Pyrocat-HD Sudden Death: Any Updates?

chuckroast

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After nearly 4 years of using Pyrocat-HD, I had a batch that suddenly just stopped working.

Part A was about a year old and mixed in Glycol. Part B was around 6 months old. Both were mixed in 500ml quantities and stored in brown glass bottles in a dark storage area.

I'd been using these throughout the year without anything usual going on.

I proved that it was the developer by taking film and letting it sit in the light with this stuff - no color change. Doing the same with a more-recent mix showed color change on the negative, which was then proven using it to develop some film normally.

Do we have any update insights on what causes this and what might be done to avoid it?
 

Andrew O'Neill

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I'm assuming you mixed it from scratch yourself? This hasn't happened to me. I had a batch mixed up in Prop Glycol that sat for almost 2 years. It was stored in a rubberised accordion bottle, with the air squeezed out. It worked fine. When you mixed up a working solution, was there any noticeable colour?
 

Alan9940

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I've had it suddenly die on me 3x over the years. Never came to any conclusion as to what may be the cause. I still use it, but I mix only what I think I'll use in 6 months and toss it after that. For me, it's not worth the risk of trying to get years of service from it
 
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chuckroast

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Yes, mixed from scratch. Part A was mixed in 11/2023.

I had two successive rolls come back with, first, very thin results, and second, none at all. That batch, when mixed had a very minor color change.

The newer batch made in 7/2024 gave me normal results. When mixed, it showed some slight color change, though it seemed not as much as I recall. I will likely just make up a new batch of Part A. I don't think much goes wrong with Part B.

Everything is stored in brown glass bottles. I don't evacuate the air, but they're stored in a dark cabinet. I've used this approach for DK-50, D-76, D-23, Buetlers, PMK ... without any issues, so I think this is some kind of instant failure process unique to Pyrocat-HD.

I think I will limit myself to keep it for 6 months and then mixing fresh.
 
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Alan9940

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chuckroast said:
When mixed, it showed some slight color change, though it seemed not as much as I recall. I will likely just make up a new batch of Part A. I don't think much goes wrong with Part B.
Click to expand...

This is exactly what happened to me all three times that I experienced "sudden death." There was a color change, but experience really wanted my eyes to not believe it! I never had blank film, but I did get very thin negatives that were pretty much worthless.

FWIW, after reading random bits of info out on the interwebs my main suspect causing this issue was the Phenidone. Maybe what I had wasn't fresh enough to last in solution for years? Dunno. I never bought any fresh Phenidone to test that theory as what I have will definitely keep for 6 months which is all I ask of it nowadays.
 
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chuckroast

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Just for clarity - the "color change" to which was referring was the tint that occurs when you Mix Parts A and B together. For the bad developer, there was almost none, for the good it was definitely there, but not as pronounced as I recall. Time to spin up a new batch of Part A.
 

Alan9940

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Yeah, sorry, that's what I was trying to say. I, too, had a color change when A and B were mixed together to make a working solution, but my memory of that change should have clued me in that it should have been stronger.
 
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chuckroast

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I'm referring to regular HD in PG.

I thought the whole point if PG was to reduce oxidative effects?
 
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John Wiegerink

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I now use Pyrocat-HDC instead of the HD or metol version and have, knock on wood, no failure problems. I make it in a fairly large batch, and the last batch is close to 2 1/2 years old. The way Pyrocat developers perform and last was what made me switch to using them. Failure sure seems like an uncommon thing with these developers, but as checkroast points out, it does happen. Any possibility of cross-contamination?
 

Alan Johnson

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Mixing Pyrocat HD - Film Developer

Below are mixing directions for various versions of Pyrocat, including DHD, -M, -P, -MC and -PC.
www.pyrocathd.5x4.co.uk
This version in glycol may eventually fail if the sodium metabisulfite is either not very pure to start with or oxidizes in water absorbed in propylene glycol.
This explanation would only be true if the propylene glycol has been exposed to air for some time, allowing it to pick up some absorbed water from the air.
Edit: The last sentence was rather a goof as the mixture already contains water. But I have had PC-TEA fail if there is some water in it so the oxidation of the metabisulfite remains a possibility.
 
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Andrew O'Neill

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I've been working with 100ml glycol mixed batches of Pyrocat-HD for a few years now, and I prefer it over one litre mixes. Go through it fast, and no chance for sudden death... I'm still planning to mix up some HDC version, and give it a go. I find the idea of subbing two chemicals for one, appealing.
 

lamerko

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I don't make large batches and haven't had any problems, but I think cross contamination of the two concentrates would probably cause problems quickly. I use two syringes for the two concentrates respectively.
 

John Wiegerink

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Alan,
I remember when I first considered trying Pyrocat-HD, after reading all about it here, that IanC made it real clear that the sodium metabisulfite had to be "fresh". Actually, what made me try the HDC version was that I had no fresh sodium metabisulfite on hand when I needed to mix a new batch of HD. I don't know if bad sodium metabisulfite caused chuckroast's sudden death, but I suppose it's possible.
 

John Wiegerink

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lamerko said:
I don't make large batches and haven't had any problems, but I think cross contamination of the two concentrates would probably cause problems quickly. I use two syringes for the two concentrates respectively.
Click to expand...

Yup, I have one permanently marked A and one marked B. A never the two shall meet!
 

lamerko

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Have you tried mixing a new working solution - maybe something went wrong with the previous one?
 

Alan9940

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For the record, I've always stored Pyrocat-HD--either the glycol or distilled water version--in clearly marked amber glass bottles. For measuring, I use separate and marked syringes or graduates, depending on how much working solution I'm mixing. I'm sure I could make a mistake, but I don't believe I've ever cross-contaminated and, yet, I've had "sudden death" with both glycol and water versions.
 

koraks

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Alan9940 said:
amber glass bottles
Click to expand...

Especially for something like pyrocat part B I personally prefer very strongly to use clear glass. It's easier to see the color of the contents that way and changes in color are also far easier to spot. There's no particular reason why pyrocat would have to live in an amber bottle as long as it's kept in a closet/cupboard or otherwise away from strong UV light.
 
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chuckroast

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i pour into a graduated cylinder
 
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chuckroast

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i don't think mine was due to cross contamination
 
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chuckroast

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Does Part B ever go bad?
 

koraks

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chuckroast said:
Does Part B ever go bad?
Click to expand...

I don't see how it could unless you pour a fairly concentrated acid into it.
Maybe it would go bad over the course of several years if you left it in an open beaker. It would absorb a little carbon dioxide from the air, which over a long, long time would neutralize the carbonate.
Realistically: no.
 
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