RE: [Norton AntiSpam] RE: Ferric Oxalate or Ferric Ammonium Oxalate

[EJN Photo <ejnphoto@sbcglobal.net>]

Loris, The PT/PD test that showed that fogginess were done back in 1995ish.
I tried it with both potassium based platinum as well as with ammonium based
platinum and sodium and ammonium based palladium. The prints just lacked
punch. I have not gone back and played with just AFO for PT/PD prints since.


There may have been humidity issues as those prints were made in Taos, with
relatively low humidity. They may have been done before I set up a
humidifying chamber/box. At the time, I was more interested in seeing what a
difference the ammonium platinum made than to whether it was time to switch
to AFO.

I do keep some in the darkroom and use it for Chrysotypes. Since I don't
know it as well as FO, I don't want to make any claims about shelf life that
I haven't seen. I thought that Mike has cautioned about letting it go too
long however as it may form solid crystals of an insoluble form.   

EJ & Family
10219 Lynford Dr
Dallas, TX 75238

> -----Original Message-----
> From: Loris Medici [mailto:mail@loris.medici.name]
> Sent: Friday, November 03, 2006 12:10 AM
> To: alt-photo-process-l@usask.ca
> Subject: [Norton AntiSpam] RE: Ferric Oxalate or Ferric
> Ammonium Oxalate
> 
> Hi Eric,
> 
> I haven't done prints with FO other than few Kallitype tests so
> I can't
> share personal experience w/ it as a sensitizer for Pt/Pd salts
> but I'm
> quite sure that my prints don't exhibit any haze and/or
> highlight
> fogging and/or low contrast. Probably yours is a paper/clearing
> and/or
> negative DR problem - my usual coating mix gives me 29 steps in
> the
> 31-step tablet for instance (in other words my usual negative
> DR is log
> 2.9!).
> 
> I'm currently using the same AFO sensitizer that I mixed about
> 10 months
> ago and it still works well without any fogging and/or speed
> change or
> other negative effect. IME AFO is quite stable even when in
> solution -
> you can almost think that it keeps indefinitely "especially
> when
> compared to FO".
> 
> Regards,
> Loris.
> 
> -----Original Message-----
> From: Eric Neilsen [mailto:ejnphoto@sbcglobal.net]
> Sent: 03 Kasım 2006 Cuma 02:27
> To: alt-photo-process-l@usask.ca
> Subject: RE: Ferric Oxalate or Ferric Ammonium Oxalate
> 
> 
> Sandy, Yes the AFO is indeed a much better defined chemical
> than the FO,
> which can vary all over the place. POP pt/pd prints can most
> certainly
> be made. One thing that I seemed to see in prints made from
> negs that
> print well with FO when using AFO, are prints that look a
> little hazy.
> That might be OK, if you were making prints of foggy or moody
> scenes but
> for crisp images, not so hot. It may also be a paper pH issue,
> where
> what works for FO will react differently for AFO prints. It
> does have a
> shelf life after mixing but last at least as long as FO if not
> twice as
> long.