Making Ferric Oxalate

Kevin Sullivan · Apr 24, 2006

Ole said:
It's a safe bet that any chemical containing trivalent iron ("ferric") is non-stoichiometric. Even something as simple and common as rust varies wildly! Add oxalic acid to that, and you don't have to be a particularly bright scientist to guess that it's going to be diffcult to quantify "purity": The oxalic anion is a very strong chelating agent, and will cling to anything in just about any possible configuration.

Which got me to thinking: Oxalic acid is used as a rust remover in several different applications. Could ferri oxalate solution be made by dissolving rust (or a "purer" FeO(OH)*nH2O in oxalic acid? A small addition of dilute hydrogen peroxide to assore the oxidation state of the iron might be a good idea, but at least it would avoid a whole lot of tricky process steps and explosive chemicals?

Hi Ole,

Interesting idea. It would be fun to make custom FO from famous sources of rust. Scrape some rust off the Brooklyn Bridge or the Eiffel Tower and and then photograph and print those objects with their own Iron. I don't think just adding oxalic acid will do it, might need some other procedure to free up the rust then convert it over, but I'll ask Dr Howard Efner when he comes by, he might have an idea.

thanks for your input,

Kevin

EricNeilsen · Apr 24, 2006

Kevin Sullivan said:
Hi Ole,

Interesting idea. It would be fun to make custom FO from famous sources of rust. Scrape some rust off the Brooklyn Bridge or the Eiffel Tower and and then photograph and print those objects with their own Iron. I don't think just adding oxalic acid will do it, might need some other procedure to free up the rust then convert it over, but I'll ask Dr Howard Efner when he comes by, he might have an idea.

thanks for your input,

Kevin

Kevin, You might also talk to Te Rice or Bob Nugent. They used a formula that started with steel wool.

EricNeilsen · Apr 24, 2006

Should have read, Ted Rice

Kevin Sullivan · Apr 24, 2006

Sorry, thought I was done but this was too tempting...

[/QUOTE]And since you want to talk science, where did you publish the finding about the change in chemistry with the addition of oxalic acid? Was this run through a mass spectrometer? Green, yellow,.

Uhhhm, where to start, Eric. This is basic chemistry. No need to publish it in a fancy journal. And a x-ray mass spectrometer will usually only tell the amounts of pure elements (how much oxygen, iron, hydrogen etc.) not necessarily how those elements are arranged. (FO or oxalic acid, h20, etc.) Also, gas spectrometers don't work because the FO breaks down before it reaches a gaseous state.

I can fax you the chart Dr Howard Efner drew for me that explains it quite well, he seemed to think the whole thing was organic chem 101 level basics. I don't think the chem journals are that interested in this level of redundancy.

Ole even mentions it, in a round about way, here:

Add oxalic acid to that, and you don't have to be a particularly bright scientist to guess that it's going to be diffcult to quantify "purity": The oxalic anion is a very strong chelating agent, and will cling to anything in just about any possible configuration.

Click to expand...

The concept is that the wild tangled arms of the FO can be neutralized with the addition of oxalic acid. The oxalic grabs on to these loose arms and straightens them out, and they can no longer bond to each other as easily. This actually changes the non-stoichiometric FO into a stoichiometric compound, because the FO atoms are bound with oxalic, they can no longer randomly clump together. Now they have a more or less fixed structure. This is why adding oxalic acid to pure FO cause a color shift from muddy yellow brown to the bright emerald green. Its the shift from non-stoichiometric to stoichiometric with the addition of free oxalic acid that causes it to turn translucent green. This is well documented and understood, I'm suprised you aren't familiar with this idea.

This is very easy to test visually if you have some pure FO, just keep adding oxalic acid and watch it turn green. I wouldn't say we are chemically changing the FO to something that is not FO, we are simply controlling its form with oxalic acid.

I think that explains it. There's a little more info in the book The New Platinum Print which also includes Rudiak and DMKs prefered formula. (18g Oxalic Acid to 100ml FO#1, whew, way to much for my taste.)

Cheers,
Kevin Sullivan

Kevin Sullivan · Apr 24, 2006

Quotes all screwed up in above post, but you'll figure it out

Kevin Sullivan · Apr 24, 2006

Howdy,

I see Bob Nugent all the time, I'll ask him.

I suppose you would soak the steel wool in nitric acid to make ferric nitrate, then go through the regular process. I would consider this a cool trick if stuck in a remote locale with no other supplies, but otherwise I would just start with the ferric nitrate directly.

But I think the coolest part would be to use Iron directly off of some historic site as the source of your sensitizer to make prints representing the location. It's more conceptual than anything else.

Could we extract enough iron from human blood to make portraits? Any volunteers?

Kevin

EricNeilsen · Apr 24, 2006

Maybe you could use the steel wool to polish the item_ bridge, tower, car, etc, first in a none visual portion first. Getting a little of the original iron involved.

I do believe it is nitric acid that he uses. It has been since 1992 or 93 that he told me about that either at a Platypus party or at the Platinum Plus gallery.

Eric

EricNeilsen · Apr 24, 2006

Kevin Sullivan said:
Sorry, thought I was done but this was too tempting...

And since you want to talk science, where did you publish the finding about the change in chemistry with the addition of oxalic acid? Was this run through a mass spectrometer? Green, yellow,.

Uhhhm, where to start, Eric. This is basic chemistry. No need to publish it in a fancy journal. And a x-ray mass spectrometer will usually only tell the amounts of pure elements (how much oxygen, iron, hydrogen etc.) not necessarily how those elements are arranged. (FO or oxalic acid, h20, etc.) Also, gas spectrometers don't work because the FO breaks down before it reaches a gaseous state.

I can fax you the chart Dr Howard Efner drew for me that explains it quite well, he seemed to think the whole thing was organic chem 101 level basics. I don't think the chem journals are that interested in this level of redundancy.

Ole even mentions it, in a round about way, here:

The concept is that the wild tangled arms of the FO can be neutralized with the addition of oxalic acid. The oxalic grabs on to these loose arms and straightens them out, and they can no longer bond to each other as easily. This actually changes the non-stoichiometric FO into a stoichiometric compound, because the FO atoms are bound with oxalic, they can no longer randomly clump together. Now they have a more or less fixed structure. This is why adding oxalic acid to pure FO cause a color shift from muddy yellow brown to the bright emerald green. Its the shift from non-stoichiometric to stoichiometric with the addition of free oxalic acid that causes it to turn translucent green. This is well documented and understood, I'm suprised you aren't familiar with this idea.

This is very easy to test visually if you have some pure FO, just keep adding oxalic acid and watch it turn green. I wouldn't say we are chemically changing the FO to something that is not FO, we are simply controlling its form with oxalic acid.

I think that explains it. There's a little more info in the book The New Platinum Print which also includes Rudiak and DMKs prefered formula. (18g Oxalic Acid to 100ml FO#1, whew, way to much for my taste.)

Cheers,
Kevin Sullivan

Kevin, In my basic chemistry courses in college, they didn't discuss ferric oxalate and unfortunately the photography bug was biting at me more than the chemistry bug so I left it before any diuscussion of organic chemistry related to this topic. If the ferric is not changed, that is to a state of not being ferric oxalate anymore, than have those test reveal any loss of speed due to excess oxalic acid? Please send via email or FAX, the chart from Howard. Your use of the term neutralized to me implies that adding more oxalaic acid would slow the speed of that solution. Did you find that to be true?

Not really looking for fancy journals either but if you said it was included in TNPP, that would work : )

I will also readily admit to not having a copy of TNPP but only reviewing it while helping the formulary establish their workshops back in 1999, but I do recall those number from Rudiak and Kennedy only being tested against current (at the time) B&S powder and not against other FO powder on the market.

"Maybe one day some brave PhD student will sort it out, but it's not the path to a shining career", is a quote from one of my emails with Mike Ware on the subject of ferric oxalate.

I shall be happy with mine, but also happy to see your chart from Howard.

Eric

david b · Apr 24, 2006

So eric, will you be a subscriber soon?

Kevin Sullivan · Apr 24, 2006

Your use of the term neutralized to me implies that adding more oxalaic acid would slow the speed of that solution. Did you find that to be true?

Sorry, made sense in English but chemically wrong. The oxalic acid sticks to the arm and prevents it from bonding with other molecules. So in that sense it is neutered, neutralized, restrained, whatever you want to call it. But not neutralized in the acid/alkali PH kind of way. Usually the speed will go up because there are more free floating individuals that don't need to be untangled before they can match up with a metal salt. But this has its limitations, eventually some metal salts will start to fall out of solution spontaneously, especially silver nitrate (hence the classic silver nitrate test for free oxalic acid). And I suppose the solution will be even more acidic, rather than neutral, but I'm not 100% sure.

Rudiak and Kennedy only being tested against current (at the time) B&S powder and not against other FO powder on the market.

Yes indeed. There were no other powdered ferric oxalates available at that time.

KS

Russ Young · Apr 25, 2006

I won't speak for Ted Rice (have known him since 1978) or Bob Nugent (known him since 1980) BUT have watched Bob make ferric oxalate with steel wool- he got the formula from one of Dick Sullivan's priceless issues of LUMEN. Works like a top if you can draw a good vacuum. Makes great ferric oxalate, at least for kallitypes (my application) but no better than B&S version which I've bought since 1984.

Rudiak had a perhaps unique variation on making ferric oxalate which he developed about 1998. It had some interesting ramifications on speed, color and tone. I watched John make it once; he died about ten days later. Did I take notes? Heck no- he'd always be there to ask...
regretfully,
Russ

sanking · Apr 25, 2006

Hi Russ,

Really nice to see one of the original "maestros" on the list. Your article on kallitype in Barnier was the most useful practical working instructions on kallitype I found when I began working the process some years ago.

You should start a thread on soft-focus lenses! There is probably not anyoe in the world who knows more about this subject than you, and this has been an interesting topic here on APUG.

Regards,

Sandy

Russ Young said:
I won't speak for Ted Rice (have known him since 1978) or Bob Nugent (known him since 1980) BUT have watched Bob make ferric oxalate with steel wool- he got the formula from one of Dick Sullivan's priceless issues of LUMEN. Works like a top if you can draw a good vacuum. Makes great ferric oxalate, at least for kallitypes (my application) but no better than B&S version which I've bought since 1984.

Rudiak had a perhaps unique variation on making ferric oxalate which he developed about 1998. It had some interesting ramifications on speed, color and tone. I watched John make it once; he died about ten days later. Did I take notes? Heck no- he'd always be there to ask...
regretfully,
Russ

Making Ferric Oxalate

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