RE: Dissolving Ferric Oxalate Kallitype

Mike, I had a conversation with Bud Wilson at the Formulary. The instructions that are part of the Kallitype and I believe part of their platinum instruction that concern the ferric oxalate were written by the previous owner of the Formulary. He was a chemist and instructor at a university in Montana. In my conversation, Bud could not shed any light on the subject of the tripotassium or trihydrogen and the difference in formula that I have in my books.

Below is from the Formulary instructions of which we speak...

"The photographic term "ferric oxalate" is a misnomer, which has given rise to a considerable amount of confusion in the photographic literature. There are two common forms of this compound; tripotassium ferric oxalate (K3 Fe (C2 04) 3) and trihydrogen ferric oxalate [H3Fe(C204)3]. While both forms are photosensitive, only the acidic form is sufficiently photosensitive to be useful in photography
The original formulas for palladium printing call for dissolving solid ferric oxalate with an excess of oxalic acid. With the original directions, it is not clear which of the two forms of ferric oxalate are to be used. Solid tripotassium ferric oxalate is a trihydrate that is thermally stable up to 110 C and stable in the dark for extended periods of time. The solid can be used in subdued room light; however, the solid is destroyed, turns from green to brown, when exposed to ultraviolet light.

PALLADIUM PRINTING KIT PHOTOGRAPHERS’ PAGE 3
CAT. NO. 07-0007, 07-0009 FORMULARY
Tripotassium ferric oxalate is photoactivated by placing it in an acid solution, where it is converted to the trihydrogen form. Photographers’ Formulary Does Not recommend the use of the green, solid tripotassium ferric oxalate for platinum, palladium, or kallitype printing. Its photoactivity is low and it is difficult to convert to the more active form.
The ferric oxalate supplied with your kit is a 20% solution of trihydrogen ferric oxalate. This chemical is prepared by Photographers Formulary by the iron alum-oxalic acid procedure and contains a slight excess of oxalic acid. This ferric oxalate is ready for use as Sensitizer A without additional mixing. Sensitizer B does require additional mixing; see below.
Trihydrogen ferric oxalate is photosensitive to light in the 460-nm region. As a photosensitive material, ferric oxalate is very slow when compared with silver grain-emulsions. However, ferric oxalate should still be used in a darkroom with red safety light. Trihydrogen ferric oxalate is probably heat-sensitive, but the exact extent is not known. To be on the safe side, do not heat the solution, or the sensitized paper when it is being dried, over 50C/120F. Trihydrogen ferric oxalate is very water-soluble and its solution has a yellow to yellow-green appearance when first taken into room light."

I don't think that you'll get any dispute that ferric oxalate is an "ill defined" substance, but choosing a definition to go by could be tough. A point that came up with Bud, and something that I mention to students, is while it may be ill defined, it does work. And while not every batch will work precisely the same, we are not making life saving drugs only photographic prints. This is why I choose to make my own. With a small investment of about $150 US, and lab ware that I already have, I am able to at my leisure make about 2.5 liters of ferric oxalate in a liquid form. I use the same chemicals time after time and the same procedure. I know what I have with some certainty; Eric's Ferric.

Even the B&S site, which is HTML, does not have the formula written correctly. It also has it as 5 H2O, while my reference books show it as 6 H2O. Way back when, 1994 or so, I pointed out to Richard that perhaps a more accurate statement maybe that if you take 20g of B&S powder and mixed it with 100ml H2O, you would have a 20% solution of B&S Ferric Oxalate Solution, not a 20% Ferric Oxalate Solution. That was not meant to dismiss B&Ss intent of selling ferric oxalate, but rather as a way to account for the ill defined quality of it.

Eric Neilsen Photography
4101 Commerce Street
Suite 9
Dallas, TX 75226
http://e.neilsen.home.att.net
http://ericneilsenphotography.com
 
> -----Original Message-----
> From: Michael Koch-Schulte [mailto:mkochsch@shaw.ca]
> Sent: Monday, January 23, 2006 1:30 PM
> To: alt-photo-process-l@sask.usask.ca
> Subject: Re: Dissolving Ferric Oxalate Kallitype
>
> My bad it was the Photoformulary document I was reading. The problem with
> reading three things at once.
>
> http://www.photoformulary.com/uploads/07-0007.doc
> http://www.bostick-
> sullivan.com/Technical_papers/all_about_ferric_oxalate.htm
>
> ~m
>
>
> ----- Original Message -----
> From: "Eric Neilsen" <e.neilsen@worldnet.att.net>
> To: <alt-photo-process-l@sask.usask.ca>
> Sent: Monday, January 23, 2006 11:29 AM
> Subject: RE: Dissolving Ferric Oxalate Kallitype
>
>
> > Can you post a link? The B&S site, like many, have some dead pages or
> > strange "back door" links. I don't see mention of the ferric issues
> that
> > you raise.
> >
> > Eric Neilsen Photography
> > 4101 Commerce Street
> > Suite 9
> > Dallas, TX 75226
> > http://e.neilsen.home.att.net
> > http://ericneilsenphotography.com
> >
> > > -----Original Message-----
> > > From: Michael Koch-Schulte [mailto:mkochsch@shaw.ca]
> > > Sent: Monday, January 23, 2006 10:28 AM
> > > To: alt-photo-process-l@sask.usask.ca
> > > Subject: Re: Dissolving Ferric Oxalate Kallitype
> > >
> > > This message has been processed by Symantec's AntiVirus Technology.
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Received on Mon Jan 23 15:30:00 2006