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Photography Question 

Kyra Kverno
 

deep freezing exsposed film


Deep freezing exsposed film?


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August 04, 2001

 

John A. Lind
  Kyra,
The difference between exposed and unexposed film is the presence of a "latent image" on the exposed film. If film is to be processed soon (within a few weeks), refrigeration is more than sufficient. Follow the freezer precautions below with refrigeration too.

In general "deep freezing" will not hurt the film or the latent image on the film. Two precautions:
a. Save the cannisters and seal the film in them before freezing, or even refrigerating it. This prevents condensation of moisture on the film (which can cause spotting).
b. Allow film to warm to room temperature for a several hours before opening the storage container(s) for processing. Don't try to speed this up by heating it above room temperature.

While "deep freezing" exposed film will slow down emulsion chemical changes to nearly dead stop, there is another major issue with very long storage of exposed film (measured in numbers of years). It has nothing to do with temperature or humidity. Background gamma radiation does affect film. This is not something that can be shielded against. Lead containers won't stop it, and it eventually fogs the film. How long this takes depends on the emulsion, its speed and how long it is stored prior to processing. I mention this issue only becuse you didn't state what film speed you're dealing with or how long you intend to store it. This is not something to worry about for even months of storage. At background radiation levels it can take numbers of years for the effect to become evident. (The effect of this on unexposed film is generally a slight drop in film speed and slight increase in granularity).

-- John


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August 04, 2001

 
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