[pure-silver] storing developer solutions (was Re: Re: HC 110 question ...)

Winemaking stores sell high-barrier Mylar "bags" meant to hold home-made wine. They're the same bags used in the bag-in-a-box "box wines."

I realize that no-one on this list has ever sunk to the depths of drinking the kinds of wines that come in boxes, so I probably should explain in considerable depth exactly what these are...
but what with the pressures of time etc etc, I must defer to another day...also let me make it clear that *I* have had no personal experience with these so-called "wines." Yuk.

These bags work exceptionally well. You can exclude all of the air, and because they are a laminate of high-density polyester and metal foil, their gas permeability is extremely low, much lower than any plastic bottle with the possible exception of rigid PET. I base this statement on what the manufacturers say about the laminate material, and what bottle manufacturers say about PET and HDPE. It's all googleable for the curious.

I store 5-litre quantities of my own Bluefire HR developer concentrate in them between bottling runs. Longevity tests indicate zero loss of activity in nearly two years (same with full, capped rigid PET bottles), versus an insignificant yet measurable loss associated with full, capped HDPE. I use them to store HC-110 stock for months at a time, and have not yet seen any obvious oxygen problems.

They're very inexpensive, something like $4 for a 5-litre bag. They're very easy to wash and re-use.

David Foy

Koch, Gerald wrote: 
Bottles that are soft enough to squeeze may not be the best to use since
they may allow oxygen to diffuse into the contents.  The accordian style
sold in photo stores are particularly bad in this respect.  PET or PETE
bottles while more rigid and not really squeezable are probably a better
choice.

...

quoting someone: Which is why it goes in a bottle you can squeeze the air out 
of to keep
it fresh(er).

...
... 
who quoted someone else: The diluted stock solution has limited keeping 
properties while the
concentrate is eternal.  I forget Kodak's recomendation, 3
months for
partially filled bottles?

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