Potassium Oxalate developer for Platinum printing

Hi,

I have been using a 25% solution of Potassium Oxalate as my developer
for Platinum printing (no Palladium added), and to my surprise this
developer went "off" rather quikly. That is: in the 500ml I started with
I could process only 5-7 8*10 images (did not keep exact count). My last
print showed veiled highlights, which did not want to clear, and the
PotOx solution is now very murky with a greenish brown strong colour.

I looked into dome books as well as in the archives, and the things I
find are contradicting (no surprise I guess). Crawford (and Farber who I
think quotes Crawford) claims that the developer keeps indefinitely, and
has only be toped up with fresh developer to make up for the loss. It
actually gets better when it's more used. James states about the same,
although he says that there is an end to the live of the developer.
Jeffrey Mathias advices to use the developer single shot, reusing will
cause fog..

Single shot seems a bit wasteful, as well environmental unfriendly with
this toxic chemical, OTOH 6 8*10 prints with half a litre isn't exactly
economical either, plus the ruining of the last print.

Can one use a lower concentration of PotOX, develop longer and discard
it afterwards?

I did try brush development with glycerol: PotOx 1:1, but I wasn't very
successful with that, got a lot of developer lines, will brush
development also work with FO, I have only read about it connection with
AFO.

Comments or suggestions/

Thanks!

Cor
Received on Mon Apr 24 17:25:45 2006