[rollei_list] Re: OT Pyro & other developers WAS:Rollei Retro Film
- From: "Jeff Kelley" <jlkphoto@xxxxxxxxx>
- To: rollei_list@xxxxxxxxxxxxx
- Date: Tue, 26 Feb 2008 15:56:54 -0800
All reports I've read indicate that 510-Pyro eliminates most or all of the
problems you mention regarding older Pyro versions. I guess folks are using
it diluted anywhere from 50:1 to 500:1, some with rotary processing, some
with hand-agitation & some using semi-stand development.
We live in interesting times for all sorts of photography....
Jeff
On Tue, Feb 26, 2008 at 12:56 PM, Richard Knoppow <dickburk@xxxxxxxxxxxxx>
wrote:
>
> ----- Original Message -----
> From: "Jeff Kelley" <jlkphoto@xxxxxxxxx>
> To: <rollei_list@xxxxxxxxxxxxx>
> Sent: Tuesday, February 26, 2008 9:37 AM
> Subject: [rollei_list] Re: OT Pyro & other developers
> WAS:Rollei Retro Film
>
>
> > Richard, thanks for the detailed info. You wrote "All
> > ancient history" in
> > your reply but there has been somewhat of a revival of
> > interest in B&W and
> > various newer formulae, especially Pyro variations.
> > For example, 510-Pyro from Jay DeFehr gets rave reviews
> > from most users:
> > ascorbic acid 5g
> > pyrogallol 10g
> > phenidone .25g
> > Triethanolamine 100ml
> >
> > The concentrate apparently has near infinite shelf life
> > vs. other Pyro
> > developers. The above concentrate is mixed 1:100 with
> > water for a one-shot
> > staining developer.
> >
> > I've mixed up a batch but have not had a chance to try it
> > yet.
> > Jeff
> >
> > On Mon, Feb 25, 2008 at 11:22 PM, Richard Knoppow
> > <dickburk@xxxxxxxxxxxxx>
> > wrote:
>
> A curious formua with three reducing agents. There are
> older formulas which combine Pyro and Metol. In these the
> Metol is more a preservative for the pyro than an active
> developing agent. Perhaps the same thing is happening here
> but I wonder what the pyro is supposed to do since Phenidone
> and ascorbic acid form a perfectly effective developer by
> themselves.
> One reason pyro had a bad reputation in the old days was
> the instability of some of the formulas. In particular it
> was common to alkalize using ammonia. Ammonia is volitile so
> the strength of the formula would change day by day. Another
> problem, and one faced by the movie industry after the
> introduction of sound, was that pyro negatives with a stain
> image are very difficult to analyse and control using a
> densitometer. The densitometer must respond _exactly_ as the
> print film does. The introduction of photographic sound to
> movies caused a revolution in laboratory methods because the
> sound must be printed onto the same film as the picture and
> requires very much closer control if the distortion is to be
> minimized. Before sound camera negatives were often
> developed by inspection and one was at the mercy of the lab
> man to get good results. The requirements of sound printing
> and the change to panchromatic film (necessitated by a
> change in the kind of lighting equipment needed for silence
> on the set) changed all this and resulted in the wide
> application of sensitometry and automatic processing. Stain
> images could not be made predictably so negative development
> went from the traditional pyro to M-H developers like D-76.
> With the increase in availability of good M-H formulas and
> tons of research being done on it the traditional pyro
> developers fell by the wayside although they remain
> favorites to this day.
> It would be interesting to compare some of the new pyro
> developers to traditional ones like Kodak D-1 or D-7
> (pyro-metol).
>
> ---
> Richard Knoppow
> Los Angeles, CA, USA
> dickburk@xxxxxxxxxxxxx
>
> ---
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