Dealing with speed loss in older film -- best way?

[newcan1]

I have a bunch of different stocks of film that are past dated and that have suffered various degrees of speed loss. Up till now, I have just attempted to re-rate them by taking test shots, and then use them at a reduced ISO based on the tests.

But a couple of weeks ago I shot two rolls of Fuji Pro NPS (35mm), not realizing it had lost speed. I developed the first roll and the negatives were a bit thin, like 1 stop under-exposed. Too late to reduce ISO. So for the second roll, I push processed it for a one stop gain. The negatives just came out of the tank; they look normal in density (but a bit grainy under the loup).

This got me to thinking. I do not fully understand the chemistry of speed loss through film age. But will it always be best to reduce ISO, or does increased development time also have a role to play? Or a bit of both? My guess is reduce ISO, because push processing is likely to cause an increase in grain and a compromise in dynamic range and maybe some cross-over. But what if the speed loss is in part caused by say emulsion hardening, so it does not accept developer as easily? Anyone have a take on this?

 

[ic-racer]

All the film curves I have obtained on somewhat foggy old B&W negative film show a loss of speed. My take on it is that the cosmic rays slowly fog what will be highlight and what will be shadow to an equal amount of density increase. However, in terms of percentage, the fog in the shadows can end up at 100% of the shadow density and the added fog density in the highlight might be only 0.01% of the total highlight density.

So, the cosmic rays eat up the toe and you lose speed and latitude.

Now, global statements like "fogged film has less speed and latitude" won't hold, because of what we know about pre-sensitizing film, where the speed and latitude increase.

So, all the film I have tested shows to me that "fogged film from old age has a loss of speed and latitude."

 

[Gerald C Koch]

The best way -- don't use them. Life is too short and there are so many pictures that need to be taken don't waste your time fiddling with bad outdated film.

 

[jcoldslabs]

I disagree with Gerald. Life is too short to worry about perfect exposures and zone system rules. I respect that approach immensely, but I have been shooting exclusively with outdated film--some if it more than 40 years old--for years and having a grand old time. It's the unpredictability that I like. But if stable, predictable results are your cup of tea, then yes, fresh film would be your best choice.

Jonathan


EDIT: The way I see it you need to increase exposure to push the lower values up through the fogged base, so whether you rate expired film at a lower E.I. or just add a stop or two to your exposures, the end result is that shooting at box speed might not be the best idea.

 

[trojancast]

Like they used to say in the Army, smoke 'em if you got 'em

Seriously, no reason to not shoot outdated film and don't sweat the degradation. Process normally and play with them when you print. You may end up with something very creative.

 

[Gerald C Koch]

But if stable, predictable results are your cup of tea, then yes, fresh film would be your best choice.

I personally don't like darkroom work so I strive to keep my negatives as consistant as possible.

 

[jcoldslabs]

Gerald,

That makes sense. I really like processing film and so am happy to play around with temp, dilutions, agitation, etc. Old film just gives me more wiggle room and chances to experiment. But I'm OK if the results are spotty. To each his own!

Jonathan

 

[newcan1]

I understand where Gerald is coming from -- but if you acquire a large quantity of an outdated film, it doesn't take too much up-front experimentation to establish its speed, properties etc and then you can be consistent with the rest of it. For example, I spent a few hours establishing the new ISO of a 1,000 ft roll of Kodak ECN-2 motion picture film, that I use for stills, and when I did, I knew how to handle the remaining 170 rolls (36 exp) or so! Some of my outdated film is great when tested for speed loss, some is not so great, but I certainly would not give up altogether.

I scanned some of my push processed Fuji NPS film today, and while the negatives are denser than the regularly processed ones, they are still very grainy and this shows in the scans. I have not done optical prints yet -- my sense is that this is a film that was not designed with scanning in mind. But the grain suggests to me that increasing exposure would be more effective than push developing. I'll expose a roll at 64 or 80 ASA this weekend and see what happens.

 

[hrst]

The only real way is to overexpose. The lost speed is lost speed, and increased fog is increased fog. If you push process, you increase the fog even more. If the fog is a problem, you can PULL process or use an antifoggant, but then you will be decreasing the speed even more.

So, I think for overaged film shot at the original ISO, the normal development is near the best you can get.

If you can overexpose it (which you really should always do with old film), then again, normal development may again be near the best, but now there is a possibility to fiddle with antifoggants to get snappier shadows with less fog.

Slide films typically have a severe fog problem when old, ruining the blacks. In that case, overexposure and PULL processing helps a lot. Antifoggant would probably help even more, but pull processing is easier to get. But with negs, you can just print through the fog.

With old film, bracketing the exposures is important. For old negative, you could make two exposures, one +1 and the other +2.

 

[removed account4]

the best way i have found to deal with speed loss of older film
is over expose it by a few stops and stand develop it in
eyeball measured caffenol c ( with a splash of ansco 130 )
for about 25-30 minutes. i also almost exclusively use expired film.


good luck !
john

 

[newcan1]

Interestingly, with my NPS stock, which I think dates from 2005, there isn't much base fog. The base for didn't increase much if at all when I push processed one stop. But while the negatives increased in density, the grain was still bad. It sounds like the next step should be to shoot at a reduced ISO, maybe 80 or 64. I'll do that and see what happens. I have had luck with other stocks, but I wanted to raise the issue of push processing as it hadn't really occurred to me before. But it seems like it is not really a part of any solution.