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.
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