Safely using old-stock Nitrate / Nitrocellulose film?
Does anyone have any advice/suggestions on how to "safely" use old-stock Nitrate (Nitrocellulose) based films?
I'm not talking about the typical stash of old negatives from the grandparents, or cine film movies in the archives... but rather, exposing/developing/archiving NOS rolls of unexposed film.
The reason I ask: I have recently come across some WWII aerial film, with an expiration date of Feb 1944. It is generically boxed with the green labels, unopened, and with several emulsion and type codes but without any manufacturer listed. I know that safer film bases were available at least as far back as the early 1930s, but until I can do a flammability clip test, I'm going to go ahead and assume that this is the "bad stuff" and plan accordingly.
As a starting list, these are the tidbits I have gathered from various sources:
- The film may have already decomposed into flammable powder or goo, so it might not even be usable.
- A fire will be fast and difficult to suppress, and water doesn't necessarily help (reactions produce oxygen, so it can keep burning anyway, and the water increases the amount of smoke)
- The gasses produced by a fire are highly toxic
- Decomposing film produces nitrogen oxides (gasses), which are toxic and corrosive to metals when in the presence of water
- Dry film can ignite when subject to heat or shock
- Gloves and goggles should be worn when examining film
- Film should be discarded when it shows signs of decomposition (soft or sticky surface, etc)
There are several "official" reports on how to deal with this type of film, such as "the Standard for Storage and Handling of Cellulose Nitrate Motion Picture Film" published by the National Fire Protection Association (NFPA), but based on the summaries I have read, the safety & storage requirements seem to drop off significantly when the amount of film being stored is less than 25 lbs. I have about 4.5 lbs (including container, spool, & box weights), but that doesn't mean that I'm not taking it seriously. I have also seen this quote many times in different places: "While decomposing motion picture film has been known to self-combust, still-camera negatives has not." I suspect this difference is due to quantity or perhaps even just the statistical likelihood based on the quantities...
So, all of that being said, here are my preliminary thoughts:
- Store the film (unexposed AND exposed/developed) outside, in an old BBQ grill which could safely handle a fire, a reasonable distance away from the house
- Scan and print the negatives instead of using an optical enlarger (and the associated heat-producing light source)
- Divide the film into separate metal containers so that a single fire will not (necessarily) involve the whole batch going up
There are also things I am unsure about... such as whether the metal storage containers should be sealed or vented, whether static electricity can ignite the film, or how much of an impact (and with how much film) it takes to self-ignite dry film.
Any thoughts would be appreciated. This is an area where the doesn't seem to be a lot of information (or even awareness!), outside of the motion picture or museum archival houses...