Re: Wet HIE Film Boxes

["Willem-Jan Markerink" <w.j.markerink@xxxxx>]

On 24 Dec 96 at 18:32, Robert Long wrote:

> It sounds very much as though some unknowledgeable person wrapped the
> boxes in plastic at room temperature before stowing the lot in the
> freezer.  Given a good seal, this will inevitably cause
> condensation--very heavy condensation unless the ambient humidity is
> extremely low--on the inside of the plastic as the contents cool.  The
> condensation then freezes, and this frost melts to water, rather than
> vapor, when the package is removed from the freezer, soaking the boxes
> as you describe.  Even without the plastic wrap, my boxes get that way
> in my home freezer.

Sorry to pick on this again Robert, but cold temperatures only do not 
cause excessive condensation/sublimation.
I thought long and deep for a good example, the best one I could 
think of is when you park a warm car out in a cold freezing night.
All frost ('ripe'?) is formed on the outside, never on the inside, 
not matter how cold it will be. Only if you stuff a bunch of warm 
sweating people inside the cold car, inside frost will occur.
I also believe the dew point is measured/calibrated in an open space, 
never in a confined space of a certain size (in which a perfect 
sphere would have the least surface with the most content, any other 
shape would decrease the occurrence of dew by offering relatively 
more surface to spread the moisture). 

As another example: most of my film is packed in a flat plastic
Tupperware container in the freezer; opened up frequently, thawed up a
few times a year for holidays, and some boxes with odd film have been sitting in 
there for years. None of it ever got wet at all.

Again: real nasty condensation only happens with a steady supply of 
air, which dew point is higher than the cold object you are putting 
into it. A sealed container will not create nasty condensation.

Heck, I would otherwise even get problems when dark loading and 
changing HIE while skiing. It can get pretty damp in such a 
changing bag, and you do seal the exposed film with quite damp air, 
while it very likely faces sub zero temperatures again (I went close 
to -20C this year, with a gnarly stormy wind on top of that....never 
had to whack my fingers as hard as this winter to get blood back in 
after a few minutes of shooting....<shrugg>....I only hope those 
shots were worth the torture....8-))
 
> A dealer once told me that film, like meat, should never be re-frozen
> and pointed out that gelatine is a sort of meat product.  One thing
> I've learned from this mailing list is that the advise was hogwash.
> Willem says he regularly takes film from the freezer in anticipation
> of use and then puts it back when it's unused.  (Of course he doesn't
> break the inside seal, I'm sure.)  So just put what you won't need for
> immediate use into your own freezer, and the film itself should be
> good almost indefinitely, whatever the condition of the packaging.

I have thrown opened cannisters back in the freezer as well....8-))
Mostly exposed film though, can't think of ever having (almost) 
loaded a film and decided to throw it back in.
Remember: exposed film (latent images) are even more affected by 
temperature than unexposed film, so refreezing makes even more sense 
if you can't develop immediately. This goes for both normal and IR film!
I believe where unexposed film only/mostly suffers an EI decrease 
from heat, exposed film also suffers from a decreased contrast. 

I also can't believe that Ektachrome IR is never thrown back into the 
freezer, whereas it needs -18 to -23C as unexposed film (the color 
balance/calibration for scientific use is probably the largest reason 
to do this anyway; b&w isn't affected by color deviations).

--
Bye,

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     _/  _/ illem    _/     _/ an    _/  _/  _/ arkerink
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      The desire to understand 
is sometimes far less intelligent than
     the inability to understand


<w.j.markerink@xxxxx>
[note: 'a-one' & 'en-el'!]

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End of INFRARED-PHOTOGRAPHY Digest 168
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