RE: Potassium Oxalate developer for Platinum printing

Cor,
I do not print pure Pt, but in my experience of palladium/platinum mix the
developer lasts forever. I just replenish what was is lost in a development
session. Do keep your developer acidic, as it will fog the paper otherwise.
If you use buffered papers that might require even more oxalic acid
replenishment. I keep mine developer with some undissolved acid on the
bottom.
Le tus know how you solved your fogging problem.
Marek, Houston

>From: Eric Neilsen <e.neilsen@worldnet.att.net>
>Reply-To: alt-photo-process-l@usask.ca
>To: alt-photo-process-l@usask.ca
>Subject: RE: Potassium Oxalate developer for Platinum printing
>Date: Mon, 24 Apr 2006 20:34:59 -0500
>
>Cor, Your developer will hold onto a portion of your coated area that was
>exposed and not part of the print. This coated and very slightly excited
>area will become part of that 500ml; which seems really skimpy to me by the
>way. There are also buffers in the papers that can adversely effect your
>developer. While you may only need 500ml to cover your paper, I'd advise
>you
>to use a larger amount as a stock solution. If the cost of Potassium
>Oxalate
>powder is high in your area, I would make it from Potassium Carbonate and
>Oxalic acid. Pour out the amount need to develop your print, and after pour
>it back.
>
>You can also use Oxalic acid to keep your developer on the acid side of
>life. You may also find that exposing your developer to UV light and
>letting it sit, will allow you to remove the excess metals from your
>developer. The greenish quality is not a problem. Single shot eliminates
>the
>chance of fog due to removed components from previous prints, but I don't
>find it necessary.
>
>You can use a lower concentration of Pot ox but you run the risk of
>graining
>up your prints. You will also need slightly more exposure.
>
>I have only tried brush development a few times, but I would look into a
>good even pour ,just like for coating the sensitizer, and a quick even
>dispersal of the coating, perhaps even by using a rod.
>
>Eric
>
>Eric Neilsen Photography
>4101 Commerce Street
>Suite 9
>Dallas, TX 75226
>http://e.neilsen.home.att.net
>http://ericneilsenphotography.com
>
> > -----Original Message-----
> > From: Breukel, C. (HKG) [mailto:C.Breukel@lumc.nl]
> > Sent: Monday, April 24, 2006 5:52 AM
> > To: alt-photo-process-l@usask.ca
> > Subject: Potassium Oxalate developer for Platinum printing
> >
> > (maybe you'll see this message for the second time, I did not see it
> > appear..)
> >
> > 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 Tue Apr 25 08:44:28 2006