Hello!
I would like to thank those members from the list who submitted valuable
advice on handling glacial acetic acid (the concentrated stuff). It really
helped!
I got this 1l glass bottle of it sitting down on floor safely away, and finally
got around to diluting it. I took the advice - to be VERRRRY careful, and it
was really sound advice! I was used dealing with 98% sulphuric or nitric acid
back in school, but this stuff is much more vile. I took one very careful
chemist's sniff at it (NOT from the bottle, of course, just waving my hand over
it to bring the scent to my nostrils), pheeew! I put on my gas mask afterwards.
Had I sniffed in non-chemist way, it would be a really bad experience... I
wouldn't open this indoors!
Anyway, I safely diluted it down to 20% for storage and 5% for stop-bath and
developer-neutralising usage. Still about 2x stronger than ordinary vinegar
(which is about 2% ?). I now have enough stopbath to last me lifetime :)
QUESTIONS:
1) How much dilution should I use for stopping films? Should I lower the pH a
bit? It's currently at around pH 3-4, and I don't want to cause emulsion
swelling by transition from basic to too acidic enviroment (which would casue
reticulation, just like cold emulsion into hot water does). Is this ok? Or
should I raise pH a bit? I do think it's ok, though, just wanted to make sure
at the experts :)
2) for neutralising developer splashed on clothing, hands etc. (to avoid
getting hydroquinone rash or allergy), I think around 2-3% dilution is just
right, whaddya think?
3) HYPO CLEARING - what is the chemical for this? Something with pH lower?
And while it's best useful for baryta (fibre) papers, do you use it with films
too? I find Kodak's own Hypo clear quite expensive at the moment. But I guess
they have more in it than just kitchen soda, right? So what's a hypoclearing
agent for films (all my "hypo" is rapid-fixer formulation based on Ammonium
Thiosulfate) ?
Thanks a lot, you chemically-advantaged friends!
Frantisek
P.S.: I assume it would be more proper to ask this at rec.photo.darkroom or
such, but there I know nobody but here I know you :-)
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