Concerns about nitrate-based vintage negatives

[Darner]

With all the vintage photography being sold these days, I've come across some negatives that are on nitrate stock including a few George Burke negatives from the early 1930's. Cellulose nitrate was introduced as a flexible transparent film base back in the 1890's. The problem with nitrate is that it's unstable and breaks down, becoming sticky, gooey, then ultimately turns into dust all the while releasing nitric acid. Worst still it is extremely flammable and if deteriorated can spontaneously combust. There were a number of incidents and deaths in movie theatres in the 1920's when projected films burst into flames, and in the 1970's both the National Archives and the George Eastman House lost films they were storing when they self-ignited. Because of the hazards of nitrate, "Safety" acetate film was introduced it the 1930's but did not replace nitrate entirely. I'm not sure when nitrate was phased out as a still film but nitrate movie stock continued to be made until the early 1950's.

I'm not an expert on this but it seems to me if you collect vintage negatives, you have to be aware that nitrate film can be hazardous and if you decide to keep them, you have to be able to store them as safely as possible. There's quite a bit of information about nitrate film on the web. Any negative marked "Eastman-Nitrate-Kodak" is nitrate. Unfortunately some marked with the words "Safety" can apparently also be nitrate. Here's a webpage that can help identify the film stock: http://crossover.ellison.net/NegsID.htm Wouldn't want anyone's collection (or house) to go up in flames.

[thecatspajamas]

Has anyone ever heard of photography nitrate film spontaneously combusting like this? Every incident that I have heard of was related to movie film doing this, and my understanding was that the spontaneous combustion necessarily involved having a high concentration of degrading film confined in a small, relatively airtight space so that the fumes given off by the degrading film remained in high concentration rather than dissipating into the surrounding air, and that high concentration of fumes actually accelerated the degradation of the film. The tightly wound reels of movie film stored in metal canisters provided just such a situation, but I don't recall ever hearing of photographic film spontaneously combusting. That's not to say that one couldn't orchestrate conditions that could lead to it, or that it has absolutely never happened with photographic film (I really would like to hear of any incidents anyone may be aware of), or even that I am any kind of expert on the chemistry involved, but I don't think of the nitrate negatives that I have on hand as ticking time bombs.

In addition to any incident reports, I'd also be interested in seeing what degrading nitrate film actually looks like so that I know what to be on the lookout for.

[Darner]

I've read that ambering or yellowing is the first indication that the nitrate base is breaking down. There might also show some mirroring in the silver emulsion.

I agree that the way sheet film is usually stored does make it safer (smaller quantities, individual envelopes, not in air tight containers, room temperature) but it's the same material and still has to be carefully handled. For conservation sake I'd put them in cold storage to prevent deterioration and I'd keep them separate from other kinds of negatives in case they do give off any gases that can damage something else.

Probably the worst case scenario is someone stores a bunch of nitrate negatives closed up in a box and they decompose over time in a hot attic.

[thecatspajamas]

Ed, I hope it didn't sound like I was trying to contradict you. I am genuinely interested in hearing of any accounts of these combusting and/or details of how they break down. As you say, I think their typical method of storage staves off the former, but even so, the latter would still be a concern.

Burke/Brace kept theirs in envelopes in file cabinets, which I would guess is the most common storage method for photographers and newspaper archives alike over the years. Most that I have seen of Burke's seem to have held up well as far as the stability of the film itself (though judging by fingerprints, scratches and other flaws, perhaps not handled with as much care as we would have liked). I suppose the basement of a Chicago residence is pretty close to "cold storage" for much of the year I wonder how they would compare though to a photographer based out of, say, Florida?

Lots of great info in the page you linked to, and the pages and documents that page links to, that I'm just starting to digest. I REALLY like the page with the graphics for identifying film types by notch codes and wording on the film, and only wish that they had included years of production for each film type in the chart as well, though I suppose the actual dates were outside the scope of what they were looking at. I may just have to add that to my ever-growing list of research projects to fill in those dates though unless I discover the info already detailed elsewhere. (That should be read as a subtle plea for anyone to point me to where that info may be detailed and save me from my own ambitions. Somehow keeping nitrate film on the back burner sounds dangerous, even if I am just talking about the dating of it).

[drcy]

Celluloid, a vintage plastic used to make film, billiard balls, toys, fountain pens, pins, mirror and brush handles, etc. is flammable. That's one reason why they discontinued making it. However, I don't think that means it's a major hazard to humans life and limb. Your celluloid pins aren't going to explode in your closet, and, of course, a stack of Baseball Magazines is also flamable. But they should be kept under good conditions as celluloid often can deteriorate/age with time. Degraded cellulid pins and such get cracks, alegator skin and discolorization (toning).

Old movie films were famous for melting and catching on fire in the projectors, but that was under the heat of the projectors while being shown. They wouldn't suddenly combust on their own sitting in a drawer.

Celluloid was first use to make fake ivory billiard balls and was commonly used to make other fake ivory items. Allen & Ginter pins are celluloid. And many of these still exist.

Anne Frank wrote her diaries with celluloid pens, and her favorite one burnt up in a small, minor fire in her family's hideout. She wrote about it in her diary. She knew the pen was celluloid and was well aware celluloid pens were flammable. Apparently, it was common knowledge back then. The pen and a blank diary book were given to her for her 13th birthday and that's when she started writing her famous diary.

The can of turpentine in your closet is more dangerous than old film.

[Runscott]

Reminded me of this scene from 'Cinema Paradiso' where the film catches fire:

Cinema Paradiso - Fire Scene

[Chris Counts]

A few years back, I purchased about a half dozen baseball negatives from the late 1930s. A couple months later, they morphed into a weird science experiment. They crackled and bubbled and curled. They were completely ruined, so I disposed of them for fear they might ignite ...

[steve B]

Originally Posted by drcy

Celluloid, a vintage plastic used to make film, billiard balls, toys, fountain pens, pins, mirror and brush handles, etc. is flammable. That's one reason why they discontinued making it. However, I don't think that means it's a major hazard to humans life and limb. Your celluloid pins aren't going to explode in your closet, and, of course, a stack of Baseball Magazines is also flamable. But they should be kept under good conditions as celluloid often can deteriorate/age with time. Degraded cellulid pins and such get cracks, alegator skin and discolorization (toning).

Old movie films were famous for melting and catching on fire in the projectors, but that was under the heat of the projectors while being shown. They wouldn't suddenly combust on their own sitting in a drawer.

Celluloid was first use to make fake ivory billiard balls and was commonly used to make other fake ivory items. Allen & Ginter pins are celluloid. And many of these still exist.

Anne Frank wrote her diaries with celluloid pens, and her favorite one burnt up in a small, minor fire in her family's hideout. She wrote about it in her diary. She knew the pen was celluloid and was well aware celluloid pens were flammable. Apparently, it was common knowledge back then. The pen and a blank diary book were given to her for her 13th birthday and that's when she started writing her famous diary.

The can of turpentine in your closet is more dangerous than old film.

Celluloid covers a number of plastics. The ones used for movie film and still negatives are different from the less flexible versions.
I own films on at least four film stocks, probably five. That includes nitrate movie film. I've also burned both nitrate two types of safety film.

Cellulose nitrate - Nitrate film, in movie film it was phased out in different years for different formats. 16mm introduced in 1923 was never on cellulose nitrate, 35mm was often on nitrate until 1948 when cellulose triacetate was introduced. Production stopped at Kodak in 1950, and it was discontinued in 1952.
It burns very aggressively, and is self oxidizing so it's hard to extinguish.
The byproduct released is nitric acid, and in non-vented containers will eventually self destruct. It can spontaneously combust, but I haven't heard of that happening with still film, although it was apparently a major problem with stored x rays.

Cellulose diacetate - from 1909, an early safety film. I had what I think was a 1920's film that was not marked as nitrate or safety. It may have been this. Odd degrading, brittle but hardly any shrinking. It burned, but slowly, sort of like a candle. (That was my test for whether it was nitrate, took a torn frame outside and lit it in a metal tray. Nitrate goes up very quickly, this stuff hardly at all.

Cellulose acetate propionate and cellulose aceteate butyrate - 1930's safety film, used for all 16mm, 8mm, and some 35mm before 1948. As it degrades one form gets a bit of a barfy smell. (can't think of a better way to describe it. ) The other just shrinks and gets brittle.

Celulose triacetate - the common modern filmstock. Introduced in 1948, and it came in nearly formats eventually. Degrades by releasing Acetic acid (vinegar) but it's very stable and will take a lot of abuse before it degrades. Badly degraded film smells like vinegar and eventually shrinks curls and becomes brittle. It can be burned, but burns poorly.

Polyester - Mylar/Estar a few other brand names. Essentially inert, it can burn, but it's not easy to light. It melts at around 490F, so if your mylar is melted or burning you've already had a problem for a while.

Of those, only Cellulose Nitrate is any hazard.
By some tests, it's not a particular hazard outside of severe conditions
http://motion.kodak.com/motion/Suppo...ge_nitrate.htm

The relevant bit - a badly decomposed 1000ft reel in a sealed container took 17 days at 106F to retain the heat of decomposition.

In small pieces of good condition fillm it's manageable, and less likely to ignite.
http://www.youtube.com/watch?v=7mZDt8vYMBw

But once it does, it's Trouble.
http://www.youtube.com/watch?v=AL9izOFrqbw

http://www.youtube.com/watch?v=g00nYOueqSI

Deteriorated and tightly packed.
http://www.youtube.com/watch?v=SccNL6mfX2Q

So still film is probably not much risk if it's properly stored. Archival envelopes, not densely packed, and kept cool and dry.

A few hundred stacked in a box in the attic? Not something I'd do.
I keep my nitrate films in the refrigerator. Eventually I'll get around to getting them to someplace that can preserve them and store them properly.

Steve B

[Darner]

Thanks for that information, Steve.

The point is that you have to know what you have and then take care of them. All these early film stocks break down so if they're to last, they have to be stored properly but the flammability of nitrate and the noxious byproducts of its decomposition requires more attention.

I only have a couple of negatives from the '30s and they're not nitrate but when I bought them I had no idea what kind of stock they were. You usually can't tell from an auction listing and as a newbie, I didn't know to look. I can see nitrate being problematic for sellers. How would you even ship them if you can't legally put them in the mail?