Re: expiration dates on film boxes

From: George L Smyth ^lt;[email protected]>
Date: 10/14/05-09:49:52 AM Z
Message-id: <20051014154952.5390.qmail@web33206.mail.mud.yahoo.com>

Chances are that the answer is yes. I do not have film that old, but am still
using Konica IR that expired in 1992 - no trace of age at all.

Cheers -

george

--- hylandscot@comcast.net wrote:

> 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.
>

Handmade Photographic Images - http://www.GLSmyth.com
DRiP Investing - http://DRiPInvesting.org

        
                
__________________________________
Yahoo! Mail - PC Magazine Editors' Choice 2005
http://mail.yahoo.com
Received on Fri Oct 14 09:50:19 2005

This archive was generated by hypermail 2.1.8 : 11/07/05-09:46:19 AM Z CST