RE: Homemade Potassium Oxalate

Thanks Nick - I have that in my archive already. So were you happy with the
end product?

Thanks,

Don

> -----Original Message-----
> From: Nick Makris [mailto:nick@mcn.org]
> Sent: Friday, March 04, 2005 11:05 AM
> To: alt-photo-process-l@sask.usask.ca
> Subject: Re: Homemade Potassium Oxalate
>
> Don, here is Eric Neilson's note to me of sometime back, along with my
> method which was at least in part derived from Eric's and other methods.
> Same goes for the Cold Bath developer. Can't be absolutely sure that I
> updated the doc the last time out, but one thing I can tell you is that it
> gets quite active for a while, so use extra large containers and make the
> prep outside or in a very well ventilated room with a large sink.
>
> n
>
> Preparation of Potassium Oxalate
>
>
>
> Eric Neilsen wrote:
>
>
>
> I use 2 lbs of Potassium Carbonate (mono) and 1.75 lbs Oxalic Acid. First
> dissolve the potassium carbonate in about 2 1/2 quarts ( 2500ml) of
> water.
> I use distilled or similar quality water to help keep the product as clean
> as possible. Then slowly add the oxalic acid with stirring. It will
> bubble
> quite energetically, as it gives of CO2 and heat. You may consider doing
> this outside, but a good lab should handle it just fine. When you have
> added enough oxalic acid, the bubbling will stop. Top off to make 1 gal.
> I
> usually add an extra 150 gm to the fresh batch to keep it on the acid
> side.
>
>
>
> Nick Makris wrote:
>
>
>
> To make Potassium Oxalate developer for PD/PD prepare as follows:
>
>
>
> Might be better to do this outside or at least with good ventilation as
> the
> process gives off CO2, some heat and a significant amount of bubbles.
>
>
>
> To make 1
> Gallon 2 Qt 1Qt
>
>
>
> Start with distilled water (ml) 2200
> 1100 550
>
> Add grams of Pot. Carbonate mono 907
> 454
> 227
>
> with stirring until dissolved.
>
> Measure Oxalic Acid (gm) 794
> 397 199
>
> Slowly add small amounts of
>
> the above measured Oxalic Acid with stirring,
>
> waiting each time you add until bubbling
>
> stops - continue until all of the above measured
>
> amount has been added - produces balanced ph of 7.0.
>
> Then add more Oxalic Acid to 60
> 30 15
>
> keep solution on the acid side.
>
> Remember, add slowly - produces 5.1 ph.
>
>
>
> Top off with distilled water to make desired quantity.
>
>
>
> On 11/2/01 I prepared a fresh batch of Cold Bath Developer; the old
> developer had a PH of 5.9 and the new batch was 5.0. The discernable
> difference was add contrast - ie, less density in the highlights and more
> density in the shadows and it may have been slower to react???
>
>
>
>
>
> C:\foto\documents\Potassium Oxalate Prep.doc
>
>
>
>
>
> PT/PD Cold Bath Developer
>
>
>
> Nick Makris wrote:
>
> I have run across a formula for PT/PD Cold Bath Developer which is as
> follows:
>
> 175 gm Pot Oxalate, 75 gm Pot mono Phosphate and 1 qt. H2O
>
>
>
> Eric Neilsen wrote:
>
> It has several different formulas but the essence is that about 180g
> Potassium oxalate with 50 to 60 grams Potassium Phosphate mono basic. You
> should be able to dilute the Pot. Ox. solution you have made just short of
> 1:1 with water and add the potassium phosphate mono basic. The Formulary
> also sells the potassium phosphate mono basic. It may give you a bit more
> contrast than the standard PotOx developer. You can dilute your standard
> Pot Ox with water and it will give you a print that is slower, and with
> more
> contrast but it will have more grain or at least that is what I saw with
> those combination of processing elements.
>
>
>
> The potassium oxalate developer that you have made is close to saturation
> (as prepared above). This explains the need to dilute it in order to add
> something else to the solution.
>
>
>
> Therefore, to make a quart of Cold bath developer from prepared/saturated
> Pot. Ox. solution: start with 20oz of the above and add 12oz (60%
> dilution)of distilled water. Slowly add 50-60gm of Potassium Phosphate
> Mono
> basic, continue to stir until completely disolved. If there is any
> undisolved residue, add just a little distilled water, stir and allow to
> stand and repeat if necessary. Adjust this instruction as required.
>
> The use of this may be required in order to render the desired,
> appropriate,
> or required color of the final images. This is the last step after
> determining how much PT vs PD, and the temperature of the developer. The
> PT
> will cool off the PD and the Pot Ox will warm up the PD.
>
>
>
>
Received on Fri Mar 4 10:18:00 2005