I imagine the tripotassium form must have something to do with the method preparation.
This is from a paper on B & S website:
"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 O4) 3) and trihydrogen ferric oxalate (H3 Fe(C2 O4) 3. While both forms are photosensitive, only the acidic form is sufficiently photosensitive to be useful in photography...."
~m
----- Original Message -----
From: Eric Neilsen
To: alt-photo-process-l@sask.usask.ca
Sent: Sunday, January 22, 2006 10:33 PM
Subject: RE: Dissolving Ferric Oxalate Kallitype
No Mike, the book is not for sale. Tri potassium or Tri hydrogen? Ferric oxalate as I know it is Fe2(C2O4)3 . 6H2O. CAS# 19469-07-9
Where is the Potassium or Hydrogen?
Eric
Eric Neilsen Photography
4101 Commerce Street
Suite 9
Dallas, TX 75226
http://ericneilsenphotography.com
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From: Michael Koch-Schulte [mailto:mkochsch@shaw.ca]
Sent: Sunday, January 22, 2006 9:27 PM
To: alt-photo-process-l@sask.usask.ca
Subject: Re: Dissolving Ferric Oxalate Kallitype
Thanks Eric,
I'm thinking maybe I have the tripotassium form of ferric oxalate instead of the trihydrogen form. The tripotassium form apparently requires the addition of oxalic acid (turns it into the trihydrogen form), but the trihydrogen ferric oxalate does not. I'm trying to remember where I read the test for "ferrous" oxalate. Basically, it was similar to the one you outlined but a 5% potassium ferricyanide was dropped onto the paper coated with ferric oxalate sensitiser. No blue dot indicated it was OK. Light blue was sort of OK and green or dark blue indicated not OK. Since my solution still refuses to dissolve I think this test is moot at the moment. No. I've not read Dick Steven book, yet. Why do you have a copy you want to sell me? ;^)
~m
----- Original Message -----
From: Eric Neilsen
To: alt-photo-process-l@sask.usask.ca
Sent: Sunday, January 22, 2006 2:05 PM
Subject: RE: Dissolving Ferric Oxalate Kallitype
Did you add the drop of ferric to a potassium ferricyanide solution? Or the other way around? It should be add the drop of ferric to the cyanide solution. Blue indicates ferrous ions, brown indicates lack there of.
Yes, there is conflicting information. Why? There are many ways to make ferric oxalate and several different proposes for its use. The by products from one method of manufacture may affect one process and may not effect another. Heating can aid in the ferric getting into solution, but it can also convert ferric to ferrous. If your solution has excess or what appears to be excess oxalic acid it can convert the ferrous back to ferric as it cools. Testing should be done with cool room temperature solutions.
Your ferric oxalate should be a clear green to yellow green to yellow brown solution. Age and composition will determine color as does pH. Do you have any 35% or higher concentration H2O2?
Do you have Dick Stevens Book on the Kallitype? He has a rather extensive section on ferric oxalate for use with kallitypes and how it effects color, etc.
Good luck.
Eric Neilsen Photography
4101 Commerce Street
Suite 9
Dallas, TX 75226
http://ericneilsenphotography.com
----------------------------------------------------------------------------
From: Michael Koch-Schulte [mailto:mkochsch@shaw.ca]
Sent: Sunday, January 22, 2006 12:03 PM
To: alt-photo-process-l@sask.usask.ca
Subject: Re: Dissolving Ferric Oxalate Kallitype
There's so much conflicting info on the subject (preparation of Ferric Oxalate) as well. Dick Arentz's book says it's ok to heat to 150 F, but Jeff Mathias paper says no heating should be used. I've tried adding a pinch of EDTA to the bottle to see what happens and it so far has just made the top solution (water) a little more murky after it settles out. Maybe this is good, because the solution use to be almost clear before. I shook the bottle (causing it to revert to it's creamy state momentarily) and dabbed some on a test paper and let it dry. It has the colour of coffee creamer (pinky-beige). Then I applied a drop of 5 per cent of potassium ferricyanide. This turned a deep blue after about 5 minutes. Does this tell me anything? If this was a properly dissolved ferric oxalate solution it would indicate it's bad. But I can't say that it's dissolved properly yet. I'm going to see if the local beekeeping store has oxalic acid in stock. Otherwise I'm going to have order it from my supplier (read: wait a couple of weeks to figure this out).
~m
----- Original Message -----
From: Eric Neilsen
To: alt-photo-process-l@sask.usask.ca
Sent: Saturday, January 21, 2006 10:47 PM
Subject: RE: Dissolving Ferric Oxalate Kallitype
There are different concerns for kallitype than for platinum/palladium. If you were to make up a batch of ferric oxalate from powder, using oxalic acid to get it into solution. You should be able to add small amounts of ferric nitrate to smaller batches as needed to clear it of excess oxalate prior to use. I recall several ferric oxalate conversations; 1994 or 95 than again in 2000. It is a reoccurring theme. I do recall seeing purple crystals in B&S ferric powder over the years when I used it ( not since 1993 or so). I did pick up some ferric nitrate from Dick back in 1993 or 1994 to test the theory of excess oxalate. I don't recall the extend of testing. I did do some kallitypes back then, as well as pt/pd to test the solutions.
I would also ask if they are putting any EDTA in their powder. I ran test about that same time early 90's, and made some rather insoluble white crystal in my ferric oxalate solution with the addition of EDTA tetra sodium. But that was in a clear solution of home brewed, straight to liquid, ferric oxalate.
Eric Neilsen Photography
4101 Commerce Street
Suite 9
Dallas, TX 75226
http://ericneilsenphotography.com
--------------------------------------------------------------------------
From: Michael Koch-Schulte [mailto:mkochsch@shaw.ca]
Sent: Saturday, January 21, 2006 7:46 PM
To: alt-photo-process-l@sask.usask.ca
Subject: Re: Dissolving Ferric Oxalate Kallitype
From what I've read I was lead to believe oxalic acid in the emulsion was an contaminant which had to be treated with ferric nitrate until it was no longer a problem. I'll try the archive. Do you know approximately what date/year this thread went through?
~m
----- Original Message -----
From: Eric Neilsen
To: alt-photo-process-l@sask.usask.ca
Sent: Saturday, January 21, 2006 5:48 PM
Subject: RE: Dissolving Ferric Oxalate Kallitype
Michael, Oxalic Acid will set up the ferric powder to go into solution. I believe that 2g is a very safe place to start. Jeffrey has posted on this, and I think that you'll find that a little excess oxalic acid will help your ferric last longer; not convert to ferrous.
Are you concerned about excessive oxalate running around in your ferric? Or the pH level and its effect on image color?
Eric Neilsen Photography
4101 Commerce Street, Suite 9
Dallas, TX 75226
214-827-8301
http://ericneilsenphotography.com
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From: Loris Medici [mailto:mail@loris.medici.name]
Sent: Saturday, January 21, 2006 3:48 PM
To: alt-photo-process-l@sask.usask.ca
Subject: RE: Dissolving Ferric Oxalate Kallitype
One more point: I presume you used distilled water for making the solution; maybe your distilled water and/or the bottle was contaminated somehow (I always rinse my bottles with copious amnt. of distilled water before using/reusing them). Try to add some drops of silver nitrate soln. to some drops of your distilled water and see if it precipitates or forms a cloudy soln. (Well, even if it stays clear it may not show the water is fine - I don't have that much chemistry knowledge to suggest a better test... But if it gets cloudy, then you'll definitely know that there's a problem with your water!?).
Regards,
Loris.
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From: Michael Koch-Schulte [mailto:mkochsch@shaw.ca]
Sent: 21 Ocak 2006 Cumartesi 21:24
To: alt-photo-process-l@sask.usask.ca
Subject: Re: Dissolving Ferric Oxalate Kallitype
Thanks Eric. Good point. I'll drop Claire a note and see I'm just seeing a neutral sediment or if it really takes that long. No, I did not add any Oxalic Acid, why, what would that do? I noticed the Pt/Pd formulas call for it but I didn't see that mentioned for Kallitype.
~m
----- Original Message -----
From: Eric Neilsen
To: alt-photo-process-l@sask.usask.ca
Sent: Saturday, January 21, 2006 11:09 AM
Subject: RE: Dissolving Ferric Oxalate Kallitype
It may be normal for their FO. Did you ask them? (JPPhotochem)
Did you add any Oxalaic Acid to the powder before mixing?
Eric Neilsen Photography
4101 Commerce Street
Suite 9
Dallas, TX 75226
http://ericneilsenphotography.com
----------------------------------------------------------------------
From: Michael Koch-Schulte [mailto:mkochsch@shaw.ca]
Sent: Saturday, January 21, 2006 10:18 AM
To: alt-photo-process-l@sask.usask.ca
Subject: Re: Dissolving Ferric Oxalate Kallitype
I'm in day two of trying to get ferric oxalate to go into solution. I've made a batch of 50 mls. I've tried microwaving for 20-30 seconds (warm as a cup of coffee, 50 C maybe) and then shaking the bottle for five minutes. I get a milky solution. After about 10 minutes it separates out and I get a nearly clear liquid on top and a chalky sediment on the bottom. I've repeated this at least 15 times in two days. The sediment just isn't budging yet. Is this normal?!
~m
----- Original Message -----
From: Loris Medici
To: alt-photo-process-l@sask.usask.ca
Sent: Saturday, January 21, 2006 6:07 AM
Subject: RE: Dissolving Ferric Oxalate Kallitype
Maybe you can put the bottle in warm (40 - 50C?) water and shake the warm solution. It may help to dissolve the remaining FO. I mixed FO only once (but hadn't the opportunity to use it - I dumped it a year later, without testing... because I've read that it goes bad in 3 months). Mine was dissolved completely after two days just with the initial shaking/stirring - I didn't visited the solution once I mixed it. Two days later there wasn't any precipitate in the bottle. My FO was from B&S.
Regards,
Loris.
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From: Michael Koch-Schulte [mailto:mkochsch@shaw.ca]
Sent: 21 Ocak 2006 Cumartesi 02:40
To: Alt-Photo-Process-L
Subject: Dissolving Ferric Oxalate Kallitype
It's been over 24 hours since I mix my first batch of Ferric Oxalate (20%). I still have about a quarter to half an inch of "sludge" at the bottom of a 100 ml bottle. I've been intermittently shaking the bottle when I get the chance. Should just "stay the course" or is intervention required? Also, how pronouned is the white precipitate when doing the test for presence of Free Oxalic Acid. I'm not sure if I'm seeing just a milkly scum from the undissolved Ferric Oxalate or precipitate. Ferrix Oxalate was obtained from jdphotochem. Thx.
~m
Received on Mon Jan 23 10:28:13 2006
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