Pyrocat-HD Sudden Death!

[sanking]

What I find unacceptable is the idea, and without warning, that the product's end user must assume the risk that the Pyrocat as purchased does not meet its claim of fitness for its intended use. Indeed, what is especially unfair in my opinion is that Sandy King's authorized re-seller does not offer a money-back guarantee for Pyrocat, if the product does not perform as advertised .


Flauvius

Hi Flauvius,

I have had a friendly relationship with the folks at PF for a very long time, having taught carbon workshops there off and on since the late 1990s. However, PF is not an authorized re-seller of Pyrocat, in fact no company is that. All of the formulas of the several versions of Pyrocat are available to anyone who may wish to use them, without need of any license fee, and have been available for a long time on many web sites. So anyone is free to mix and sell it, and over the years several individuals and companies have. See for example this ebay seller from Lithuania. https://www.ebay.com/itm/Pyrocat-HD-...oAAOSwdwpc5DcS

I always mix and store Pyrocat in clean glass containers, and encourage others to do so. In glass bottles all of the versions of Pyrocat, even with Solution A mixed in water, should remain stable for at least 6-12 months. If a stock solution stored in glass bottle goes bad within that time frame I strongly suspect some type of contamination of Stock Solution A. Even a minute amount of the alkaline accelerator in Stock B is enough to reduce considerably the expected shelf life of Stock A. Any of the versions of Pyrocat mixed in glycol and stored in glass should be stable for at least two years. At present I have two partially full bottles of Stock A Pyrocat-HDC that are over five years old and both still work fine.

If one purchases the stock solutions in plastic bottles I would encourage you to transfer them to glass bottles as soon as possible. I have absolutely no idea how long the stock solutions last in plastic containers, but almost certainly not as long as they might in glass.

Sandy

[Pere Casals]

how long the stock solutions last in plastic containers, but almost certainly not as long as they might in glass.

Sandy, this should depend on the specific plastic material, not only on the plastic type but also on the manufacturing of the container.

"The barrier effect consists in the formation of vitreous layer, which prevents the release of volatile gases and the movement of oxygen to substrate"


Glass is glass, no doubt. I guess that there are plastic bottles in what Stock Solution A can be as well preserved as with glass, and for sure that there are plastic bottles that will shorten a lot shelf life...


So IMHO it cannot be said how much that chem will be well preserved in a plastic bottle, it depends on the bottle !

[Alan9940]

Any of the versions of Pyrocat mixed in glycol and stored in glass should be stable for at least two years.

Who am I to contradict the father of Pyrocat, but, sorry, that has not been my experience after using Pyrocat-HD for 10+ years. I am meticulous about mixing, storing, and using Pyrocat. The solution is stored in amber glass bottles, in a cool environment, and sprayed with Tetenal Protectan after each opening. I use separate marked graduates and syringes for measure out the solution. Etc...etc. Neither part ever sees even a drop of the other until it's mixed into a working solution. I've experienced "sudden death" 3 times over all the years I've been using it and all times within 12 - 18 months of mixing. I'm still using it, though. I just mixed a new small batch...worked great, btw...that I plan to toss out after 6 months and mix fresh.

[Steven Ruttenberg]

One thing to remember about plastics, is they all out-gas. That out-gassing will contaminate the chemicals. Glass does not out gas. Just be sure to thoroughly clean with91% alcohol/and or acetone (straight acetone, not the stuff you buy in a beauty store) Doing this will insure that all residues are removed. Then as stated above by several, fill the free space with an inert gas, noble gas is preferable, but N2, Argon, etc will work. If it still crashes before it should, then it would have regardless. Best practice is to mix only what you need for each session.

[sanking]

Who am I to contradict the father of Pyrocat, but, sorry, that has not been my experience after using Pyrocat-HD for 10+ years. I am meticulous about mixing, storing, and using Pyrocat. The solution is stored in amber glass bottles, in a cool environment, and sprayed with Tetenal Protectan after each opening. I use separate marked graduates and syringes for measure out the solution. Etc...etc. Neither part ever sees even a drop of the other until it's mixed into a working solution. I've experienced "sudden death" 3 times over all the years I've been using it and all times within 12 - 18 months of mixing. I'm still using it, though. I just mixed a new small batch...worked great, btw...that I plan to toss out after 6 months and mix fresh.

It is always possible that if the volume of Stock Solution A is very low in a bottle there will be slow oxidation from the great amount of air. This is what normally limits shelf life of Pyrocat mixed in water to a 6-12 months.

The method of mixing Pyrocat-HD and Pyrocat-M relies on a small amount of very hot water to get some of the chemicals to go into solution in glycol, so the stock solutions are not entirely anaerobic as they might be if the solution were entirely glycol. As the volume of the stock solution goes down and the exposure to air is greater you could expect some oxidation, which could lead to slow exhaustion of the solution. I guess there is a tipping point where the slow exhaustion becomes sudden death.

Many years ago I began mixing Pyrocat-HDC, which effectively substitutes a small amount of ascorbic acid for metabisulfite and bromide in the formula. The advantage of this formula is that no water is needed to get the catechol, phenidone and ascorbic acid in glycol so the stock solution should always remain anaerobic.

In the old days photographers added glass marbles to their developing solutions to limit exposure of the reducing agents to oxygen. I suspect it would be a good solution for the glycol kits of Pyrocat-HD and -M. Or perhaps just buy the larger kit and divide into smaller bottles.


Sandy

[jp]

Many years ago I began mixing Pyrocat-HDC, which effectively substitutes a small amount of ascorbic acid for metabisulfite and bromide in the formula. The advantage of this formula is that no water is needed to get the catechol, phenidone and ascorbic acid in glycol so the stock solution should always remain anaerobic.

Sandy

Sandy; very thankful for your invention and support!

I have been mixing and using pyrocat HDC in glycol very successfully for a few years of darkroom work after starting with PMK then Pyrocat HD. HDC is very easy to mix and an ingredient simpler. It seems to me like it should totally replace normal pyrocat HD for most uses, yet it has not.

I use a blue glycol antifreeze and it's a pretty cobalt blue when started in 100ml clear glass bottles. As a bottle gets used and air gets in, it turns green and then grey and still works.

[sanking]

Sandy; very thankful for your invention and support!

Hi jp,

Thank you for your kind words.

Much of my work with the use of ascorbic acid in the Pyrocat formula was based on personal exchange of testing with Patrick Gainer, or "Gadget" Gainer as he called himself. Patrick was a former NASA scientists who retired to his native state of West Virginia and developer some highly interesting developer formulas using Vitamin C, including the idea to mix it in an anaerobic solution like glycol. One of his ascorbic acid formulas is mentioned in Steve Anchell's The Darkroom Cookbook, and he published a number of articles in darkroom techniques magazines in the 1990s.

Pyrocat-HDC is the last important variation of the formula that I made, and definitely the best one IMHO. Unfortunately I did not promote it as much as some of the earlier versions and it has not replaced them as it probably should.

Very cool that you are using blue glycol antifreeze!! Cobal blue stock solution A must be a beautiful sight! BTW, the working solution of Pyrocat-P was a lovely lavender color. I believe Pyrocat-P could be mixed in glycol also with ascorbic, but it would probably require some testing as the synergy of p-aminophenol would likely not be the same as that of phenidone.

Sandy

[ParkerSmithPhoto]

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.

Bob, this is exactly what happened to me recently. In fact, it happened overnight!

I was using some PF Pyrocat-HD in glycol that was over three years old BUT it had been stored in brown glass bottles which were always pumped and sealed with the vacuum wine corks. I ran six rolls on Saturday and they were all perfect.

Sunday's four roll tank came out poorly, with slightly thin highlights and almost no shadow detail. (The rolls were from two shoots and were intermixed between developer sessions, meaning that there was no possibility of camera malfunction.)

This was what I found puzzling, as I've always understood that the shadows develop first, then the highlights. Could it be that the Phenidone is really what dies, causing a complete loss of film speed and a loss of super-additivity? I'm not a developer wizard, just basing that on what little I know.

[Raghu Kuvempunagar]

Could it be that the Phenidone is really what dies, causing a complete loss of film speed and a loss of super-additivity? I'm not a developer wizard, just basing that on what little I know.

Pyrocat-HD has two reducing agents - Phenidone and Catechol. Even if Phenidone is fully dead, Catechol should be able to develop the film by itself as it's quite active at the pH of a typical working solution of Pyrocat-HD. It might be possible that Catechol itself was oxidised partially due to the water present in Pyrocat-HD concentrate.

[bob carnie]

Bob, this is exactly what happened to me recently. In fact, it happened overnight!

I was using some PF Pyrocat-HD in glycol that was over three years old BUT it had been stored in brown glass bottles which were always pumped and sealed with the vacuum wine corks. I ran six rolls on Saturday and they were all perfect.

Sunday's four roll tank came out poorly, with slightly thin highlights and almost no shadow detail. (The rolls were from two shoots and were intermixed between developer sessions, meaning that there was no possibility of camera malfunction.)

This was what I found puzzling, as I've always understood that the shadows develop first, then the highlights. Could it be that the Phenidone is really what dies, causing a complete loss of film speed and a loss of super-additivity? I'm not a developer wizard, just basing that on what little I know.

This was a painful experience for me as I have ran thousands of runs of PMK and this dude IMO was very serious and not clumsy whatsoever, but while this was going on he was phoning many experts about the problem. I told him to switch to PMK and be done with it and over a few weeks watched him try every trick in the book, shoot boxes of film to test (while he was in the middle of processing all this film he shot in a remote location) . It was amazing, good highlights or acceptable highlights and absolutely no shadows. I heard many heated discussions with the seller of the product and eveything pointed to operator error and now I am wondering if indeed there was a bad batch during this period...