Nitrite films

Hi all,

Hope everyone had a great holiday! I finally have some free time

and have been organizing and filing my fathers many negatives (35mm

through 4x5) from the 20's through the 50's which I've been wanting

to do for a long time. My question is this...is there a (chemical

etc.) test for determining which emulsions are nitrite based or not?

Some of these films have names like Agfa Supreme Pan, Ansco Superpan

Press and Agfa Superpan Press, but most are unmarked. The ones

marked Safty film I know are non-explosive. It is interesting as

well as emotionally cathartic to see my fathers life from so long

ago in great detail with the actual negs. It brings to mind that all

of our lifes work after we have passed will naturally enter into the

realm of catagorized historical documentation.If not somewhere else.

Peace.

Well, one way, cut off a small snippet of film, HOLD IT IN A TWEEZERS, light it and if it goes off with a flash of flame, a cloud of smoke and hearty HI HO SILVER-AWAY!, you got nitrate.

 

However, I would really wonder if you have any. 80+ year old nitrate don't usually look too good. In fact, nitrate films from the late 1930's have deteriorated past retrieval in some cases.

Kodak publication H-182, "Safe Handling, Storage, and Destruction of Nitrate-Based Motion Picture Films", http://www.kodak.com/US/en/motion/hse/safeHandle.jhtml, has much excellent information. For use by someone with a small quantity of still photography negatives, the advice needs a little interpretation, e.g., the document sets a storage quantity boundary at 750 pounds.

 

Besides the methods for identifying nitrate based film, another critical section is on classifying the film according to five stages of deterioration.

 

Recent documents on nitrate film seem to have a less panicky approach compared to earlier ones. While nitrate film isn't safe (neither are many other materials in the typical American house), one can overreact: it is not explosive. It is highly flammable. In large quantities, such as movie reels, stored in tighly sealed containers, such as for movie reels, it can spontaneously combust. Small quantities of negatives that are ventilated can be regarded as other flammable materials.

Or to put it simply, you know that flash powder they used to use for a flash way back when? It was really just ground up film!

I worked with a large collection of Nitrate negatives years ago when I was the photo technician at the Provincial Archives here in Nova Scotia. Nitrate is fairly easy to detect, once you are familiar with it. Undeteriorated nitrate will likely still have a distince smell (sharply acidic) and deteriorated Nitrate is pretty unmistakable, ranging from a buckled film with an oily, almost tarnished surface. But I agree, the easiest way is to shave a sliver off the edge of a film, and light it - Nitrate burns furiously.

 

In regards to the film, once you identify it, I would make fibre prints of the most valiable ones, at a minimum. What I did at the lab for the collection we had (5x7 pyro developed negs) was make contact film positives for long-term archiving - new contact negatives could be made from the film positives as required, and the film was expected to have a longer (and more accuate) tonal scale then a print.

 

Hope this helps - have fun with your collection!

 

e.

Here is the "burn" test as I know it. I am not sure where I read about this method and I remember that it is not considered completely reliable. It is easy. Both nitrate and the current acetate film bases will burn under some conditions, so mere flammability isn't a way to distinguish between the two. Hold a small sample (e.g., 1 x 2 cm, oriented long-dimension veritical) with pliers. Hold a match to the top, then remove the match. Nitrate film will ignite and the flame will propagate downwards. The acetate film will burn while the match is in contact, but the flame will go out when the match is removed. If the match is applied to the bottom, both types will burn in a similar manner! I have tried this with the current acetate film base and with film I suspected of being nitrate.

Thanks all for the very usefull information regarding nitrate films. Indeed, and unfortunatly, some of the nicest negs seem to be nitrate, upon observation of the oily surface w/buckling. These negs have been stored under a lot of conditions including hot attics etc. with no problems for many, many years. But they were in boxes loosely packed. I have filed them in archival clear negative pages but I am now thinking that this might not be good as there is little to no air circulation with this method so was wondering the thoughts of the forum members if box storage would be best? I really dont want to destroy these negs after the contact prints are made so if I can store them safely I will. Any help is much appreaciated. Thanks a bunch!

At the archives where I work on contract, we have a large number of nitrate negs. They are in a wide range of conditions and ages.

 

In the past these have all had "working" copy negs made from them. Many have also been scanned.

 

The originals are stored in individual archival paper sleeves, then vacuum packed in groups in foil packets and kept in a freezer. This prolongs their life by drastically slowing down deterioration. It also reduces the risk of sponatious combusution. (the freezer also happens to be explosion proof - from the inside that is...!).

 

If you really want to preserve them, copy them in some way - copy negs or scans, then you could fairly easily store them this way at home. You can get the paper sleeves and foil packets from various archival supply houses that service museums and archives (generally cheaper than the likes of Light Impressions, if they are still in businness) and you can use one of those home vacuum sealing things you use for freezing foods. (I'm not sure off hand what temperature ours are frozen at)

 

It may be a bit of overkill, but they will continue to deteriorate without further control. And there is something an increased combustion risk of a bunch storred together (not as much as say reels of tigthly packed fim, as has been mentioned).

sponatious... hmmm