From: Judy Seigel (jseigel@panix.com)
Date: 07/29/01-11:43:11 PM Z
On Sun, 29 Jul 2001, Christina Z. Anderson wrote:
> Came across another reference to bleach/etch/mordancage. It is in Darkroom
> Basics and Beyond by Hicks and Schultz (2000, p. 116-118). They recommend
> buying a readymade bleach etch solution by Fotospeed or Tetanal instead of
> mixing one's own, which to me is not necessary as it is easy to mix the
> solution oneself, and not terribly pricey.
Bad idea for many reasons, including death of the hydrogen peroxide in
time once it's used, and a factor of about 5000% in cost.
> Anyway, there are some examples of the different effects produced by
> the process in relation to whether one does it in room light or under
> safelight, *before* fixing. Under roomlight, with the redevelopment after
> bleach/etching, you get a solarized image. Under safelight you have the
> traditional etch look that looks negative. Neither have the mostly positive
> wavy emulsion attached that is part of the mordancage look. But the idea of
Chris -- that's only "part of the mordancage look" as practiced by certain
contemporaries, a kind of *mannerism* if I may say so (and even if I may
not) that has NOTHING to do with the original process. Christopher
James's book shows 2 beautiful Jean Paul Sudre mordancages that are
perfectly unruffled and one by Opalenik ruffled to a farethewell.
> solarizing it in the process is appealing.
> Anyway, just thought, Jonathan Bailey et al, you might be interested in
> this other reference. And, someone on the list said that one could
> substitute copper sulfate for the copper chloride required in the bleach
> etch solution. Is this true? I ordered a lb of copper s. and it is about
Yes it's true. Don't you trust me? I did it with both, found no
difference (except as you say the price). It's possible there's enough
chlorine in tap water to suffice -- or some other reason. I didn't make up
the idea, tho I can't remember where I got it...
> $8, compared with copper chloride that is about $90 (gasp) for the same
> amount, and will test it, but if some chemist could tell me why the two
> would be interchangeable I would appreciate it. OH, and also (my chemistry
> disability will now show more) what exactly is the dif between sulfate and
> sulfite and are they weight for weight and in all other details exactly
> interchangeable?
I suspect in some you can use either, as potassium bisulfate can be used
instead of potassium bisulfite or metabisulfite (or vice versa) and/or
sodium sulfite (tho I doubt sodium sulfate) for clearing gum, but I doubt
most. Of course if there's someone on line who knows for sure, I take that
back. (Which ones were you thinking of?)
Judy
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