From: Sandy King (sanking@clemson.edu)
Date: 11/29/01-05:43:12 PM Z
I sent this already two times but received error messages so don't
know if it went to the list or not.
Sandy King
Linas wrote:
> I think we are definitely over
>staining and perhaps sometimes overexposing for the way we develop. As I've
>told you off list, I've started using Pyrocat and really like these
>negatives for Pd/Pt. Same "pyro look" to the prints, but less overall stain
>and shorter print times.
I am certainly guilty as charged. As I have said before, overexposure
of negatives that are to be developed in a staining developer for
alternative printing should be avoided like the plague. When you
overexpose by a stop, even with non-staining developers, you can
expect that this will translate into about a doubling of your
exposure in printing. This changes a 10 minute exposure to 20
minutes. It gets even worse with staining developers - you get the
doubling of exposure, plus proportionally more stain *in the shadow*,
so the net impact on exposure is even greater. This happens because
it is primarily the shadow density that determines printing speed
with developing out processes.
If you have any question about whether or not your negatives are
over-exposed, measure the density in Zone III, the first shadow zone
where we typically like to see shadow detail. If this Zone measures
over log 0.30 you are almost certainly over-exposing. Even with films
that have b+f like HP5+ and BPF we should be able to keep the density
of Zone III at about 0.30 or below. With a Zone III density of 0.30
my carbon negatives with the BL bank print in about 10 minutes, not
bad.
Should I happen to overexpose HP5+ or BPF by a full stop, Zone III
density will increase to approximately log 0.55 and printing
exposures to about 30 minutes. The net impact on printing time is
less with a film like FP4+, when with correct exposure I expect to
see a Zone III density of about 0.20, but even with this film
over-exposure by a stop results in more than a doubling of the
printing time.
However, the stain itself, with the correct exposure, is highly
desirable for alternative printing since it helps to bump up the
contrast to the desired CI with less development time, or in flat
lighting situations allows us to make a printable negative when
otherwise we could not. What we want, though, is very little stain in
the shadows and a lot in the highlights. Lots of general stain,
caused by over-agitation or oxidation, is very bad because it
actually reduces contrast.
I find that PMK is very prone to a general stain caused by
over-agitation and/or oxidation, plus it has a history of streaking
and staining. Given these problems, and the fact that it takes so
much development time to reach the density range we need for
alternative printing, my personal opinion is that PMK just does not
make much sense for processes like carbon, Pt/Pd, kallitype, and
vandyke that typically require a negative with a DR of 1.4 or higher.
ABC+ or Pyrocat-HD make much more sense to me.
Sandy King
>
>Remember how Bob Herbst said he doesn't use an after bath, uses normal
>Kodak Fix, and even an acid stop bath (if I recall correctly)? Seems he is
>actually making an effort to minimize stain. However, still plenty of stain
>on his Wimberly WD2D negs, based on the ones he showed me after his lecture.
>
>I'm looking forward to what Carl Weese has to say about Pyrocat after he
>tests it.
>
>Linas Kudzma
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