Just bought large quantities of powder to make PyrocatHD

[Steven Ruttenberg]

I should not run out for a long time!

Question? What is the difference/benefit of using glycol vs water? Is there really any difference in quality of development?

[Jim Noel]

Glycol has far better keeping qualities than water. The P-Cat HD i have mixed in glycol has lasted over 2 years w/o noticeable change in negative quality.

[Steve Sherman]

I mix PyroCat HD in ordinary water, 1000ml at a time, store in a brown jug. I date every chemical in my Darkroom and have not seen any issues with PyroCat kept for 5-6 months.

[mrred]

I should not run out for a long time!

Question? What is the difference/benefit of using glycol vs water? Is there really any difference in quality of development?

When using water, there is much lower chance of contamination from freshly cleaned syringes and other utensils. If you make quantities that are more reasonable for your consumption, you need not worry of it lasting long enough.

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[Jim Fitzgerald]

I've mixed from powders from day one. I've always used water to mix mine. It has lasted over a year in brown liter bottles. I keep it in the dark. I do use a lot for ULF film so I use it up rather quickly if I'm developing a lot of film. So if you mix in water shoot more film!!

[Steven Ruttenberg]

Shooting more film is option! Its crazy how many negatives I have yet to scan, not to mention print in darkroom when I build it next year.

Sounds like a personal preference really.

[Steven Ruttenberg]

I mix PyroCat HD in ordinary water, 1000ml at a time, store in a brown jug. I date every chemical in my Darkroom and have not seen any issues with PyroCat kept for 5-6 months.

I have taken to dating everything and have a boatload of 500ml brown jugs and half as much 1000ml. Mine are glass from PF.

[Mark Sawyer]

Developers age primarily by oxidation. Developers exposed to the air oxidize pretty quick, as air gives up its oxygen easily. Developers not exposed to air but mixed in water age more slowly because the water gives up its oxygen more slowly. Developers mixed in glycol and not exposed to air age slowest because glycol's oxygen is very stable and ain't goin' nowhere. That's why decades-old HC110 in full bottles is still good; it's mixed in glycol.

Keeping developers refrigerated also helps, because cold slows all that stuff down.

[Steven Ruttenberg]

Didn't think of refridgerating the stuff. I csn do that.

[Mark Sawyer]

Didn't think of refridgerating the stuff. I csn do that.

The best method would be to keep the stuff in powder form and mix as needed, within a few weeks of using it.