[pure-silver] Re: Emulsion hardening for reversal processing of 35mm B&W film
- From: Jordan Wosnick <jwosnick@xxxxxxxxxxx>
- To: pure-silver@xxxxxxxxxxxxx
- Date: Sun, 31 Oct 2004 22:28:11 -0500
Richard Knoppow wrote:
> What reversal formulas are you using?
Richard,
The formulas I am using are actually based somewhat on posts you
made in rec.photo.darkroom over the last few years. However, as a
first developer I am using a cobbled-together concoction based on
HC-110B 'spiked' with sodium carbonate to increase activity and
with sodium thiosulfate as a silver solvent. It works well
tonality-wise but your and Nick's posts have got me thinking that
I have maybe brought the alkalinity too high with the quantity of
carbonate I am using.
My rationale in desiging this developer was to use off-the-shelf
HC-110 as a starting material and keep the home-brew to a
minimum. Ilford's documents on reversal processing basically use
paper developer as a base for a reversal first developer, with
added thiosulfate as a silver solvent. I was trying to emulate
this with my HC-110B brew, using extra sodium carbonate to
compensate for the relative weakness of a film soup vs. a paper
soup.
My permanganate bleach is of a standard formula. Bleach clearing
is accomplished with a sodium metabisulfite solution (around 3%
w/v) and 'redevelopment' uses a thiourea solution made alkaline
with sodium carbonate. This gives a nice cold brown tone on Pan F
Plus.
I will try cutting down on the sodium carbonate in my first
developer and increasing dev time to compensate and will report
back on the condition of the emulsion. I realize that modified
D-19 or even Dektol are the standard reversal first dev's (as per
Richard's many posts on r.p.d) but I would like to get this to
work, while avoiding an extra hardening step if I can.
Jordan
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