Does Pyrocat go bad suddenly?

[waynecrider]

Two test sheets in my Pyrocat stock came out without images. 2 weeks ago my FP4+ was just fine. I nitrogen fill the bottles.

Btw, how long does the "B" solution last. I figure maybe the "A" is the one that goes bad.

 

[Tom Hoskinson]

The Pyrocat "A" solution contains Phenidone, and phenidone does not change color when it goes oxidizes. The Catechol in the "A" solution does change color when it oxidizes. however, when mixed correctly (in uncontaminated water), the "A" solution should have a shelf life of at least 6 months.

The Pyrocat-HD "B" solution when mixed correctly (in uncontaminated water) should have a shelf life greater than 6 months.


Did you mix the Pyrocat yourself "From Scratch?"

You say that you nitrogen filled the bottles, are you sure that you used pure nitrogen?

Did you dissolve the Phenidone in alcohol (this can cause Phenidone oxidation if the alcohol contains water - and alcohols are "water grabbers").

 

[Peter Schrager]

A Bottle

Wayne-I had my first failure of the A bottle several months ago.But this was after maybe 6-8 of sitting around and it had turned noticeably colder in my darkroom.You did not need to lose test sheets as the solution turns colors upon mixing A+B. At least mine always has and that to me is a sure sign that it is time to remake the A solution. One of the reasons I like a homemade developer like Pyrocat-HD. I might add that this was my first time losing the A bottle as I usually use it up first.
best,Peter

 

[waynecrider]

Peter I always thought it was suppose to turn a color when good?

Tom it was mixed from scratch.

 

[Peter Schrager]

Color

Wayne-yes I meant it turns color upon the mixing of the 2 solutions.....to me it means good
Peter

 

[sanking]

The Pyrocat "A" solution contains Phenidone, and phenidone does not change color when it goes oxidizes. The Catechol in the "A" solution does change color when it oxidizes. however, when mixed correctly (in uncontaminated water), the "A" solution should have a shelf life of at least 6 months.

However, even if the phenidone does go bad in the Stock A solution you would still get a fairly strongly image, since In this formula Pyrocatechin by itself is a fairly energetic developer. So even if the phenidone were completely dead you would still not get a clear film. If the pyrocatechin wre also dead Stock A would be dark brown, which I recognize as a useless state.

In my experience there only three scenarios that result in clear film after development, assuming we start with clear Stock A and B solutions.

1. The film was not exposed.

2. In mixing the working solution, two parts of A or two parts of B were mixed with the water, not one part of A and one part of B. This happens more than you would believe, and results in absolutely clear film.

3. The normal order of processing was reversed and the film was fixed before developing.

Sandy

 

[ggriffi]

Sandy,

Are you saying that the ratio of 2:2:100 can have a "failure even if the chemicals are good, or am I misunderstanding?

g

 

[rbarker]

ggriffi - I think he means 2:0:100 or 0:2:100 - that is, pouring from the same bottle twice in error.

 

[ggriffi]

Ralph, thanks, as usual I "misunderstood" :confused:

g

 

[clay]

I'm guessing #2. One time a local photographer 'borrowed' some pyrocat from me. I decanted 100ml of A and B from my 500ml bottles, which were about a month old and half full. He reported back that he got great results the first time, but that a second batch of negatives were completely blank. He cursed pyrocat to high heaven. When I suggested scenario #2 to him, I think he was insulted and just dropped the whole thing and changed the subject. But that is the only reasonable explanation, because I kept using the solution from the exact same batch for another month with no problem at all.

In my experience there only three scenarios that result in clear film after development, assuming we start with clear Stock A and B solutions.

1. The film was not exposed.

2. In mixing the working solution, two parts of A or two parts of B were mixed with the water, not one part of A and one part of B. This happens more than you would believe, and results in absolutely clear film.

3. The normal order of processing was reversed and the film was fixed before developing.

Sandy

 

[sanking]

Yes, that is what I meant. Two part developers like PMK, Pyrocat-HD and Rollo Pyro must have some of both Stock A and Stock B in the working solution, otherwise there will be *zero* developer activity. Stock A contains the reducers and Stock B the accelerators, or activators.

I myself have forgotten one of the chemicals from time to time. If you have any of those pH sticks on hand it would not be a bad idea to test the solution before developing important film. The pH of a working solution of Pyrocat-HD should be around 10.9.

Sandy

ggriffi - I think he means 2:0:100 or 0:2:100 - that is, pouring from the same bottle twice in error.

 

[waynecrider]

I use the Metol version instead of Phenidone in the Pyrocat-HD formula and Sodium carbonate as solution B. Negs were not clear, but a deep shade of brown that you could see thru. Fixed for 4 minutes in TF4, fixer checked ok. Any ideas?

 

[herb]

pyrocad goes bad?

I had the clear sheet phenomena once with doing tray
development of six sheets of 8x10. The first four were
great, the last two clear, in the same mix. It was from
P. formulary.

I use homemade, the a in a 1 liter bottle, B in a 2 liter
bottle, quite an accident, glad to hear about the 0;2;100 episodes.

Herb

 

[sanking]

The use of metol in place of phenidoen or of sodium carbonate in place of potassium carbonate should not per se cause the heavy brown stain you describe.

The heavy brown stain suggests excess oxidation, which could result from the use of old chemicals in mixing the stock solution, or from very long develpment times, especially with rotary processing using small amounts of working solution. In some cases the use of tap water in mixing either the stock or working solutions can degrade the performance of the developer.

Of course, film that has developed a high B+F from age or heat will also develop a heavy stain and it is probably best to develop such film in non-staining developers, especially if you plan to print with UV sensitive processes.

Sandy

I use the Metol version instead of Phenidone in the Pyrocat-HD formula and Sodium carbonate as solution B. Negs were not clear, but a deep shade of brown that you could see thru. Fixed for 4 minutes in TF4, fixer checked ok. Any ideas?

 

[sanking]

I have to assume that the last two sheets did not receive any exposure, or that the solution was somehow contaminated. A Pyrocat-HD working solution in a tray will not suddenely die, unless contaminated. If the working solution is re-used, which I don't generally recommend it will have less energy for the second and third batches of film, and there will be more B+F stain.

Sandy

I had the clear sheet phenomena once with doing tray
development of six sheets of 8x10. The first four were
great, the last two clear, in the same mix. It was from
P. formulary.

I use homemade, the a in a 1 liter bottle, B in a 2 liter
bottle, quite an accident, glad to hear about the 0;2;100 episodes.

Herb

 

[waynecrider]

Of course, film that has developed a high B+F from age or heat will also develop a heavy stain and it is probably best to develop such film in non-staining developers, especially if you plan to print with UV sensitive processes.

Sandy

Hmm, maybe that was it. Anyways, one more try for the heck of it before I ditch the solutions. Any words of advice as to dumping them?