[pure-silver] Re: Was Old paperandDefender... now The Hows and Whys Qiuz Show for Dummies: Whats the Mechanism?
- From: Ray Rogers <earthsoda@xxxxxxxxx>
- To: pure-silver@xxxxxxxxxxxxx
- Date: Sat, 1 Mar 2008 23:16:19 -0800 (PST)
--- mail1 <mail1@xxxxxxxxxxxxxxxxx> wrote:
>each form of reduction has different formulations of reducers,
>and these differences change the mechanism of reduction.
Jonathan,
Yes...
and I have not looked at the problem from that side yet.
Obviously, that will help.
I will consult Mees (which edition do you have?) but I dont recall the
mechanism of how the bleach
differentiates being addressed so I was just trying to think it through
logically.
Ray
> >> The three classifications of reduction or the removal of
> >> silver from the
> >> photographic image are.
> >> 1. Subtractive. Reducers of this type remove equal amounts
> >> of silver from
> >> all densities there by increasing the density range of the
> >> negative.
> >> Subtractive reducers improve over exposed negatives, and
> >> positives, or for
> >> removing fog.
> >> 2. Proportional. Reducers of this type remove from each
> >> density an amount of
> >> silver which is proportional to the original density.
> >> Proportional reducers
> >> are a means of reducing excess density and contrast due to
> >> overdevelopment.
> >>
> >> 3. Super Proportional. Reducers of this type remove a
> >> greater proportion
> >> from the higher densities than the lower densities. This
> >> type reduces
> >> density of overdeveloped negatives of contrasty subjects.
> >>
> >> Photographic reduction is a process of oxidation where the
> >> reducer converts
> >> the metallic silver into a silver compound which is
> >> soluble in water, in an
> >> acid, or other suitable solvent.
> > These are good definitions but do not address the
> >_mechanism_ by which the reducer discriminates density. I
> >don't remember seeing this addressed in any of the theory
> >books I have but it may well have been in newer
> >publications. It just simply never occured to me to wonder
> >about it before.
> >
> >---
> >Richard Knoppow
____________________________________________________________________________________
Be a better friend, newshound, and
know-it-all with Yahoo! Mobile. Try it now.
http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ
=============================================================================================================
To unsubscribe from this list, go to www.freelists.org and logon to your
account (the same e-mail address and password you set-up when you subscribed,)
and unsubscribe from there.
Other related posts:
