U of S | Mailing List Archive | alt-photo-process-l | Re: ferric oxalate

Re: ferric oxalate

Thanks so much, Clay. I may try that some time. A few months ago, at my 11th hour panic, I didn't have any-- or enough--oxalic acid on hand (or potassium carbonate?) either, to be able to mix up my own batch of potassium oxalate developer. That's why the sodium acetate developer was such a lifesaver-- all ingredients easily found on the grocery store shelf, on a Sunday afternoon.

But thanks for the recipe. I'll try it some day, when I'm feeling very brave. ;)


On Nov 10, 2008, at 6:21 PM, Clay Harmon wrote:


It is pretty easy to mix up your own potassium oxalate developer from combining oxalic acid, potassium carbonate and water. Here is a cut and pasted recipe from Carl Weese:

2 lbs of Pot Carb with 1.75 lbs oxalic acid to make 1 gallon of water. 1 lbs = 457
g and 1 gallon = 3.8 l ( top of my head but close enough as it is just POT

Mix you Pot Card into cool distilled water; about 1/2 your total volume.
SLOWLY add your Ox Acid as it WILL BUBBLE!!!!. Add to completion and top
off with water to make final volume.

On Nov 10, 2008, at 5:02 PM, Diana Bloomfield wrote:

Thanks, Brian. I'm gonna have to go get that book now.

I almost always use palladium with Na2 for any contrast.

I noticed too-- not much info on the web, but I need to get the second edition of Arentz's book.

Although I was in a panic some months ago, when I was getting ready for a show-- and I ran out of developer right at the 11th hour. I typically use potassium oxalate-- and, naturally, I'm 1,000 miles-- at least-- from anybody who sells it. And my platinum printer friend here was out of town-- so, I did find this little recipe for a sodium acetate developer on the web-- a weird mix of distilled white vinegar and sodium bicarbonate-- all readily available at my local grocery store. I had to go buy this stuff by the gallon/pound-- and felt like a Mr. Wizard mixing up this concoction-- but it worked like a charm. Definitely a cooler (less warm) look in the final print, but it worked fine. And the prints still look good. :)

On Nov 10, 2008, at 5:48 PM, Brian Pawlowski wrote:

Thanks Brian. So that's it-- nothing else added? I was heating the
water, but maybe it should be hotter.
I do like the Chubby Checker idea, though-- I'll try that and-- you
know-- dance like I did last summer.
So, what Pt/Pd process for contrast will you use?

That affects the solution. Na2 process uses Ferric Oxalate in water
as the sensitizer, Na2 contrast agent (smidgen), and Palladium sol'n
(will *not* work with Platinum!).

Wow - I was trying to find a simple web page that describes the
Na2 contrast method for Palladium, but haven't found anything
I can fwd.  The other widely used method is the ratio method,
and there is a pretty good write up here:


This is all well described in Arentz Pt/Pd *Second* Edition...

I'm a little surprised there is not more readily available canned
info on the web that summarizes this... Odd.

Boy, there are other methods than Na2 and ratio methods out there
(Ware's approach, hydorgen peroxide Rudiak mentions, and use
of dichromate in developer for contrast control - all of these
are also covered in Arentz bible...)