Divided FX-2 anyone?

[juan]

Somewhere, I ran across a formula for divided FX-2
Bath A - Metol 2.5g, Glycin 7.5g, Sodium Sulfite 35g. water to 1L,
Bath B - Kodalk 100g, water to 1L

The person who proposed it had never actually used it. I would suppose that with that much sulfite, this would be a developer that partially develops in bath A, as does D23D and Barry Thornton's two-bath.

Has anyone used this developer or have any comments?
Yes, of course, I'm going to give it a try and will report back.
juan

 

[gorbas]

Bath B - Kodalk 100g in 1L of water??? Maybe 10g in 1L? Looks like mistake to me?

 

[juan]

The original formula calls for, IIRC, 35g of Potassium Carbonate. But even Crowley didn't know the exact composition of the carbonate he used. There are threads mentioning that the Kodalk version would be, thus, a safer developer, and Patrick Gainer computed the 35g of Potassium Carbonate to equal just over 112g of Kodalk. From that, I would assume the 100g here is more or less correct.
juan

 

[Gerald C Koch]

The original formula calls for, IIRC, 35g of Potassium Carbonate. But even Crowley didn't know the exact composition of the carbonate he used.

The most common form of potassiun carbonate is the sesquihydrate. Crawley was speaking about being uncertain as to the amount of potassium bicarbonate present in the sesqihydrate (crystalline form). According to Crowley, anhydrous potassium carbonate does not contain any bicarbonate. His developer depended on a small but known amount of bicarbonate being present. He was not saying that the composition of potassium carbonate was unknown. On a previous thread there was some discussion whether the bicarbonate has any proven effect.

The person who proposed it had never actually used it.

Which means that everyone should run out and try it?

The formula most often quoted for FX-2 contains 75 g potassium carbonate for part B not 35 g. Why not just use sodium carbonate instead.

Crawley's formula in the BJP annual also contained 25 ml of 91% isopropanol to ensure that the Glycin dissolved completely.

 

[eSPhotos]

Original FX-2 contains 75g of Potassium Carbonate in solution B.
It is generally diluted 1+1+8 (A+B+water) plus small portion of pinacryptol yellow solution for one shot use.
So you are dipping the film in 10x concentrated solution.
Looking forward to seeing the results.

 

[gorbas]

Interesting! Some 25-30 years ago I used to make 2 bath developer with B bath consisting of 100g of Potassium carbonate, 10g of sulphite and 2g of KBr in 1L of water. B bath was used multiple times. Objective was to get maximum film speed and I was unable to buy Tetenal Emofin so I had to make my own brew. It worked but with little less film speed than Emofin.
So Juan, go for it! Even if you fail it will not be nuclear melt down, just some film burnt and some experience gained. Good luck with experiment!