Re: expiration dates on film boxes

From: [email protected]
Date: 10/14/05-07:41:21 AM Z
Message-id: <101420051341.14997.434FB57F000EB4F000003A9522007503309B010C9C0B020E049708@comcast.net>

Would freezing film prevent age related emulsion fog?
I have several boxes of super XX 8x10 film that has been in the freezer since the mid 1980's. I always thought that I would one day go out in a blaze of glory with my old Deardoroff and that stash of film. :-)

Jonathon Russell

--
"Expose for the secrets,
 Develop for the surprises!"
> From: Richard Knoppow <dickburk@ix.netcom.com>
> Subject: Re: expiration dates on film boxes
> Date: Thu, 13 Oct 2005 13:12:51 -0700
> 
> > I have recently been using up some 4x5 film that is probably at
> > least 15 years old. Some shows some fog but some does not. The fog
> > is cured by adding a little bromide to the developer. The main
> > change in most film is the accumulation of fog. While this has a
> > practical effect of lowering speed (as does adding bromide or
> > benzotriazole) contrast seems not to change too much and I generally
> > give more exposure than the ISO speed calls for anyway.
> 
> One must distinguish developer fog and emulsion fog. Age-related fog
> is emulsion fog, which reacts with developer much like lightly exposed
> grains. Trying to salvage those emulsions by adding bromide or
> benzotriazole is usually a wate of effort, possibly except very early
> point in the fogging.
> 
> Use of restrainers or antifoggants do not necessarily come with speed
> loss. Studies by Hillson of Kodak HArrow in 1970s showed that
> simultaneous addition of antifoggants and powerful development
> accelerator could enhance discrimination of exposed and unexposed
> grains. He added 5-methylbenzotriazole and CD-2 to DX-80 developer,
> among other conditions. He also used Plus-X in modified D-19 and D-8.
> In those cases he demonstrated significant speed increase by adding
> 5-MBTA. He proposed that the enhanced discrimination could be achieved
> by prolonging induction period and accelerating rapid development
> phase at the same time.
> 
> The results are very interesting, but I am not sure about the
> completeness of the proposed mechanism, in light of more recent
> results. I am also not sure about the extent it is applicable to good
> pictorial b&w film developers. (Good pictorial FILM developers are
> designed to develop grains in parallel development mode, but D-19 is
> quite far from this mode of development.)
> 
> Anyway, I just wanted to point out that addition of antifoggants does
> not necessrily entail in loss of speed. 5MBTA is more powerful
> antifoggant than usual benzotriazole. (Unsubstituted benzotriazole is
> too weak to be effective in developers containing  p-pd derivatives.)
> 
> >    BTW, I am not enthusiastic about development by 
> > inspection.
> 
> Agreed. Development by inspection was the common practice before
> accurate thermometer and light meter were easily accessible to
> photographers.
> 
> > Overexposed negatives are not much of a problem because modern film
> > has tremendous overexposure latitude but the ISO method gives just
> > about the minimum exposure for reasonable shadow detail so there is
> > very little latitude on the underexposure side.
> 
> I have a paper describing the calibration of Weston incident meter,
> and another paper describing the rationale behind the change in ASA
> standard of negative film speed. Having read them, I understand that
> they made effort to make a scientifically sound industrial standard,
> but at the same time, there is no one calibration standard that works
> for all applications.
Received on Fri Oct 14 07:41:37 2005

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