From: Jonathan Bailey (quryhous@midcoast.com)
Date: 03/22/01-07:20:33 AM Z
Christina,
> I think the original poster about this topic, about a year or so ago, was
> Jonathan Bailey.
Yes, that's correct: in April of '99 I posted process notes and some
background.
> Then there was a remention in the last couple months, where Judy S. said
>that bleach/etch and mordancage were the same process.
At the risk of seeming contrary, there are a few points upon which I've
remained mute but would like to take the time to comment upon now.
While etch/bleach may be the historic precedent, I believe "Mordancage" - is
a variation of etch/bleach and is creditable to Jean-Pierre Sudre. It's a
very particular process used on modern silver materials. I believe we
discovered in discussion that there were significant differences between
them - including, if I recall, that etch/bleach is a process done to a print
between developer and fix - whereas mordancage is performed on fixed and
washed prints.....
> Anyway, in rereading the posts I saw that Jonathan was interested in
> anything in print on this topic. I have come across, in researching other
> stuff, two mentions of it. One is in Ilford Monochrome Darkroom
> Practice by Jack Coote, pp. 299-304.
This one I was unaware of this and am grateful for the reference.
> The formula in the Ilford manual is 30g copper chloride, 100 ml of
> acetic acid 80%, and water to make 1000ml, with an added hydrogen peroxide
> 20vol just prior to use.
It has also been suggested on the list that substituting drug store strength
H202 for the 30vol/40vol I listed in my posting was just as good. This,
unfortunately, has not been the case in my experience.... Substituting
copper sulfate (was it sulfate?) for the CU chloride listed I haven't tried
yet.
>The Shutterbug article calls Hydrogen Peroxide 20vol equivalent to 6%.
I have never been clear about converting volume measurements into percent
measures. Is there an easy formula?
By the way - Tri-Ess (in Beserk-ly, California) has 100 volume (!) H2O2
which they'll ship (special hazard charge) on days which won't prove to be
too hot. It's $10-12/liter. But I still get my 40 vol from the woman who
cuts my hair - about $8/gallon....
Mordancage is a process I continue to include in my workshops - always with
interesting results. To the best of my knowledge, Craig Stevens is the only
other person teaching mordancage (in this country) at this time. I would be
happy to resend my original posting to the list if there is interest (it is
rather long).
Best wishes -
Jon Bailey
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