expired/2003 Agfapan 25 (120)

[karin bingel]

I have over 120 films Agfapan 25 (120) which expired in 2003, kept at -25
Celsius since bought, victims of having started to use Delta 100.
I shot two films yesterday and the film seems to be perfect.
Can I expect them to last a few more years or should I try to sell them instead? I shoot exclusively 6X17 and Delta 100 is way more flexible due to higher speed.
Thanks

 

[Ed Sukach]

-25 degrees Celsus is a significantly LOW temperature. I would expect the film to last ... oh ... something like one hunrded years, or so.

What is involved is "Chemical kinetics" ... and the Arrhenius equation would seem to be appropriate in calculating a more coherent shelf life than I described above.
A useful generalization: (In) "Many reactions which occur near room temperature, an increase of 10 degrees Celsius approximately doubles the rate of the reaction." So, in reducing the storage temperature, the shelf life is increased. Given 20 degrees Celsius as usual room temperature, shelf life will be ~ doubled at 10 degrees C; doubled again at 0 deg. C; doubled again at -10, again at -20, yet more at -25. If the usual shlf life is five years, we are near the 100 year mark at -25.

I've worked with the Arrhenius equation, and related, in Reliability and Environmental testing. We had a nice, neat little computer program - put the temperature, and other significant factors in, and projected "Life" information would come out. Unfortunately, I don't have access to the program any more ... so, possibly someone else here (Listening, PE?) would care to be more accurate.

You might want to try Arrhenius/ Arrhenius equation through Wikipedia.

 

[Jayd]

Film kept dry and frozen seems to have a near endless life span. I have 2 year old konica color that works perfectly and I recently found some TriX tucked away in my freezer that expired in 1983 if I had tank processed it there would have been no problem but I sent it to a local lab and the rollers on their machine pulled some of the emultion off. This could hav ebeen incompatibilty of chemistry of some fault other than the film but I would suggest on very old fim tank processing it following instructions for the time the film was current as both film and chemistisrty change. If you think you will use it keep it , but there are people including me who would like to have it and belive it or not film sells very well on ebay and I would suppose here .
Jay

 

[jim appleyard]

How much would you like for the film?

 

[PhotoJim]

Films like these will keep fine for many more years.

The higher the light sensitivity (i.e. the higher the ISO), the less long you can keep the film. Cosmic rays are constantly bombarding the Earth, and silver compounds in the emulsion are slowly fogged by them. In the case of APX 25, this happens exceedingly slowly. In the case of Tri-X the damage will be apparent in a few years (the results might look good but if you compare them to fresh film you will see that the base fog levels are higher). In the case of extremely fast films like Delta 3200 or T-Max 3200 the damage happens quite quickly and even a year or two out of date, well frozen (<-17 C) there will be significant fog.

Now, you can print through fog... and you can shoot at a lower EI to make up for it to some degree. But the film will not shoot like fresh film.

In my experience, ISO 400 seems to be where storage life starts to get limited. Under that, I can keep film stored for many years in my deep freeze (some call it a chest freezer) and not have any noticeable change in performance. 400-speed films like HP5 Plus and Tri-X will keep and be very usable but I don't push it more than a couple of years past date. Really fast films, I try to use before expiry date. (I have even noticed that brand new very fresh Delta 3200 has noticeably less base fog than frozen, near-but-still-before-expiry-date Delta 3200.)

 

[karin bingel]

Thank you for your enquiry, the film is in Athens (Greece) and I shall despatch only to a European Union
country. Price is ... what you consider to be fair if you are satisfied + carriage (30-40 euros).