Uneven development - Pyroact HD with JOBO 1520 & 120 film

[Jay DeFehr]

On Sandy's advice, I added a few grams of Sodium Sulfite per liter, to the developer itself, and that removes the color entirely. However, it also lessens the staining properties of the developer if I understand correctly. The developer still tans, but it stains less, according to how much Sodium Sulfite you add.

Ken,

What you're describing is the Color Coefficient and the effect on it by the addition of sulfite to a staining developer. More sulfite = less stain until, at some concentration of sulfite there is no more stain. Ascorbic acid affects the CC in almost exactly the same way as sulfite, and when used together their effects are cumulative. To optimize a developer, sulfite, ascorbic acid, or some combination of the two are added incrementally until the level of general stain is eliminated or acceptably decreased. This is the minimum concentration of stain controlling agents, and it will vary somewhat with film and with contrast. Fresh film should always be used for testing. After the minimum concentration is found, an upper limit should be found, beyond which stain formation is unacceptably decreased. Between these two points lies a range within which other factors can be considered. With Hypercat, I used close to the minimum concentration of ascorbic acid to maximize stain, while minimizing any development contribution by the ascorbic acid. With 510-Pyro I used close to the maximum concentration of ascorbic acid to maximize development potential, and resistance to aerial oxidation for rotary and tray processing. It is also true that catechol is far more sensitive to the effects of sulfite and ascorbic acid than pyro is, which favors the choices I made for the kinds of developers I intended to make.

I use Ron Mowerey's Superfix, an extra-rapid, neutral fix, which fixes TMY in one minute, and leaves no trace of magenta after the wash. I'll never go back to standard rapid fixers.

[Ken Lee]

I use Ron Mowerey's Superfix, an extra-rapid, neutral fix, which fixes TMY in one minute, and leaves no trace of magenta after the wash. I'll never go back to standard rapid fixers.

Thanks for the explanation. I bow before all Chemists and Physicists !

Is there a formula for Ron Mowerey's Superfix - or is it a proprietary product ?

If it's proprietary, where is it available ?

[eman]

Yes perhaps that is it Sandy. I use Kodak Rapid fix. I recall reading somewhere that, at least with Edwal hypo test, that it doesn't work properly at film strength dilutions.
Fixer that should be 'bad' tests OK, so I mark off the rolls/sheets. Obviously your system works in any case!

Matus, I would definitely use hypo clear for both film and prints. Film is treated just a couple minutes then you can use running wash or exchanges of still water for 5 mins., your choice. It doesn't hurt anything afaik, to go longer in hypo clear than the recommended time, but I'll defer to Sandy as to whether it will affect the stain of pyrocat negs. Use HCA once and toss it. Once at working strength it only lasts 24 hours, or when it's capacity is reached.

With PMK pyro, it was recommended NOT to use hypo clear...or at least the mention of HCA was omitted in my read of the 1st edition book, and a long wash time of 20mins - 1/2 an hour was the recommendation. That extended wash time was also considered to increase staining, which, like the after-fix bath of used developer, may or may not be the 2nd edition's recommended procedure.

[Jay DeFehr]

Thanks for the explanation. I bow before all Chemists and Physicists !

Is there a formula for Ron Mowerey's Superfix - or is it a proprietary product ?

If it's proprietary, where is it available ?

Superfix

DH2O 500ml
sodium sulfite 10g
ammonium thiocyanate 10g
thiourea 10g
ammonium thiosulfate, 60% 200ml
(acetic acid 28% 3 parts, water 8 parts) as needed to adjust pH to 7
DH2O to 1 liter

There are variants using sodium metabisulfite and/or boric acid to adjust the pH, and even to acidify the fix, which I do when using my superfine grain developer.

[Ken Lee]

Superfix

DH2O 500ml
sodium sulfite 10g
ammonium thiocyanate 10g
thiourea 10g
ammonium thiosulfate, 60% 200ml
(acetic acid 28% 3 parts, water 8 parts) as needed to adjust pH to 7
DH2O to 1 liter

There are variants using sodium metabisulfite and/or boric acid to adjust the pH, and even to acidify the fix, which I do when using my superfine grain developer.

Thanks !

Is there an affordable way to test pH ? I recall pH paper from student days, but perhaps there is something newer.

[Jay DeFehr]

Ken,

The pH test strips are good enough for this application, but not for precise work. pH 7 +/- is typical for swimming pools and spas, so the same methods for testing those systems will also work for testing neutral fixers. Besides, the exact pH of these fixers is not really critical, so measuring pH is optional, in my opinion. A good pH meter is a luxury, and priced accordingly.