Pyrocat-HD Sudden Death!

[bob carnie]

I watched a photographer who rented my space to process a 2 thousand sheet project and he was using Pyrocat from PF and indeed he had a lot of failures where the shadows completely dropped.. I assumed he was a boob but over the course of the time I was very surprised he was having so much problems and it really did not seem to be any of his workflow methods.. I have ran my share of film and never had these issues with PMK , I do use double developer system .

[Alan9940]

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.

Can't say I've ever seen a glycol version where the metabisulfite is optional, but it could also be the phenidone that's the issue. An early version of Pyrocat-HD called for 2.5g of metol instead of the phenidone. At the time, Sandy suggested that the metol version may be more stable than the phenidone version. I found a notation on digitaltruth suggesting that the shelf life of the phenidone part A is 3-6 months. Interesting. This is based on using distilled water, but that's still significantly shorter than what some users report.

All that said, I mixed a new batch, yesterday, and just developed an 8x10 neg this morning. All good now as it performed exactly as I expected. Therefore, the age of the metabisulfite may be a factor is long-term shelf life, but doesn't appear to affect anything when the batch is fresh. I mixed in distilled water this time and I'll see how it ages. Regardless, I don't plan on keeping it beyond 6 months.

[Pere Casals]

I found a notation on digitaltruth suggesting that the shelf life of the phenidone part A is 3-6 months.

Yes... An smart solution is not mixing the phenidone in the pyrocat concentrate, but you mix the phenidone alone in glycol at 1% or 2% (for convenience) that will keep well, and you throw the right amount directly in the working solution just before usage. Then you have a additional C Part, but this is well worth if one does not know how much the developer batch will last, and it also allows to prepare larger batches.

The same with ascorbic. When Ascorbic is added to control general stain in rotary processing this will decrease the shelf life of part A, but we always can mix it in a separate bottle and adding it later just before usage.

[Steven Ruttenberg]

I would assume the concentrate and or working solution is affected by oxidation, no? I started using Argon to top off my chemicals after I open them each time to prevent any air/o2 from staying in bottle after opening. I think it is best though to mix a batch to cover what you are developing at the time, test it, then develop your batch and discard the rest. If you want to keep, top it off with Argon or Nitrogen before capping the bottle.

[Alan9940]

I would assume the concentrate and or working solution is affected by oxidation, no? I started using Argon to top off my chemicals after I open them each time to prevent any air/o2 from staying in bottle after opening. I think it is best though to mix a batch to cover what you are developing at the time, test it, then develop your batch and discard the rest. If you want to keep, top it off with Argon or Nitrogen before capping the bottle.

I've used Tetenal Protectan for years.

[Pere Casals]

Protectan or butane is better than N2 as butane it is well heavier than air, so it forms a layer on liquid and any remaining O2 is kept far from the liquid surface.

[PRJ]

I've never had Pyrocat die on me using Pyrocat P and PC mixed in Glycol, but I have had issues such as streaking (with both inverted and roller processing) and lower development than I expected, but not by a lot. I've never had blank film. A couple years ago when I was having issues with Pyrocat I did a deep dive back through old negs and prints and came to the conclusion that PMK was a better developer for me. Never had an issue with it and it lasts, so I switched back. I doubt I'll ever use Pyrocat again frankly. Not worth the grief.

For those who have had it die on them, there is a use by date for a reason. And what did Einstein say about insanity?

[Mark Sampson]

For the record, I processed some film this week in Pyrocat-MC (glycol) that I purchased almost a year ago; it worked as expected. Sorry to hear of these problems- but I will buy that developer again, and make sure to use it up before a year has passed. That means lots of photos made, which will be good.

[Steven Ruttenberg]

Protectan or butane is better than N2 as butane it is well heavier than air, so it forms a layer on liquid and any remaining O2 is kept far from the liquid surface.

But the Nitrogen not only displaces the air/O2 it also drys out the empty volume on top. We used it in optic to dry out the "air" in the optical systems before we sealed them up. However, anything heavier than air/O2 and will displace it will work so long as the replacement gas contains zero Oxygen in any form.

[Mark Sampson]

The real answer might be to not let your developer get old. Apparently "fresh is best" in this case.
I'm no one to talk here- I've been able to shoot very little 4x5 this year- but not for lack of desire.
The developer failure reports are a concern, but I don't plan to change my practice just yet.