RE: Homemade Potassium Oxalate

Thanks Eric I guess I'll order the potassium carbonate and oxalic acid
today.

Don

> -----Original Message-----
> From: Eric Neilsen [mailto:e.neilsen@worldnet.att.net]
> Sent: Friday, March 04, 2005 11:16 AM
> To: alt-photo-process-l@sask.usask.ca
> Subject: RE: Homemade Potassium Oxalate
>
> All right Nick! That is pretty it. Don depending on the quality of the
> ingredients, you may see black specks floating in you finished solution.
> Filter those out before use. If you can find a local chemical supplier (
> thanks to Dan B I have one just a couple miles away) it drastically
> reduces
> the cost of Pot Ox if you brew it yourself. So cheap in fact, that having
> several flavors (warm, cold, + X steps a la dilutions of dichromate)
> around
> is easily done if you have storage space.
>
> Eric Neilsen Photography
> 4101 Commerce Street
> Suite 9
> Dallas, TX 75226
> http://e.neilsen.home.att.net
> http://ericneilsenphotography.com
>
> > -----Original Message-----
> > From: Nick Makris [mailto:nick@mcn.org]
> > Sent: Friday, March 04, 2005 10:05 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 10:24:29 2005