Kirk
My experience is just like yours. PF PC in the original bottles and in one year dead. I now use brown glass bottles, I'm over a year now and all seems good.
Kirk
My experience is just like yours. PF PC in the original bottles and in one year dead. I now use brown glass bottles, I'm over a year now and all seems good.
I had some Pyrocat MC in glycol from the Formulary that went bad in perhaps one year. In fact, it sat unopened in the original bottles for that time. I think that supports Ian's theory.
__Originally Posted by Kirk Gittings
Perhaps...
As per Ian's comment... 'Low grade plastic bottles (definitely) allow oxygen to diffuse through the wall into the solution'.
Thus, my suggestion to you yesterday... That Amber/Brown Glass Bottles are always best!
--
Best regards,
-Tim.
_________
I believe Ian has identified the problem. There is in fact a small amount of water in the Pyrocat in Glycol solutions sold by the Formulary as it is needed to get the bromide and metabisulfite in solution at a fairly low mixing temperature. But if oxygen diffuses through the wall of the plastic it can cause Solution A to go off. I always mix developers in glass, never plastic. If you buy any version of Pyrocat in plastic containers I recommend that you transfer it to glass as soon as possible.
At this time I mix a slightly different version for my own work that avoids any water at all, Pyrocat-HDC. In the HDC formula bromide and metabisulfite are replaced by ascorbic acid. Results with -HDC are virtually identical to the original Pyrocat-HD formula.
Pyrocat-HDC (Solution A mixed in glycol)
Stock A
Propylene Glycol at 150F 750ml
Pyrocatechin 50 g
Phenidone 2.5g
Ascorbic Acid 4.0g
Propylene Glycol to 1000ml
See http://www.pyrocat-hd.com/html/mixing.html for other mixing information.
Sandy
For discussion and information about carbon transfer please visit the carbon group at groups.io
[url]https://groups.io/g/carbon
Sandy; could HDC be made with water instead of propylene glycol to save an ingredient and a couple bucks? I don't need it to last forever.
Yes, you could mix -HDC in water. I just have no idea how long it would last. To save money you could actually mix -HDC in ethylene glycol (aka anti-freeze) rather than propylene glycol.
Sandy
For discussion and information about carbon transfer please visit the carbon group at groups.io
[url]https://groups.io/g/carbon
I store my Pyrocat in glass bottles. If the bottles are kept in a dark place, i.e. refrigerator, darkroom, etc clear is fine.
Glass bottles....sounds like a plan.
Thanks,
Kirk
at age 73:
"The woods are lovely, dark and deep,
But I have promises to keep,
And miles to go before I sleep,
And miles to go before I sleep"
Based upon my following experience in storing and using the PF's Pyrocat-MC, plastic bottles are not likely to be the problem. Allow my to explain:
I have developed developed Tri-X 320 over many years by use of the semi-stand method, and in a can. I have consistently used the 1:1:100 ratio that Sandy recommends, and my staring temperature is 71 degrees Fahrenheit as determined by a Kodak No. 2 thermometer. My Ambient temperatures range from 66-71 degrees Fahrenheit.
Shortly before X-Mas of 2011, I received a liter of Pyrocat-MC in a plastic bottle from the Formulary. As is my practice, on December 28, 2011 I decanted the Pyrocat into two 500mm Boston Amber glass bottles. in turn, I sealed the bottle tops with several layers of Surran wrap, and then taped the Surrran wrap to the bottles.
On January 11, 2013, I did the same thing with another shipment of Pyrocat-MC from the Formulary. Once open, I do not use marbles to displace oxygen from my bottles of either Parts A or B.
I have used Pyrocat-MC for several years and am I well aware of its "Sudden Death" characteristics/. Long ago discussed this issue with Sherry of the Formulary. Although Sherry has suggested "that a litte' amber is ok, my experience has been that even "clearish" Pyrocat that I have stored for a year can be dead, and without being subject to any possibility contamination.
As such, this afternoon I opened a "fresh" bottle of Pyrocat that I had stored since December 28, 2011 to develope a few negatives. Is was like Vermont syrup, dark amber. So, 500mm of Pyrocat MC went down the drain. Then I opened a bottle from my January 11, 2013 shipment. Wile it was not as "dark" as the bottle from December 28, 2011, it too was distinctly "brownish". So, another 500 mm of Pyrocat MC went down the drain. However, not to be denied I opened a bottle of the Pyrocat-MC that I received from the Formulary on December 16, 2014. Although it was slightly "yellowish", it performed as I expected.
Accordingly, based upon my years of using Pyrocat-MC, I have concluded:
1. Don't stock-up on Pyrocat-MC part A, it "goes bad" after 6 months.
2. If Part A is anything other than "slightly amber/brownish", it is likely to be bad.
3. Once the 500mm glass bottle is half empty, throw the remain down the drain. Since I use a syringe with a length of polypropylene to extract Part A, I suspect that with each extraction oxygen is introduced into the bottle and, which, starts to oxidize Part A. Indeed, I have had bottles that were half full, were only faintly "brownish", but produced nearly no development.
4. Part B does not change color and does not seem to subject to oxidation. In short, Part B does not seem to "go bad". Indeed, I have used Part B that was six years old with "fresh" Part A and the negatives developed nicely.
My only suggestion to forego Pyrocat-MC's sudden death problem is that Sandy introduce a true color indicator into Pyrocat-MC, but which does not impact upon the developer's ability to produce negatives of the type processed in fresh Pyrocat.
Kirk:
As for bottles for use with Pyrocat, I would suggest that you only use new bottles to avoid the possibility of residue contamination.
Flauvius
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