Ferric or Ferrous Oxalate

[Andrew O'Neill]

Okay all you Kallitype experts out there...Ferric and Ferrous Oxalte are the same thing, correct? I was told by the place I bought it from that they are the same. There is a little voice inside my head saying, "no, it ain't the same".

 

[colrehogan]

No, they aren't the same. The difference is that iron has two oxidation states. Ferric is the higher one (+3), and ferrous is the lower one (+2).

 

[doughowk]

They are not the same. But one of the methods for making ferric oxalate is combining ferrous oxalate & oxalic acid (method described in Dick Stevens book). If you are new to Kallitypes (as I am) you should buy ferric oxalate from a reputable supplier (eg, Bostick & Sullivan, Photographers Formulary, ArtCraft Chemicals).

 

[Andrew O'Neill]

Thanks guys.

 

[Jordan]

I would even say that you should avoid buying ferric oxalate from a place that says that ferric and ferrous are the same thing. They might give you sodium sulfide instead of sodium sulfite on a future order, or something.

 

[Dana Sullivan]

When you expose ferric oxalate to UV light it converts to ferrous oxalate, which in turn bonds to the Pt/Pd salts. I suspect that Pt/Pd prints made with a ferrous oxalate solution would be solid black.

 

[Jordan]

When you expose ferric oxalate to UV light it converts to ferrous oxalate, which in turn bonds to the Pt/Pd salts. I suspect that Pt/Pd prints made with a ferrous oxalate solution would be solid black.

Dana -- I don't think you'd even get as far as making the print. Mixing a solution of ferrous oxalate with Na2PdCl4 or K2PtCl4 (or any of the related salts used in Pt/Pd printing) would probably cause the instantaneous formation of a precipitate of black Pd or Pt powder.