Pyrocat HD Question

wfe

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I processed some film today with the same Pyro I used a few weeks ago. It's old but the negs I got a few weeks ago are much better than these recent ones. The recent ones seem flat, very printable but flat. I'm not sure if it is the subject and lighting or the chemistry. I may have been a bit sloppy mixing the A and B amounts today and I'm wondering how critical the amounts and ratios are. Even with my sloppyness the mix can't be off much. I'm also wondering if the negs are a bit underexposed. Does the Pyro go off if it's like a year old? Will old Pyro yield flat negs?

Appreciate any thoughts, recommendations and or ideas. I'm about to shoot a bunch more film and I'm a bit apprehensive about using this batch of Pyro.

Cheers,
Bill
 

Alex Hawley

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Hi Bill - here's my thoughts on your questions:

I'm wondering how critical the amounts and ratios are. Even with my sloppyness the mix can't be off much.
Click to expand...

Its best to err on the side of a little more A than B, but without knowing what dilution rations you are using, and the total quantity you are mixing up, one can't make any assessment of this. If you don't already have one, get a 25 ml graduate cylinder and a medicine dropper. Using those two items, you can get your measuring accuracy down to less than 1/3 ml. I mix up to 2500 of solution and the 25 ml grad serves me just fine.

Does the Pyro go off if it's like a year old? Will old Pyro yield flat negs?
Click to expand...

About a year is all one can expect for shelf life. And yes, the negatives will be flat because the developer has lost a good deal of its reduction capability.
 
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wfe

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Thanks Alex,
I'm mixing 1:1:100 which I have been doing all along with great results. I'm going to ditch the stuff, start with fresh chems and be much more careful with the mixtures.

Cheers,
Bill
 

photomc

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Bill, Alex pretty much covered it all..is your pyrocat mixed with glycol? If so it will last much longer than a year - if in water, then 6 - 12 months has been my experience. Have switched to glycol based pyrocat and must say have been much happier with it. It's a bit like us - it loses energy after it reaches it's prime.
 

Alex Hawley

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Mike has a good point on the variation of shelf life. I haven't done the glycol trick yet. Always mix my stock solution with distilled water. Otherwise, all the variables in tap water could easily shorten both shelf life and overall activity.
 

gainer

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The virtue of the glycol mix, of course, is that it allows little or no ionization until water is added.
 

Alex Hawley

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Ahhhhh. Light bulb clicks on. Pat, I know you have said this before but the thread escapes me; where can I get the glycol, and what type of glycol is it?
 

Bruce Osgood

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jim appleyard

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I've been mixing my HD at 2+2+100 with good success. Perhaps if you tried that?
 

Eric Rose

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you can get the glycol stuff at Photographers Formulary as well. One thing I'm not clear on, you didn't reuse the old batch of chemistry did you? I use to use my dilutiion B, HC110 several times before chucking it, but with Pyro it's one shot only.

I have some solution A and B that was mixed several years ago in a not filled bottle that is still going strong so the shelf life is incredible.
 

Shawn Dougherty

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I've found that any more than 6 months when mixed with distilled water and PCat becomes unpredictable, especially the stain...
 

Jim Noel

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I get my glycol at RV supply stores. It is sold as antifreeze for potable water systems. Also, if you live in a "horse" area, it is sold in gallons at many feed stores. Apparently it has a lot of uses with horses, including preventing water supplies from freezing.
 

TheFlyingCamera

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I've been lucky I guess... I got close to a year out of the first bottle I mixed, and used it all up before it went bad. I'm probably at 9+ months on my next bottle, and that's still going strong.

Another thing to think about is to make sure your lids are as airtight as possible- all developers oxidize, but the pyro-based developers are more prone to exhaustion through oxidation.
 

eddie gunks

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so how do we mix the glycol? instead of water? i could have bought it premixed in glycol but was not sure about what it was and how to use it. how do i use the premix glycol and/or the mix it yourself stuff?

eddie
 

PhotoSmith

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Some people use glass marbles in their developer bottles to displace the air and reduce the oxidation. I haven't tried it, but thought I'd pass it along.

Since pyro developers oxidize so easily, it might be worth a try.
 

Tom Hoskinson

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Mixed in distilled water, the Pyrocat A solution lasts for about 6 months.

The working solution Pyrocat developer was designed by Sandy King to be a one-shot developer.

Mixed in Propylene Glycol instead of distilled water, the Pyrocat A stock solution lasts for years with no deterioration.
 
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