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
Mix you Pot Card into cool distilled water; about 1/2 your total
SLOWLY add your Ox Acid as it WILL BUBBLE!!!!. Add to completion
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
water, but maybe it should be hotter.
I do like the Chubby Checker idea, though-- I'll try that and--
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...)