RE: palladium bleedoff

There was a long thread about this topic back in May on the APUG Alternative
Process Forum.

http://www.apug.org/forums/showthread.php?postid=310901

Some folks mentioned that they have had the problem occur with several
different types of paper including Platine, Cot320, Cranes Cover 90 (a.k.a.
Birdcageotype in Placerville, CA) and possibly others. In the end, nothing
definitive was resolved as the exact cause of this problem.

I've also experienced this problem with iron-silver processes such as VDB
and kallitype using different papers at various RHs.

My best guess is that the amount of sensitizer used can cause this,
specifically using more than is really needed. I've also noticed that this
problem will crop up when printing negatives that have a lot of dark tones
near the edge of the image but the bleeding can be observed in any part of
the image where darker tones occur.

I inquired about this problem quite a while ago when printing VDB. So far as
I know no one has solved the issue.

I do recall that Mike Ware discusses a similar issue of bleeding using the
traditional cyanotype formula in his cyanotype book. If memory serves me
well he referred to this as peptization (peptisation) but may not be related
to palladium printing.
 
Don Bryant

-----Original Message-----
From: Christina Z. Anderson [mailto:zphoto@montana.net]
Sent: Monday, July 10, 2006 10:36 AM
To: Alt, List
Subject: palladium bleedoff

Hi All,
Back from assisting the Bruce Barnbaum workshop at the Photographer's
Formulary. What a hoot. Great sense of humor, that guy, and all of a
sudden my black and white prints don't look so stellar to me anymore :)

Back to alt this week: I've never seen this issue until this month,
although I have read about it on the list and kept notes as to its causes
(don't use Crane's Cover bright white, too rapid drying, too much metal
salts...). So this month I've been making prints my exact normal way, on
the same paper (Arches Platine), everything. The bleeding is only coming
from the dark border edges of the print and is not affecting the image
density at all.

The only thing that may be different in my practice is the humidity is
higher here in the summer--all of 42% (and once I saw it at like 50%!)
instead of 20-35%! Except that should be a plus for this problem, not a
minus. I do let the print dry for 20-30 minutes, air dry.

And I did a perhaps no-no: I was running out of am citrate developer so I
had a jar of sod citrate on hand and mixed up that and mixed it into the am
citrate. Could that be the problem, the two citrates mixed? Otherwise am
citrate does great for me.

What is even the difference between an ammonium and a sodium salt of a
substance?

Does anyone mix Tween in with their sensitizer? I know Michael Kravit mixes

PVA 10% goo, 2 drops into 5ml...

The last possible idea is that my former palladium solution--purchased--had
less metal salts in it than my current palladium solution which I mixed
myself...but that shouldn't be the case, correct? I mean, isn't all
palladium mixed at the same strength (5g to 55ml)? I sure am getting nice
blacks, though!

Too many questions I am sure...but it's ohhhh so fun when you pt/pd guys
start talking.
Chris
Received on 07/10/06-04:23:35 PM Z