U of S | Mailing List Archive | alt-photo-process-l | Re: Van Dyck and Kallitype

Re: Van Dyck and Kallitype

Ryuji -- My point was mostly academic, I guess. One of the issues that seems to come up with Fe(III) oxalate is that it contains impurities that may interfere with kallitype/Pt-Pd printing. If the oxalate complex can be made "in situ" from a soluble iron(III) salt and an oxalate salt, reproducibilty might be improved. But again, I'm just hypothesizing.

The complex I use for actinometry has the formula K3 [Fe(C2O4)3] and is prepared from a titrated acid solution of Fe2(SO4)3 and excess K2C2O4. Oxalate is a good ligand for iron(III); I expect that iron(III) oxalate, Fe2(C2O4)3, is probably actually iron(III) ferrioxalate, Fe[Fe(C2O4)3].


Ryuji Suzuki wrote:
If your question is whether you can substitute Fe(III) oxalate with
Fe(III) sulfate and alkali metal oxalate, I think the answer is
positive, although I didn't test kallitype this way. Fe(III) oxalate is
more stable than complex involving sulfate, and water should be the same
as long as the pH is same... (but then you probably thought about it.)

Sulfate is generally not reactive in silver chemistry. (Gelatin gets
affected by it, though.)

But was your point somewhere else?

Jordan Wosnick