Lead sheeting won't help. It's transparent to the background cosmic radiation that, cumulatively, will fog film. Rate of fogging depends on film speed and emulsion, with conventional-grain types often less susceptible at a given speed than tabular or core-shell flavors.
Originally Posted by PKM-25
The only thing that will effectively eliminate fog from cosmic radiation is a substantial layer of earth. But make sure there's no granite in that layer. I've often thought that the underground refrigerated storage offered by this outfit
would be optimum, but am afraid to even ask for a quote.
Tri-X in sheets is one of those higher-speed films that lasts very well in long-term frozen storage, suffering only a very gradual increase in fog. One can lower the exposed speed over time and simply print through the fog, being left with a perfectly usable EI 250 film (rotary, ID-11 1:1) even after decades. Fresh, that combination yields a 0.1 over fb-f EI of 500; I shoot it at 250 anyway to get off the toe, so don't anticipate any change in my shooting routine over time.
Given already announced Kodak discontinuations, not to mention probable imminent bankruptcy, I decided a dedicated film freezer wouldn't be worth the floor space, cost (acquisition and energy) or trouble for me. Instead, I negotiated with my wife to "split up" volume in the freezer compartment of our regular refrigerator-freezer. Then I concluded that, for the most part, 5x7 320TXP was the best film to bank.
As a result, I removed an inner door and shelf in the ice tray area to accommodate even more boxes than were already cached. There are now 1,800 sheets of 5x7 and 100 sheets of 8x10 320TXP in the freezer. An additional 126 sheets of 5x7 remain in the refrigerator compartment. And we can still store all the food our cooking/eating habits require. Seems like a good compromise, especially since I haven't found any film that better matches the thousands of sheets of Azo I stockpiled when that final batch was sold. As an amateur who is 14 years older than you and shooting much less, Dan, I'm considering this a lifetime supply.