Pyrocat-HD Sudden Death!

[Alan9940]

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...

[Steven Ruttenberg]

I was thinking same thing, except mix what I need for the developing session and then toss leftovers. It's cheap enough and reshooting some scenes is not possible.

[Willie]

A year and a half - and you are surprised?

Rodinal may last a few decades but nothing else does. Except bad politicians and mean mothers in law.

[Alan9940]

A year and a half - and you are surprised?

Rodinal may last a few decades but nothing else does. Except bad politicians and mean mothers in law.

Well, I've heard tell of folks seeing 2, 3, or more years shelf life. Personally, I've never had it go beyond 1 1/2 years.

[Jim Noel]

My current batch I mixed in 2015. It was still fine yesterday. In the past I have never had "A" go bad,but for some reason, I did have one batch of "B" die suddenly.

[Peter Lewin]

I guess the lesson for those of us who develop more intermittently is to expose a couple of sheets for test developing, before developing anything hard or impossible to replace. I plan on doing this when I return from my California trip before developing the negatives from the trip.

[Steven Ruttenberg]

Amen. I even thought of doing 1 sheet at a time just in case. Rather ruin 1 than 4 or 6 or 10 in one shot.

[Andrew Tymon]

I cut a sheet of film into half inch squares and process it at my standard dilution (it helps if you start this with a new batch so you have a control to measure density against) if it turns black it's still good.

[Pere Casals]

Rodinal may last a few decades but nothing else does.

HC-110, for example, also lasts decades.




I guess the lesson for those of us who develop more intermittently is to expose a couple of sheets for test developing, before developing anything hard or impossible to replace. I plan on doing this when I return...


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.

[swmcl]

Well my Pyrocat-HD is around 8 maybe 10 years old and is still quite OK... My TF4 is a number of years old too.

I do protect them with a squirt of N2 though ...

[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.

[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.

[Pere Casals]

but I don't plan to change my practice just yet.

Well, in the new situation it can be (even more) recommended to throw a drop of developer on a film end to see if developer works, while we prepare the pottery we see if developer is alive. This prevents to ruin nice sheets.

[Flauvius]

Pere:

The critical issue that has been overlooked in this thread is: What quality controls - if any - did the vendor undertake to assure that the liquid Pyrocat, and in whatever configuration your ordered it, was capable at the time it left the vendor to develop film to the standards established by Pyrocat's inventor Sandy King?

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 .

In this regard, I do not believe end users should be expected to pay for the product, and then expend the time to do the testing work of the vendor. As for me, I have switched to powered Pyrocat-HD and as sold by Bostick & Sullivan.

In this regard, I have eliminated at least the possible "liquid" component of the many reported instances, and as documented on this forum, of the "Sudden Death" of Pyrocat when used to develop sheet film. As for the claim that unopened plastic bottles of Pyrocat-MC have a self-life of more than four-five months; in my experience I have found that claim to be untrue.

Flauvius

[Pere Casals]

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.

If concentrate is made in water you cannot dry out the empty volume on top, you will have humidity around water's vapor pressure, 2.34kPa at 20ºC, IIRC, coming from the water's surface.

N2 is very good, butane is even better. Butane is also flamable, of course.

[NPR]

If you can mix your own, I would consider mixing up Pyrocat HDC or PC in glycol, as these need little or no heat and no water to make. All you do (if you can be patient) is put it all in a bottle and turn upside down everyday for a week or so. If you can avoid heat and water, mix in glycol and store in glass bottles they should last 5-10 years.

[Steven Ruttenberg]

If concentrate is made in water you cannot dry out the empty volume on top, you will have humidity around water's vapor pressure, 2.34kPa at 20ºC, IIRC, coming from the water's surface.

N2 is very good, butane is even better. Butane is also flamable, of course.

That is true. It is harder for humidity to form in the presence of N2 though. The N2 would prevent the liquid from evaporating which would allow the formation of O2. I use Argon myself. So long as you ensure positive pressure, ie, gas is flowing out past the bottle opening and then cap it you would be fine.

Nitrogen is preferable as it displaces oxygen and why it is used in almost industries to purge systems of moisture and combustible gazes. Argon is also good at this.

[esearing]

I find this amusing since they ship cachetol in a plastic container with what looks to be electrical tape sealing the lid onto the base container. This is from the technical sheets at PF:

Catechol (pyrocatechin) has a high vapor pressure and it is a phenol. The high vapor pressure means that solid catechol
evaporates readily. When you open a bottle containing solid catechol, you can smell it. Always store the solid catechol in a
tightly capped glass container. When mixing a solution containing catechol, work in a ventilated area. When catechol is in
solution, its high vapor pressure is not a problem.

[jp]

It's probably not practical to ship chemicals in glass containers.

[esearing]

It's probably not practical to ship chemicals in glass containers.

Really? Then how do grocery stores get the isles full of pickles, jelly, milk, salsa, beer, wine, and dozens of other products in glass jars/bottles? Or how would I ever be able to get a glass jar to my house to put my chemistry in? It may not be cost effective compared to plastic, but I doubt it would be that much more for this industry. And it would be more environmentally friendly than me throwing out the contaminated plastic jar.

[jp]

I don't remember the exact rules, but if it's not a safe chemical to spill, and has a hazmat sticker on it, even something electronic with lithium batteries, it has to meet special shipping requirements. It must be able to survive at least a 2m drop at any time in any orientation, be crushproof, pressure change proof, etc... Plastic/metal is much more suitable for this. Jars of food or empty jars are different in that there is not a risk from the spill. And long term food products are probably not flown, reducing regulations.

[Pere Casals]

It's probably not practical to ship chemicals in glass containers.

At least reagent grade chem can be found in both plastic and glass containers.

There are several factors.

First it depends on the compatibility of the chem with glass and with plastics. Sending several big glass bottles in the same packaging it can be risky and extra care/cost should be added, we all know that some chem can be super toxic, extremly corrosive, flamable... and a broken bottle can be a funny party.

Then we have very bad plastic bottles that are penetrated by air, but also we have very good plastics that provide a tight barrier for gasses. In particular, even soda/coke type bottles are very good, because they are designed to not leak CO2 inside, under pressure and for years, some can resist 20 bar while they are flexible, so they can stand drops, accidents, etc.

A large glass container is very fragile, a 100ml one is less a problem. Size matters a lot in the decision.

Of the chem I see, concentrated sulphuric comes in glass, dichromate comes in plastic, Erythrosin B 10grs in glass... I guess this is not by chance, each chem/volume has an optimal container for a certain usage, but IMHO plastic is used a lot because a fall of the container doesn't end in a decontamination protocol.

[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-in-glycol-high-acutance-film-developer-10-liters-Alt-photography/153588384191?hash=item23c294c1bf:g:CYoAAOSwdwpc5DcS

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...

[Pere Casals]

It was amazing, good highlights or acceptable highlights and absolutely no shadows

this is like a huge toe cutter effect... like if chem degradation generated a restrainer, working like a bromide or benzotriazole overdose...

Just for fun, I had been adding some Rodinal to Xtol to generate that kind of "creative" effects.

[Peter Lewin]

Is there a good website with the formula and mixing directions for HDC? Unless I missed it, there is none on Sandy's site. Also, the two "unusual" chemicals are ascorbic acid and glycol. Where do you source those?

[Pere Casals]

Is there a good website with the formula and mixing directions for HDC? Unless I missed it, there is none on Sandy's site. Also, the two "unusual" chemicals are ascorbic acid and glycol. Where do you source those?


https://www.pyrocathd.5x4.co.uk/mixing-pyrocat-hd/

[ParkerSmithPhoto]

Is there a good website with the formula and mixing directions for HDC? Unless I missed it, there is none on Sandy's site. Also, the two "unusual" chemicals are ascorbic acid and glycol. Where do you source those?

Photographer's Formulary (http://stores.photoformulary.com) is where many people get their bulk chemicals.

[Jim Noel]

Photographer's Formulary (http://stores.photoformulary.com) is where many people get their bulk chemicals.

I am not one of those because of poor results with their products on at least 2 occasions . There are at least 2 more reliable sources, one in the West, and one in the East.

[Tin Can]

https://sandykingphotography.com/resources/technical-writing/pyro-staining-developers

[sanking]

Is there a good website with the formula and mixing directions for HDC? Unless I missed it, there is none on Sandy's site. Also, the two "unusual" chemicals are ascorbic acid and glycol. Where do you source those?

Ascorbic acid is Vitamin C, available in pure powder for as little as 3-4$ per pound. Available locally at health food stores, Walmart, etc. Propylene glycol is also a food product, available for about 20$ per gallon, much less for a liter, from Amazon or ebay. Some people use elthylene glycol, the main ingredient in anti-freeze, 8-10$ per gallon at auto supply stores.

Sandy

[Drew Wiley]

There are all kinds of plastics available for chemical storage. Just go to a real lab supply company and check their compatibility charts. These don't outgas at all. But since some of these specialty polymers are very expensive, I just use amber glass bottles for everything.

[NPR]

I get my glycol from the Tractor Supply Store (last time I bought some it was $22 for a gallon) and Trader Joes carries Ascorbic acid in pure power or you can get it at Amazon.

[ParkerSmithPhoto]

Ascorbic acid is Vitamin C, available in pure powder for as little as 3-4$ per pound. Available locally at health food stores, Walmart, etc. Propylene glycol is also a food product, available for about 20$ per gallon, much less for a liter, from Amazon or ebay. Some people use elthylene glycol, the main ingredient in anti-freeze, 8-10$ per gallon at auto supply stores.

Sandy, for your personal work, are you now mixing P-HD or the P-HDC? Do you consider them interchangeable or prefer one over the other? I am just about to mix a new batch and I could go either way.

[ParkerSmithPhoto]

Years ago, I bought a case of these 16oz amber bottles (https://www.usplastic.com/catalog/item.aspx?itemid=34829&catid=448) that hold about 450 mL, and it was a great investment for the darkroom. These wine vacuum stoppers (https://www.amazon.com/Original-Vacu-Vin-Vacuum-Stoppers/dp/B000GA3KCE/ref=sr_1_20_sspa?crid=3PWDFXQ6MJJB5&keywords=vacuum+wine+stoppers&qid=1568075087&s=gateway&sprefix=vacuum+wine+%2Caps%2C138&sr=8-20-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEzRFRLNkNWUlVYNkMwJmVuY3J5cHRlZElkPUEwNjQxNjU3MkgxMEpEQkRaUjJaMyZlbmNyeXB0ZWRBZElkPUEwMTc3NTM5M0ZFTVg5MlNLWkpRUiZ3aWRnZXROYW1lPXNwX210ZiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=) work perfectly with the bottles. I keep all developers in these bottles, and stop and fix in gallon brown glass bottles. NO PLASTIC!

[sanking]

Sandy, for your personal work, are you now mixing P-HD or the P-HDC? Do you consider them interchangeable or prefer one over the other? I am just about to mix a new batch and I could go either way.

I use only Pyrocat-HDC now, and for at least the past five years.

In terms of results -HDC is for all practical purposes perfectly interchangeable with -HD. I spent several weeks running tests to make sure that the amount of ascorbic acid matched closely the results with metabisulfite and bromide that it replaces.

Sandy

[jp]

https://live.staticflickr.com/65535/48708979086_a4a0707677_c.jpg (https://flic.kr/p/2hdffuf)
0909192111_HDR (https://flic.kr/p/2hdffuf) by Jason Philbrook (https://www.flickr.com/photos/13759696@N02/), on Flickr

This is what I use to make HDC part A.

I microwave, stir, microwave the recommended amount of glycol to get it just over 150f, then
go outdoors, and use a paper cup and the digital scales to measure out the pyrocatechol and mix it in,
then use a cold meds cup and digital scale to measure the phenidone and mix it in.
take the ascorbic acid from the fridge, measure, mix the the same way.
Then dispense into small glass bottles (100ml shown) filled with no room for air and only use one bottle at a time till it's gone.

I think the glycol (not premixed with water like some antifreeze products) came from the plumbing section of a big box hardware store. It is tinted blue.
The pyrocatechol and phenidone are from photographers formulary a couple of years ago.
The ascorbic acid is from a food products vendor on ebay or amazon or something.
glass bottles, drug dealer scales are from ebay or amazon sources.

Sometime if I remember, I will get a picture of the oxidized part A. It turns from blue to green eventually as it gets used up and air gets in. Still works fine. Last splash is sometimes gray.

[ParkerSmithPhoto]

I use only Pyrocat-HDC now, and for at least the past five years.

Sandy,

I was about to toss my early 2016 Pyrocat-HD in glycol but decided to run a test roll, thinking that I may have made a dilution error when I experienced "sudden death." My guess was correct. The test roll came out perfectly. I ran part of the same roll through some fresh Pyrocat-HDC in glycol as well. The HDC was a little denser and much browner.

I also ran a test with the old A and the new B which very closely matched the 2016 HD negative, which confirms that my B mix matches the Formulary standard.

One thing I did before making these tests was to create a dilution workflow checklist so that I marked off and confirmed volumes as I added each solution to the water. Sounds silly, but it's so easy to get working and kind of go on auto-pilot, and clearly I made that mistake last week (ruining four rolls), so this should help.

Good news is, this batch of Photo Formulary Pyrocat-HD in glycol has been in brown bottles with vacuum stoppers for coming up on four years, and seems to be working just fine. It was nice to discover that the "sudden death" was really just me making a mistake. I will post some pics of the negatives after they dry.

Thanks again for creating such a fantastic developer.

[sanking]

Good news is, this batch of Photo Formulary Pyrocat-HD in glycol has been in brown bottles with vacuum stoppers for coming up on four years, and seems to be working just fine. It was nice to discover that the "sudden death" was really just me making a mistake. I will post some pics of the negatives after they dry.



Very glad to hear that a second test returned good results. I have made many mistakes myself in mixing formulas, more than I would care to admit. But as they say, to err is human!

Sandy

[ParkerSmithPhoto]

This is what I use to make HDC part A.

JP, what color are your negatives with the Pyrocat-HDC? My original Pyrocat-HD gave slightly warm negatives. The Pyrocat-HDC negatives are distinctly brown, even in the shadows, and have a slightly higher base density.

[jp]

You can see some MF negatives in the background. There seems to be no visible change to base density from the staining. Overexposed like left negative are browner. Normal exposed have a modest sepia/brown proportional stain like the negative on the right. I don't redevelop; used developer goes down the drain before the water stop. If you have too much brown, you may also be overexposing as you gain some film speed with this compared to other popular developers.

[ParkerSmithPhoto]

You can see some MF negatives in the background. That's funny, I didn't even notice those in the photo. :) Actually, the one on the left looks very similar to my FP4 in terms of color and density. I just need to get in the darkroom and start printing these to see how they perform.

[Peter Lewin]

Getting ready to order chemicals to mix HDC from scratch, and wondered about the shelf life of the raw chemicals. Sourcing the minimum quantities of everything but the glycol from Photo Formulary, and picking up the glycol locally gives me enough to make two liters each of A and B. Since one liter will last me over a year at the 1:1:100 dilution, the raw chemicals would need a shelf life of 2-3 years to make this economical vs. the cost of just buying HD pre-mixed in glycol from PF. Any of the components have shorter shelf lives?

[koraks]

It all lasts several years. Don't worry.

[domaz]

I microwave, stir, microwave the recommended amount of glycol to get it just over 150f, then

Microwaving glycol can be a fire hazard, a hot plate stirrer would be far safer.

[Pere Casals]

Microwaving glycol can be a fire hazard, a hot plate stirrer would be far safer.

Gainer himself commented about that long ago "Safe heating with the microwave": https://www.photrio.com/forum/threads/safe-heating-with-the-microwave.35017/

For the record:


If the concern is that the glycol vapor may hit the hot light bulb in the oven and be ignited, let me describe a little experiment. Cut a 1/2 inch wide strip of paper towel or toilet tissue long enough to reach from top to bottom of the perforated grill that covers the bulb and tape an end of it at the top so you can see the direction of airflow through the grill by the angle of the dangle. Put a cup of water in the oven to prevent overloading the magnetron and turn the oven on for a few seconds. You will see that the flow is from the bulb enclosure INTO the oven.

Neither the direction of that flow nor the flashpoint of the liquid being heated will be an issue if no vapor can leave the container of glycol. There are several brands of plastic cling wrap that are microwave safe. It is a simple matter to cover the container of glycol so that vapor does not escape from it, nor is there a chance of a spark entering the container. Leave enough slack in the plastic wrap so that some part of it lies on the glycol surface after it is sealed. You will see that it does not leave the surface until the vapor pressure of the glycol exceeds the atmospheric pressure, which happens at about 370 degrees F where it begins to boil. You can test this with plain water in a pan on a stove top. The plastic wrap will lie on the water surface until the water begins to boil.

There is no need to reach the boiling point of water, much less the boiling point of glycol, and certainly not that of TEA. 150 degrees F (66 degrees C) are more than sufficient to speed up the dissolving of the chemicals in any of the developers that use glycol or TEA as solvent. That is well below the flashpoint of either propylene glycol or TEA. It is a simple matter to test an
individual microwave oven in steps to calibrate it for these solvents. My microwave heats 500 ml of propylene glycol from 70 to 150 degrees F in 1.5 minutes at highest heat.




This was a link I saved long ago, when digging in DR safety.

Glycol (propylen-) boils at 188ºC but it should be heated to say only 66ºC, one has to be bit fool to blow up the entire darkroom with the glycol, but it may happen, a fool's proof procedure is heating water to the boiling point and later throwing the glycol container inside for a while.

If someone that is not able to heat olive oil to 66ºC in the microwave without blowing the kitchen then he should not try to play with glycol in the oven.

[koraks]

I can say from first hand experience that heating glycol and TEA in a microwave can be risky. Those are some nasty burns you get when the stuff boils. Just be careful. I prefer a hot water jacket instead since that experience.

[Pere Casals]

I can say from first hand experience that heating glycol and TEA in a microwave can be risky. Those are some nasty burns you get when the stuff boils. Just be careful. I prefer a hot water jacket instead since that experience.

195879

$5.35 , use that...

You have to heat glycol to 66ºC, check with the IR thermometer each few seconds. If one is able to reach those 188ºC then better to use xtol, because pyro itself is not a candy.

[jp]

Yes, I have the non-contact thermometer like that.
I heat it part way up, stir it, to prevent any sort of hotspot in it, then heat it more to reach the required temp and stir some more. I think the stirring may be more useful than covering with plastic wrap.
I've blown up plenty of food products in the microwave so I know how uneven heating can yield surprises.

[Pere Casals]

Yes, I have the non-contact thermometer like that.
I heat it part way up, stir it, to prevent any sort of hotspot in it, then heat it more to reach the required temp and stir some more. I think the stirring may be more useful than covering with plastic wrap.
I've blown up plenty of food products in the microwave so I know how uneven heating can yield surprises.

Another issue is that with the non-contact thermometer we may be measuring the container surface. Glass is opaque to thermal radiation, we measure the surface, so best would be measuring on the liquid after stirring. This is important if heating small amounts that would increase temp fast, without allowing time for the container wall to have its temp close to the one in the liquid.

[koraks]

Yeah, the thermometer is a good idea.

[Pere Casals]

Yeah, the thermometer is a good idea.

Just a tip, cheap IR thermometers tend to not be very accurate, often we have 1º or 2º errors, so in theory they are not suitable to check developer temp. I guess that this happens because different materials have different IR spectral thermal emission.


... but we may recall what shift our thermometer has in a particular situation, for example we can meter the paper developer temp with a darkroom thermometer and later with the IR one, so we get a "calibration" for that situation, also with glycol, etc. Those non contact thermometers for fever are more accurated because they are specifically calibrated for human skin.

Again, reading should be taken on the liquid, if we point to the container (even is it's clear glass) we get the container surface Temp, which will be relatively close to the liquid inside, but not the same, specially if a fast heating is there.

Anyway this is a very convenient and cheap tool, it is fast and requires no washing after usage, it also tells how enlarger head reheats, etc, etc... just we need to also use an standard thermometer to know the deviation for each situation, when some precision is required.

[jp]

My cheap IR thermometer is mostly used as a laser for entertaining the cat.
Otherwise, it's used in the kitchen and garage for a few things

Indeed it is a few degrees off for certain materials, like human skin. For that work, I measure the forehead/ear/tongue of a normal healthy relaxed person, then the same for the person not feeling well and if the delta is more than a couple of degrees between people I consider them to have some fever symptoms. Things like exercise increase circulation and also affect resulting temp.

After measuring an ill person's temperature, or a food temperature on the stove, or in this case, glycol temperature, one must be willing to entertain the cat subsequently. The beep it makes taking a measurement is known to the cat.

For darkroom work, such as developer temperature, I have a normal analog dial thermometer that I've used since the late 1980's.
If I feel like that needs to be checked, I have a kodak process glass thermometer I can compare it with.

[jp]

My blue glycol part-A starts out a pretty cobalt color, three small bottles of it pictured topped off (no air) and unopened from last month's production of pyrocat HDC.

The right bottle which is half used is starting to get a green tint from oxidation. It can turn fully green if not used and is still OK. Green is basically blue+amber. If it turned black I probably would not use it, but with only 100ml per bottle, the part-A will get used up well before it gets old.

196150

[Jim Noel]

I use a magnetic stirrer with a heating element. This way the solution in question heats evenly with no hot spots. I Made my first one, but the others have been bought for less than $100. My darkroom would be very inefficient without one.