Re: Exposed film+age=degradation

[P3D Dave Worrell <dworrell@xxxxxxxxxxxxxxxxxxx>]

Yes indeed ... un-exposed film, when kept frozen,
experiences very little degradation. Frozen film will give
good results for years after it expired. I've had excellent
results buying expired film from pro shops (that keep their
film refrigerated) but I wouldn't buy expired film from the
local drugstore.

But, as earlier posters pointed out, once film has been
exposed it degrades rapidly. I assume the light starts the
image forming reaction (latent image) at exposure. The
longer that reaction has to go on, the worse the final
image will be. Cooling and/or freezing may slow the
reaction but short of cryogenic freezing (-300c/f) it will
still occur.

But speaking of cryogenic processing - a guy has set up
shop providing cryogenic processing of just about anything
(mainly steel tools). Claim is that freezing, very slowly,
to -300 causes molecular alignment to become smoother.
Result (if testimonials are to be believed) that cutting
tools become sharper and that the edge lasts longer, and
that nylon stockings wear out before running ... But, to
get back to the photographic angle ;-), I know astronomers
freeze their plates to improve sensitivity (or did before
CCD technology). Any thoughts on if this cryogenic
processing could help standard films? The guy charges by
the pound so it shouldn't be too expensive. Perhaps this
would allow Kodachrome results for Sensia prices?

Dave Worrell (dworrell@xxxxxxxxxxxxxxxxxxx)
Publications Technician
State of Alaska
Section of Epidemiology


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