Re: mordancage

[Thom Mitchell <tjmitch@ix.netcom.com>]

Maybe I came in late but for us new to Alt. what is mordencage? Obviously I
am fascinated by the possibility of producing a neg or a pos from the same
print. Can you simply discuss why someone would use the mordencage process?
Thanks, Thom
----- Original Message -----
From: "Christina Z. Anderson" <zphoto@montana.net>
To: "Alt Photo List" <alt-photo-process-l@sask.usask.ca>
Sent: Monday, May 20, 2002 19:30
Subject: mordancage


> OK, so it's taken months to get back into testing this again but here is
> what I found.  This week I tested this and stand development (reported
that
> to the pure silver list).  I took two of the exact same print and paper
and
> side by side used the copper sulfate/citric acid/potassium bromide mixture
> next to the Jack Coote formula out of the Ilford book.  By far the Jack
> Coote formula is superior.
>      First of all, you can mix up the formula and let it sit for months
and
> it keeps on tickin'.  (1000 ml water with 30g copper chloride and 80ml
> glacial acetic acid).  Just before use, mix it with 20v or 40 v hydrogen
> peroxide, equal vol.  It doesn't require heat.  It bleaches immediately
and
> immediately eats the emulsion.  You can see the emulsion all mushy and
> bubbly in the dark areas.  If you want to make the image a negative of the
> positive, you rub the whole print off.  If you want to keep it positive,
> don't rub.  In both cases, redevelop in Dektol or toner.  OR, do a half
> neg/half pos with half rub.  The highlights remain mostly unaffected so
will
> continue to be positive.  One time thru the bleach and developer is plenty
> enough.
>      The other formula did make the emulsion fragile but even with a
> scouring sponge it did not all come off.  It was more work than it was
> worth.  I think I just need to adopt the adage, "if it ain't broke don't
fix
> it", even if the copper sulfate is cheaper by far than the copper
chloride.
> With Tri-Ess Sciences (thank you, Jonathan Bailey) the copper chloride is
> cheap enough by the pound to not be a huge expense.
>      The other thing I noticed, side by side, was the redevelopment in
> normal Dektol brought the image in the Coote formula back to full density,
> but the other image did not come back to full density. This could be a
> fluke, but it would seem that a mordancage of that formula may require a
> darker print.  Since i did both prints at exactly the same time, same
> developer, same density, I kind of don't think it was a fluke.
>      The copper sulfate/citric acid formula was the one that Peter
Marshall
> found in an old Amateur Photographer magazine.  I notice from the number
of
> other formulae I have on mordancage that usually copper sulfate is
combined
> with acetic or nitric acid, and copper chloride with acetic or citric.  I
> have about 10 formulae I have come across all told, some I have discarded.
>      I have tried to start up convos with people off list about mordancage
> but no replies to those I emailed--they obviously weren't interested in
> sharing trade secrets :) and obviously I don't believe in trade secrets.
> Jimmy Peguet, you did say you took a class from Sudre--if you are willing
to
> correspond, please email me offlist.
> Chris
>
>