The effects of delaying development of exposed film

[Patrick Troccolo]

How long can I store store exposed B & W film. What are the effects of long term storage before processing. Any suggestions on how to compensate for long term storage?

[Jim Rice]

If reasonable conditions can be assumed, my guess is very little to no degradation. I'm pretty sure that there is no difference between "latent image" storage, and just film storage. Am I wrong?

[Bob Crosley]

I store exposed film in the freezer in a ziploc (with some drier packets). I certainly haven't noticed any 'storage effects' when kept frozen for a month or two. My guess is that you could store exposed film frozen for many years with little harmful effect. My films are txp, hp5+, and fp4+.

[David R Munson]

I have a box of unprocessed film in my room. The deeper you go, the older the film. My guess is that the film at the very bottom is a year or two old. When I develop film I try to do some of the old stuff along with the new stuff. About the only things I've noticed are a little less contrast and a little more base fog. Nothing to worry about too much unless you've left the film in the oven for a few weeks accidentally.

[RichSBV]

A couple of years ago, I was digging through some old camera stuff and came across one of my spare bodies. It had film in it, Tri-X B&W as I remember. I had no idea how old it was, but must have been at least in the 10 year range. For the heck of it, I shot the rest of the roll and developed it in normal processing. The new exposures came out a stop or two under exposed as would be expected. The original exposures came out like they were shot on new film. And from them, I could tell that the film was at least 20 to 25 years old! And there was absolutely no special care taken in the storage on the camera. Sat in a box for all those years...

[Ron Bose]

According to Mike Johnston (in Black and White Photography) to get the best out of the film you should process it within 30 minutes of exposure. During the first hour the latent image will degrade to a certain extent. Then it'll hold steady for six to twenty-four hours. After this it'll deteriorate slowly.

Apparently, the exposed grain clumps migrate within the emulsion. Flat highlights, mealy grain and indistinct tonal areas are the results of not processing soon enough.

He also says that Tri-X is tolerant to such delays more than others. Kodak tmax p3200 and agfa apx400 are not so.

(Shamelessly summarised from Mike's column)

[Ben Calwell]

I once stored some exposed Tri-X sheet film for more than five years in my refrigerator ( I had no home darkroom at the time). When I finally processed them they turned out, to my eye, to look great. I could see no degradation in the image.

[Ralph Barker]

Ron - interesting claims made in Johnston's article. Do you have a citation for the article? I'd love to read more about how he came to those conclusions, and see comparison images that support his claims. (Please note that I'm not criticizing you for passing the information along, but rather questioning Johnston's conclusions.)

[Philippe Gauthier]

What is said above about the degradation in the first few hours is true, but of little practical consequence. All B&W films will keep their latent image in a very good condition for at least a year, and in a fair condition for much longer.

The exception to this apparently Pan-F; according to Ilford, it should ideally be processed the same day, and always within 10 days or so of exposure.

[Ron Bose]

The information included in Mike's article doesn't go into substantiating his statements. I've included most of the comments made in his article.

He did cite one other fact which I left out of my (above) post, which was regarding Tmax P3200. He said that if an exposed roll is left for a year (presumably not refrigerated) without development, the roll is not worth developing and printing.

At face value and his credentials, I accept Mike's comments. Also, from a chemical engineer's perspective (my academic background), I can imagine at the granular level, the structure and form of a grain exposed to light will change. A reaction could then take place between adjacent grains which have experienced differing exposure to light. This 'may' result in 'muddying' ???

I'd be interested in any more scientific reasoning.

I also suspect that some film will be much more sensitive to this phenomenon than others ....

[Paul Metcalf]

When a photon (light) or two make love (what else do you call it?) to a silver halide cyrstal in the film it absorbs the photons' energy and causes an electron on the halide crystal to escape out into the emulsion. If the electron runs into a positive trap, it becomes, well, trapped. If a free silver ion is near the trapped electron it may absorb the electron and be reduced to silver metal. If enough silver atoms are reduced (some think 4 is the minimum) as a "clump," then a latent image is formed. Actual visible image does not form until chemical development. So, the whole love affair takes light (photons). If exposed film is kept in absolute darkness, then I suspect that any degradation in the latent image is due to the general aging of the materials in the emulsion and should be no more than non-exposed materials. The warnings on the high speed film might be hand-wringing about the effects of beta and/or gamma rays from space, but isn't really an issue with normal speed film. The main reason to develop film ASAP is to make sure you aren't making any mistakes in exposure, etc. and/or your camera equipment isn't failing.

[tim atherton]

"He did cite one other fact which I left out of my (above) post, which was regarding Tmax P3200. He said that if an exposed roll is left for a year (presumably not refrigerated) without development, the roll is not worth developing and printing."

As I recall that's pretty much so for unprocessed TMax 3200 too - there isn't much point in storing TMax 3200 for very long in the fridge or out because it fogs so easily from cosmic radiation or whatever it is....

[Mark Sampson]

Perhaps the best reason to process your film soon after exposure is because you want to see your pictures.