Pyrocat-HD Sudden Death!

[esearing]

I know this has been discussed a bit in other threads, but thought I'd pass on a warning that...YES, Pyrocat-HD can experience sudden death significantly before you expect it and without warning.

I have a 15 month old batch, mixed in glycol, stored in amber glass bottles with a spurt of Protectan after each use, and kept at about 50-55F in the dark. I mix it myself and have done so for more than 10 years. Before that I bought it from PF and had a batch of that go bad in about the same timeframe. No warning. When I mixed A and B together, it turned the appropriate color. I know some of you have had it go bad and others have it last for years. I'm really starting to not trust it due to this Xtol-like sudden death. If I keep using it, I'm going to mix a small batch in distilled water and toss every 6 months or so.

Anyway, just thought I'd pass this along...

I'm curious
a) did you change your developing habits? example - using more dilute and switch to EMA or Semi Stand method, or using a different tank?
b) does your part A foam up when shaken? (This was the early warning sign for me just before death)
c) have you tried warming it to remix the ingredients and/or given it a really good shaking?
d) ruled out the possibility of cross contamination of Part A?
e) where/when did you purchase ingredients?

[bob carnie]

I would advise anyone who does processing that single sheet test with small batch .. followed by a full run of film will give in some cases totally underdeveloped film.. you need to test small volume chemistry with the amount of film you intend to run.
I found this out very early when a assistant did a single roll run , followed by a 8 roll run..

[Alan9940]

I'm curious
a) did you change your developing habits? example - using more dilute and switch to EMA or Semi Stand method, or using a different tank?
b) does your part A foam up when shaken? (This was the early warning sign for me just before death)
c) have you tried warming it to remix the ingredients and/or given it a really good shaking?
d) ruled out the possibility of cross contamination of Part A?
e) where/when did you purchase ingredients?

a) No.
b) Don't know as I've never shaken it.
c) I don't see any particles or anything out of suspension
d) I use separate, marked syringes and graduates for A and B and have always been very careful to avoid cross contamination.
e) I buy all raw chemicals from either PF or ArtCraft and all are stored under what I'd call ideal conditions.

I've been using Pyrocat-HD for many, many years and generally don't have any issues with it other than this "sudden death" thing a couple of times. Unlike what others report--someone in this thread reported their solution being 8-10 years old and still fine--I have never gotten more than 1 1/2 years out of it. And, based on what other Pyrocat users have said throughout this thread, it would seen that many expect on 6-12 months out of it. That's my plan now. Since Pyrocat-HD is my favorite staining formula, I'm going to mix very small batches and plan to use it up within 6 months.

[Doremus Scudder]

...
Something easier, a drop test.

Lights open, let fall a drop of developer on a film end each minute, say 5 drops, then wait (say) 5 min, rinse a bit with tap water and throw the film end in the fixer.

You can compare densities under each drop with those in a test made when developer was fresh, so you not only will know if the developer is alive, you will also know if developer strength has changed and what developing time correction you may apply.

This.

... and, finally, a good use for 35mm film

[Pere Casals]

This.

... and, finally, a good use for 35mm film

Yes !!!

Anyway my best shots are in 35mm, IMHO still I do not deserve a LF camera yet ! It's about learning...

[Tim V]

What ingredients or ingredient would make Pyrocat HD more prone to sudden failure than, say, PMK? I’ve read so many of these threads recently, mostly regarding PF made Pyrocat, but nothing of any other flavour of developer from them. Or am I mistaken?

[Pere Casals]

What ingredients or ingredient would make Pyrocat HD more prone to sudden failure .... ?

The photographer ingredient


If one plans to have a Pyrocat-HD batch in the shelf for a long term then the phototagrapher should make it in Glycol which "is identical to the original Pyrocat-HD formula, but the use of Glycol provides greater shelf life ...... The original version will last up to 1 year, but the version in Glycol has a shelf life of up to 3 years."


For intermitent usage just use glycol.

[koraks]

The photographer ingredient


If one plans to have a Pyrocat-HD batch in the shelf for a long term then the phototagrapher should make it in Glycol which "is identical to the original Pyrocat-HD formula, but the use of Glycol provides greater shelf life ...... The original version will last up to 1 year, but the version in Glycol has a shelf life of up to 3 years."


For intermitent usage just use glycol.

Which is what Alan did, and his stock turned bad within 15 months. Hence the valid question, and the limitation of your textbook response, which evidently does not cover the issue at hand.

To gain more insight, scoot over to Alan's thread on Photrio which has evolved in some doubts about the metabisulfite component, with the following take-aways:
* A potential cause of Pyrocat dying before it should is the metabisulfite, which has already broken down into bisulfite or even sulfite prior to mixing or soon afterwards, offering less protection against oxidation.
* The amount of metabisulfite can safely be increased for more protection and likely without altering the properties of the developer.
* If the prescribed amounts is adhered to, it may be wise to stick to using fresh metabisulfite that has not had time to degrade.

I have some issues with this hypothesis, however. The metabisulfite is IIRC marked as optional in the glycol version, because it should not be necessary in a non-aqueous solution. So the question remains why the developing agent(s) would degrade in this solution that is very low in oxygen throughout its lifetime to begin with. The second issue I have with this hypothesis is that there is apparently no color change, which does not correspond to the mechanism of an oxidized developer. That is to say, it is conceivable that only the phenidone part has oxidized and that its color change is masked by the initial color of the part A concentrate, which tends in my experience to be light red to orange in a home-made glycol part A. In that case, I wonder if using dimezone-S instead of phenidone would be a good idea - which I cannot test, as I only have phenidone.

[Pere Casals]

Which is what Alan did, and his stock turned bad within 15 months. Hence the valid question, and the limitation of your textbook response, which evidently does not cover the issue at hand.

Koraks, you are partially right. Partially it is a textbook response (here you have the full textbook: https://www.digitaltruth.com/articles/stainingdevs.php) and partially it comes from personal experience as I tried 510-Pyro and Hypercat in depth, they have been remaining in the shelf the for last 5 years than 3 weeks ago both were in perfect shape.

I learned in that textbook next concept: "The shelf lives of concentrated stock solutions in either TEA (triethanolamine) or propylene glycol, measure in decades, because they do not oxidize like aqueous solutions do. This fact provides opportunities for unique formulations." ...and the preservative action of metabisulfite is simply not required.

So the question remains why the developing agent(s) would degrade in this solution that is very low in oxygen throughout its lifetime to begin with. The second issue I have with this hypothesis is that there is apparently no color change, which does not correspond to the mechanism of an oxidized developer.

it has to be mentioned that chem bought around may contain a lot of dirt, as purity is expensive the difficult share of buying cheap&good chem is knowing what impurities one may allow for his process. Me, I've not that wisdom, so I mostly use (Merck) reagent grade chem that I can get at good price. In fact profit in the commercial darkroom chem business have been always based in knowing what kind of impurities can be allowed in the ingredients to lower the cost, as pure ingredients are insanely expensive and some impurities can be very harmful even in low concentrations.

You may review several threads here, complaining about pitfalls with pyro chem, several coming from a very well known source.

[Ray Van Nes]

The short answer is yes. I have had this happen several times with different batches. Recently I developed some Efke which worked, although a little thin and then was testing some 5 x12 HP5 within the week and all I got was clear film. So I use PMK for roll film and Rollo-Pyro for sheet film in the Jobo. No failures. When Pyrocat works it is quite wonderful but I do not like playing Russian roulette with my hard earned images.