mordancage

["Christina Z. Anderson" <zphoto@montana.net>]

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