Maybe the lab research being done by Getty will provide some clearer perimeters. In any case, the mainstream recommendation is to try to maintain a storage temperature around 68-72 degrees F. and a humidity level of about 50% -- i.e, not super moist but not super dry either. I've also read that if storage conditions can be reduced to about 55 degrees, the expected lifespan of films, negatives, and other acetate-based collectables (such as cels) also increases.

I should reemphasize that none of the cases reported to me were due to neglect on the part of the present owner, and so I assume that if there was any inappropriate treatment or storage that triggered the start of the condition, that took place before the cels changed hands.

As for studios prone to the problem: that's even less clear. One difficulty is that if a group of cels show similar tendencies (as with my batch) that might signal a number of things. It could indicate an inferior batch of acetate produced by the same manufacturer for several studios, or a cost-cutting measure by a studio needing to save money, or (my personal guess) inappropriate storage of the cels between the time they were discarded by the studio and before they were sold at auction. I can well imagine some of these cels in a closed plastic container in a steamy hot storage facility, with one poor unfortunate melting and spewing fumes in the very bottom. So far I have not seen any correlations among the reported cases.

But if more people know about the condition, then we'll see more reports, and perhaps we can get a sense of what types of cels are most commonly affected, and under what circumstances.
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Re: Vinegar Syndrome: A warning for cel collectors

Post by zerospace »

Very interesting, indeed, sensei. Thanks :).
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Re: Vinegar Syndrome: A warning for cel collectors

Post by Matt »

Hi everyone,

Again, I just wanted to share the information that I was told. I thought I was Just trying to help the community

Thanks,

Matt
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Vinegar Syndrome: A warning for cel collectors

Post by KuroiTsubasa4 »

Ugh. My cels at home are safe but they have to endure very cold temps
during Kyoto winter and hot temps during Kyoto summers before I bring them to NY each July. Luckily I leave my aircon on often so they don't get too overheated. I wonder how fast the process can be activated... Though if people are receiving cels with mildew smell is it pretty safe to assume that the average cel dealer on Yaj doesn't follow these rules? Ever since the nuclear plant issue offices have really been working hard to save power and the aircons have been the first to go :(
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Re: Vinegar Syndrome: A warning for cel collectors

Post by BuraddoRun »

Matt wrote:Hi everyone,

Again, I just wanted to share the information that I was told. I thought I was Just trying to help the community

Thanks,

Matt
We appreciate it, Matt. Don't feel bad. I'm sure the seller of the paper was just trying to let you know that he simply didn't know what would happen when using it on cels. Liability issues, you know. That's why Sensei suggested that we all do our own research, and responded with information that's he's researched himself. Remember, all of this is still being researched as there are no conclusives available right now. The purpose of this topic is to educate we collectors (Thank you Sensei very much for starting this topic), and share information and experiences that we have.
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