Pyrocat MC Sudden Death!

I have a question about which of the Pyros (HD or MC) in glycol is more stable over the long term.

I purchased the 500ml kit of Pyrocat MC in glycol from PF with a manufacture date of 105 (October 2006) and used the developer infrequently up to now. Negs looked great. I developed about five rolls during that time and carefully poured each of the solutions into a graduate making sure the lip of the container did not touch the graduate, preventing contamination. Total volume consumed was about 50ml so the air space in the container was minimal and the containers were tightly sealed after each use.

Last weekend I did a roll and and the negs/leader looked suspiciously thin. Knowing I had proper exposure and got poor results, I quickly shot another carefully exposed roll and developed again. The image was all but invisible, only the slightest hint of an image was present and the leader was about Zone V density (I often use the leader density to judge efficacy of a developer). The developer had died in a period of a couple of hours or so!

The color of the raw solution A developer was virtually a coffee brown with a purplish tinge and when diluted with 500ml of distilled water was a moderate to deep purple color.

I called PF and they said the expected longevity of the developer in glycol was easily 4-5 years and that a light coffee color was normal. Mine was more the color of regular coffee.

Since the developer contains ascorbic acid, IIRC, is it subject to sudden death failure as was Xtol?

I ordered another kit (125ml this time) with a manufacture date of 112 (don't know how to translate the code) and the solution A was a much paler color. Also, I noticed on the PF website that this is supposedly a 'new version.' I have not tried the new developer yet.

Anybody know if there were problems early on with MC or what the changes were to create a 'new version?'

Any help would be greatly appreciated,

Fred

Fred,

Are you sure the Formulary was selling Glycol based Pyrocat in 10/06? I thought it was a later date that the Glycol based stuff first became available from the Formulary.

Yup, the label says glycol and the solution was certainly in a glycol base.

Fred

jgjbowen said:

Fred,

Are you sure the Formulary was selling Glycol based Pyrocat in 10/06? I thought it was a later date that the Glycol based stuff first became available from the Formulary.

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The Formulary began marketing Pyrocat-MC and Pyrocat-HD in glycol kits in the summer of 2006. I was there when they made up the first kits and retained them for control purposes. At this point about 600ml of the the original one liter of Pyrocat-MC solution remains, and about 80% of the Pyrocat-HD solution remains. The color of the -MC Stock A was originally light pink and it is now purple/brown. The -HD solution when first mixed was almost colorless, and remains so to this time. Both solutions are still working at full strength, at least they were when I ran the last control development a couple of months ago.

The color of the stock solution of Pyrocat-MC varies quite a bit depending on the mixing temperature, from a very light pink to a somewhat light purple, and it does darken some with age, usually to a darker purple. The color of Pyrocat-HD is nearly always clear, or perhaps a very light amber, and does not darken with age.

I also mixed another liter bottle of Pyrocat-MC myself in the summer of 2006 and used it steadily until spring of this year. At that point there was only about 50 ml of the original solution left and I noticed that at that point it started to turn very dark in color, like dark coffee. The developer was still ok, but seemed to produce more B+F than when new so I discarded it.

I am speculating that the developer picked up some water from the method I use to measure, which is to first pour the stock solution into small glass measuring beakers, and then back into the stock after mixing up the working solutoin. The issue is that sometimes the beakers are not perfectly dry, and during the course of a hundred or more mixings enough water was transfered back to the stock solution and this resulted in some oxidation of the stock.

With regard to the original question my experience is that the -HD and -MC kits in glycol have the same shelf life, but that each may slowly break down if in any way contaminated. So if you pour the stock solution into another container for measuring, make sure this container is perfectly dry and clean, as this may result in minute contamination that will over a long period break down the developer.

Having worked with both Pyrocat-HD, Pyrocat-MC and Pyrocat-PC over the years I would be suspicious of the stock solution if it has taken on a very dark color. This does not necessarily mean that it is bad, but may mean that it is bad.

Sandy King

Sandy,

Thanks for the quick response!

I am confused!

I have been suspending the lip of the original container above the mouth of the graduate and pour in 5ml from each container. I only pour out of the original container, nothing ever gets returned to the container.

Nothing touches the mouth of the original container or enters it nor does it touch the graduate. Water cannot possibly get in the mixing process until the last step.

I was extremely careful to ensure A and B never got together except in the graduate.

Am I doing something improper in the mixing?

I have usually added 5ml A to 5 ml B in the graduate and then pouring that 10ml into 500ml of distilled water for working solution.

Thanks!

Fred

I don't know if it matters, but I have always practiced adding Part A to water from a graduate, and then the next step is to add Part B from a graduate.

My Pyrocat-MC is the large bottle and when I purchased it from the Formulary it first turned yellow after I poured in part B. Then I stir and it turned dark purple. The older the developer gets, the darker the purple. Now it's almost black, but it works like a champ still and the last batch looked as good as the first.

I do use dedicated graduates for pyrocat part A and part B, for the same fright of contamination you mention above.

In your situation I would be confused too, but would likely chalk it up to science fiction, dump it, and buy some more...

- Thomas

Fred Aspen said:

Sandy,

Thanks for the quick response!

I am confused!

I have been suspending the lip of the original container above the mouth of the graduate and pour in 5ml from each container. I only pour out of the original container, nothing ever gets returned to the container.

Nothing touches the mouth of the original container or enters it nor does it touch the graduate. Water cannot possibly get in the mixing process until the last step.

I was extremely careful to ensure A and B never got together except in the graduate.

Am I doing something improper in the mixing?

I have usually added 5ml A to 5 ml B in the graduate and then pouring that 10ml into 500ml of distilled water for working solution.

Thanks!

Fred

Click to expand...

Fred,

Your measuring method seems sound and I don't see anything in the technique you describe that could result in contamination. I am therefore unable to understand or explain the cause of your devloper failure. But I can say for sure that I have 600ml of an original liter of Pyrocat-MC that was mixed at the Formulary in the summer of 2006 and it is still working perfectly, though the color has darkened somewhat compared to the original color.

Also, from my experience Pyrocat stock solutions, whether mixed in water or glycol, do not experience sudden death unless some type of gross contamination takes place. Typically they respond to slight contamination by slowly losing strength over a period of several months.

Sandy King

Fred;
I will leave the technical answer to Sandy King as posted and would agree with all of what he said.
There is however a point in your original post that I must clear up, that being that when you called the Formulary we told you that the developer would last 4-5 years. I am not sure of how that got communicated but our phone staff is well aware of our company policy. That being as follows.
If you are using ANY developer that is over 1 year old that has not been stored in glass or in suitable plastic with no air on it, meaning an absolutely full bottle, you are risking your film. Anything over a year old should be tested prior to developing unreplaceable exposed films.

It sounds like you are very careful and pay attention to your lab practices so as not to contaminate your developers, as you should. And I understand that there are very credible people that can prove longer shelf life than a year on alot of product, our products, Kodak,Ilford, Edwal, Clayton, the list goes on and on, but I must say that stuff happens.

We did PH testing on 3 different sources of distilled water just this morning. The results varied from 5.5 to 7.2. This is commercially available distilled H2O.

I can go on and on about all of the variables that can and will affect the longevity of a developer solution, actually all chemical solutions. That is why at some point you have to draw a line in the sand and say to protect the outcome of all of my efforts to produce a final acceptable image, I must check to see if my solutions are OK before placing my film in them. After a year I believe that the risk goes up expotentially. To many variables.

If you feel that the Formulary misinformed you, I can assure you, that we will step up to the plate and replace the developer, but I can't replace the effort it took for you to get the images.
Please add to your lab practices that if a solution is over a year old that it will be tested prior to applying film to it.

Thanks for your post and thanks to Sandy for the quick answer on his formula.

Bud Wilson
Photographers Formulary
Celebrating our 30th year

Thanks, all, for responding.

I am assuming that I have been bitten by one of the many variables that can get you!

Bud,

I spoke to Sherry first and she transferred me to another woman who basically quoted information that she had gotten from Sandy, that basically the developer is good for 4-5 years, based on empirical data. I took that with a grain of salt and estimated 2-3 years would definitely be pushing it. It lasted 1.5 years and, still, I considered that good except that I was surprised by the rapid deterioration.

I think your advice is right on target: after the developer has passed a year, best be checking efficacy before putting film in it.

I have since purchased the 125ml kit and will cycle those more often, based on my usage. I intend to decant into glass containers as I am not sure how porous the HDPE containers are over the long haul. I ran across a website that reported on the applicability of various plastic containers in our hobby but I can no longer locate it.

(Found it: http://silvergrain.org/Photo-Tech/plastic.html) Looks like HDPE isn't the best for gas permeability. Decant into glass!

My primary purpose for floating this question was to query the knowledgeable sources about the validity of my lab practices and perhaps garner additional information that would extend longevity.

I was hoping Pyro MC would match the longevity of Rodinal, which I have decanted into 125ml glass containers and have had excellent performance over some very long times. But, then, maybe I am just lucky!

Chalk one up to experience!

Thanks again,

Fred

Fred Aspen said:

I spoke to Sherry first and she transferred me to another woman who basically quoted information that she had gotten from Sandy, that basically the developer is good for 4-5 years, based on empirical data. I took that with a grain of salt and estimated 2-3 years would definitely be pushing it. It lasted 1.5 years and, still, I considered that good except that I was surprised by the rapid deterioration.

Fred

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Fred,

I have written here on APUG that Pyrocat mixed in glycol should probably be good for 4-5 years. However, that figure was based on speculation, in part derived from some testing done by Pat Gainer on other developers prepared in glycol that was published in DT some years ago. I do not have empirical data that goes back that far, as the first time I mixed Pyrocat in glycol was in early 2005. This was Pyrocat-HD and the solution is still clear and works as well as when I mixed it. It is stored in a glass bottle that is now about 90% full.

Sandy King

Sandy,

Can I then assume from your comments above that water is the enemy of the concentrated solutions and to avoid contaminating A and B with water?

Thanks!

Fred

Fred Aspen said:

Sandy,

Can I then assume from your comments above that water is the enemy of the concentrated solutions and to avoid contaminating A and B with water?

Thanks!

Fred

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Fred,

That is my assumption. The solutions only become active with the addition of water. In this sense they are like HC-110 stock solution. The stock solution is not capable of any development in the absence of water.

Sandy

For the record, I have been using Pyrocat MC since early 2004 and I have never experienced developer failure. I have always mixed this formula from scratch using distilled water and storing the A & B solutions in brown glass bottles. I do use separate beakers to measure the
A & B solutions to avoid contamination and I use this developer to process everything from 120 roll film to 12x20 sheet film.

Fred Aspen said:

Sandy,

Thanks for the quick response!

I am confused!

I have been suspending the lip of the original container above the mouth of the graduate and pour in 5ml from each container. I only pour out of the original container, nothing ever gets returned to the container.

Nothing touches the mouth of the original container or enters it nor does it touch the graduate. Water cannot possibly get in the mixing process until the last step.

I was extremely careful to ensure A and B never got together except in the graduate.

Am I doing something improper in the mixing?

I have usually added 5ml A to 5 ml B in the graduate and then pouring that 10ml into 500ml of distilled water for working solution.

Thanks!

Fred

Click to expand...

There is one thing wrong with your method of mixing. When you mix A and B before bringing the total volume to 1 liter, you have for a short time a few ml of developing solution that is as much as 100x stronger than your normal working solution. If you were to put a drop of this on a piece of exposed film, it would instantly turn black. This strength also applies to aerial oxidation, so during the short time you take to add the water, the developer chemicals are oxidizing 100 times faster than they should. Instead of lasting the normal 10 or 15 minute developing time, they might only last 0.1 to 0.15 minutes! Please mix the A part with the full amount of water and mix well before adding the B part.

Thanks, Patrick, what you suggest makes perfect sense. I will proceed on your recommendation using the new kit that arrived this week.

Fred

My PyroCat-HD / glycol just failed. I still have 110ml's of both A and B out bottles of 500ml's each. I've never had a problem with the shelf life of PyroCat-HD in the past so am at a bit of a lose. I have another full set of 500ml bottles bought at the same time. I hope they haven't expired as well. I dashed a note off to PF to see what they can share with me. I will keep you posted on what transpires. It's not like I'm a newbie at PyroCat as I have been using it for quite some time. These bottles I have are probably 1 year old. Storage conditions are ideal and I haven't changed my methodology at all.

pyrocat mc

Eric-I lost a batch from the formulary too....I just happen to think at this point it might be the plastic bottles...not really the biggest deal in the world as it was at the end of the bottle and the stuff turns colors when mixed ...so shame on me!!
Best, Peter

Peter, the first batches of Pyrocat HD I made up were stored in small translucent plastic bottles 200ml approx, I found the developer didn't keep that well despite being well sealed. It seemed to go off quickly in partially filled bottles.

The last 2 batches have been stored in 1 litre bottles, the white plastic type used by Ilford for their developers. What a difference, the developer stays fresh even in partially full bottles. I'm not using glycol at the moment, but may in future.

So yes the type of plastic bottle seems to be critical.

Ian

I made up some MC shortly after the formula appeared here and it's still fine. I invested in some Schott glass laboratory bottles with very good quality plastic tops and I wouldn't use anything but glass.

Could there be enough humidity in the air to cause problems while pouring? A darkroom can be a pretty humid place, and I could see enough moisture getting in the bottle from the air to cause problems.

I am certain it is not good practice to mix A and B before adding water. You have there a working solution that is 50 or so times more concentrated than your desired working solution. All of the Pyrocat series of developers begin oxidizing as soon as A and B are together. That is why they are to be used only once. If the developer is too much oxidized after developing a roll of film for, say, 15 minutes to do another roll, how much sooner would the A solution be oxidized by adding the water and carbonate of the B solution before dilution?
Though I am certain, it is worth a test. Add the B solution to the water of dilution, mix it well to get the alkalinity minimized, then add A and test to see if it is still dead.

sudden death Pyrocat

I have had a few issues with sudden death pyrocat from commercial sources.

Ever since then, I mix my own HD, no glycol, use up about 1 liter every six months of concentrate A and B. it does not turn color, and have had no problems. my mixing methods are: add A to water, rinse the graduate into the mixed A, add B to the graduate, add to the mix, rinse more water into the graduate until I get to the desired amount.

Love this developer. Get some really good clouds!

The isoascorbate content of XTOL had nothing to do with its sudden death. It turned out to be a flaw in packaging of the 1 liter kit. That size is no longer made by Kodak, and IIRC the contents of the individual packages have also been redistributed to lessen reactions between the dry contents.

If you make your own Pyrocat MC, you can use either L-ascorbic acid (vitamin type) or D-ascorbic acid, also called isoascorbic, or erythorbic acid.

Tests of my Pyrocat-HD, Pyrocat-P and Pyrocat-MC (in Glycol)

gainer said:

The isoascorbate content of XTOL had nothing to do with its sudden death. It turned out to be a flaw in packaging of the 1 liter kit. That size is no longer made by Kodak, and IIRC the contents of the individual packages have also been redistributed to lessen reactions between the dry contents.

If you make your own Pyrocat MC, you can use either L-ascorbic acid (vitamin type) or D-ascorbic acid, also called isoascorbic, or erythorbic acid.

Click to expand...

I went into my darkroom this afternoon and tested my Pyrocat-HD, Pyrocat-P and Pyrocat-MC (Stock A solutions in Glycol). My B solutiion for all is Potassium Carbonate dissolved in DIW

1. Pyrocat - HD Stock A mixed in Glycol on 5/19/2006. 1+1+100 dilution (in deioniized water) the working solution was transparent and peach colored after addition of the Potassium Carbonate B solutiion. This Pyrocat - HD working solution quickly blackened a 3 inch piece of exposd Efke 35mm KB-25.

2. Pyrocat - P Stock A mixed in Glycol on 3/14/2006. 1+1+100 dilution (in deioniized water) the working solution was transparent and violet colored after addition of the Potassium Carbonate B solutiion. This Pyrocat - P working solution quickly blackened a 3 inch piece of exposed Efke 35mm KB-25 film.

3. Pyrocat - MC Stock A mixed in Glycol on 5/19/2006. 1+1+100 dilution (in deioniized water) the working solution was transparent and yellow/Brown colored after addition of the Potassium Carbonate B solutiion. This Pyrocat - MC working solution quickly blackened a 3 inch piece of exposed Efke 35mm KB-25 film.

I want to say this again. It is my experience that Pyrocat stock solutions, whether mixed in water or glycol, do not experience sudden death in the absence of some type of gross contamination.

Other factors are more complicated. A slight contamination may result in the formula slowly losing strength over a period of several days, weeks or months, depending on the nature of the contamination.

As for the question of container, I personally mix and store all of my Pyrocat solutions in glass containers and recommend this as best practice. It is conceivable that Solution A stored in a plastic container might absorb enough moisture from the air to make it go bad, especially if there is only a small amount of the original solution remaining in the container. However, as I mentioned earlier in this thread, I have control one-liter plastic bottles of both Pyrocat-MC and Pyrocat-HD mixed in plastic containers at the Formulary in the summer of 2006 and the solutions are still good. They are now about 80-90% full as last I recall.

Sandy King