From: Nate Apkon (nmapkon@rcn.com)
Date: 09/22/02-05:51:26 PM Z
Chris:
Just got back from a day at a massive Boston "open studios" followed by
dinner & a couple of martinis...so I need to think more about what you
say in your email when my mind is clearer. However, I did spend all
day yesterday doing Mordancage using the Cootes formula with extensive
(15 min.) washed between steps, and using LPD 1:6 as the redeveloper.
After redevelopment I used stop bath and then fixed according to my
usual B&W procedures. I got absolutely no staining. All the white
areas remained pure white, while the areas where the gelatin was removed
turned a uniform cream color. I did find that I could achieve a
beautiful deep purple (like selenium split toned) by pulling the print
from the redeveloper before it was fully developed and immersing in stop
bath asap.
BTW, I found the Cootes formula much more active than Craig's/Jon's and
had a much longer "shelf" life and capacity. I also love your simple
mixing approach.
I'll think more about what you said & get back to you tomorrow.
Nate
Christina Z. Anderson wrote:
> I continue to test mordancage. Now I am into pitting different
>formulae against each other, and I found out a peculiar thing.
> Cor, Nate, perhaps Jon, and I and maybe others on this list a while
>ago were wondering how to avoid the stain that occurs on the paper from the
>process, even in the borders of the print. I had previously posted my test
>results that to get clean whites do the process a) under safelight, b) with
>lower volumes of peroxide c) fix afterwards d) avoid chemical stain that
>occurs when a print thru the mordancage solution is not cleaned enough of
>the chemicals before it goes back into the developer by proper washing.
>These still stand, in my opinion, and certainly for Coote's formula, but I
>was interested in maybe prioritizing which ones are the bigger culprits. I
>also cannot stand the fixing after the mordancage because it is so grossly
>smelly when the fixer combines in the print with residual mordancage
>chemicals. Sometimes a lengthy washing is not an option as the emulsion is
>fragile.
> But yesterday I was testing Clerc's formula against the one that I
>always use, Coote's. Here are the two:
>Clerc
>cupric chloride 10g
>citric acid 10g
>water to 1 liter
>Mix with equal volumes 10 vol hydrogen peroxide (3.4%).
>
>Coote:
>30g cupric chloride
>80 ml glacial acetic
>water to 1 liter
>Mix equal parts with 20v to 40v hydrogen peroxide.
>
> Clerc's was a very gentle formula, and didn't smell half as bad. (BTW,
>I did try copper sulfate again with citric acid, and still no go, but I have
>ordered some stronger acids to test it with. It would be nice if it would
>work because it is a buck a pound at a ranch supply store, but it is always
>in combination with nitric, sulfuric acids). It did not bleach much at all,
>which was fine for me as I don't care that it bleaches, took longer to do
>its thing, and is rubbed under hot water (90 degrees). But it was really
>nice to use and gave great results, one being NO staining of the whites,
>even under room light.
> I tested to see if it might be the acetic vs. citric, and it still
>didn't stain. I tested going right from mordancage to developer without
>washing and got some stain that *looked* like normal chemical stain. But
>this is my thought: there may be three reasons why no stain with Clerc's:
>the *warm* water rub effectively cleaned out enough of the bleach solution
>to not get chemical contamination, in effect, a more effective washing
>between steps, or the lesser amount of cupric chloride, or the lesser
>strength hydrogen peroxide.
> Then it dawned on me as this may be the greater possibility, since I am
>also testing mordants with dye mordanting. I realized that the stain of the
>print only occurs in the gelatin areas of the print, including the borders
>of the print. The areas where there is no gelatin do not stain. Hence,
>could it be that the culprit is the stronger amount of cupric chloride which
>in effect acts as a mordant to the gelatin which then makes all gelatin
>remaining attract developer? In combination with the stronger hydrogen
>peroxide which destroys more of the gelatin and therefore making it more
>permeable to chemical stain? I would have to retest Clerc's with 1) stronger
>hy per and 2) stronger cupric against the original to get my answer, but
>those of you who have the time should test Clerc's and see what you get,
>too. My process was to print a print a bunch of times and then use the same
>print from the same batch to compare.
> Whatever the case may be, those into mordancage may want to try Clerc's
>formula and see if you, too, do not get stain. Maybe you could save me lots
>of time and test these two variables for me :) Right now I am so sick of
>copper up my nose I could puke. And Peter Marshall, any chance I may see
>McFaden's article?
>Chris
>
>
>
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