From: Christina Z. Anderson (zphoto@montana.net)
Date: 03/01/02-07:08:36 PM Z
Robert,
I have been on a mission all year to find out all the info i can on
this process. It goes by various names, bleach/etch, mordancage, and then
of course the formula used with bromoil. Judy Siegel, Peter Marshall, and
Jon Bailey on this list have graciously supplied me with formulae to try.
All three have taught/teach it in their photo classes.
Every formula I have either has copper chloride or copper sulfate in
it, along with various other ingredients. All use hydrogen peroxide, too.
I also got several names of other practitioners of the process and have
contacted them by email to see if they would correspond with me but so far
no replies back. Oh well.
The bleach/etch formula basically eats away the dark areas of the print
and then etches the highlights, so that if all the gelatin is rubbed off it
will redevelop into a negative image, with the possibility of leaving stuff
unrubbed and therefore having a positive image or part positive/part
negative. If it is not strongly acid, the dissolution of the gelatin will
not happen. I have not read of any other metal salts working. However, I
have only found about 9 or 10 sources that even mention the process. I can
send you some info offlist if you would like...attachment file.
Chris
> Dear All,
>
> I've been using an etch-bleach bath of peroxide and cupic chloride.
> Anyone have any idea how it works? Might other metal salts be effective?
> Are there other etch-bleach baths that, like this one, attack the gelatin
of
> the emulsion itself?
>
> Robert Schaller
>
> on 2/27/01 9:03 PM, Judy Seigel at jseigel@panix.com wrote:
>
> >
> >
> > On Tue, 27 Feb 2001, Jeffrey D. Mathias wrote:
> >> ... However, hydrogen peroxide is also
> >> sometimes used as a contrast agent with some alt-process coatings, and
> >> in this use accurate knowledge of the solution strength is required for
> >> consistent results.
> >
> >
> > Well that figures... Only one I've heard of, BTW, is for some pt/pd
> > coatings. Are there others?
> >
> > Judy
> >
> >
>
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