[pure-silver] Re: Adding Pot Bromife to PC-TEA
- From: "Koch, Gerald" <gkoch02@xxxxxxxxxx>
- To: "'pure-silver@xxxxxxxxxxxxx'" <pure-silver@xxxxxxxxxxxxx>
- Date: Mon, 3 Jan 2005 17:00:11 -0500
I am having a bit of fun experimenting at the present time. I'm not shooting
very much film at present and find myself discarding film developer that has
become too old. I was attracted to the idea of a waterless concentrate
developer like HC-110 with a long shelf life. Such a developer was suggested by
Pat Gainer in PhotoTechniques.
I didn't like the negatives produced by his formula. There was a recent post on
APUG where he suggested adding a small amount of potassium bromide. Kodak uses
an addition product of hydrogen bromide and diethanolamine as a source of
bromide ion in HC-110. KBr is slightly soluble in TEA, obviating the need to
find a source of diethanolamine hydrobromide. The ammonium salt seems to be
more soluble in organic solvents. I considered benzotriazole since it is very
soluble in various glycols, but wanted to try bromide first.
A concentrate containing 9 g of ascorbic acid, 0.3 g Dimezone-S and 0.2 g KBr in
100 ml of propylene glycol+TEA diluted 1+49 produces some very nice looking
negatives. Hope to do some printing tonight.
-----Original Message-----
From: pure-silver-bounce@xxxxxxxxxxxxx [mailto:pure-silver-bounce@xxxxxxxxxxxxx]
On Behalf Of Ryuji Suzuki
Sent: Monday, January 03, 2005 4:10 PM
To: pure-silver@xxxxxxxxxxxxx
Subject: [pure-silver] Re: Adding Pot Bromife to PC-TEA
From: "Koch, Gerald" <gkoch02@xxxxxxxxxx>
Subject: [pure-silver] Re: Adding Pot Bromife to PC-TEA
Date: Mon, 3 Jan 2005 15:59:04 -0500
> BTW, data on ammonium bromide seems to indicate that it would be
> easier to dissolve than the potassium salt. I have not tried this out
> as yet.
Ideally, I would start with a carefully formulated developer to avoid all these
issues. What is the aim of dealing with a developer with troubles like this?
I'd not even consider ammonium salt in a fine grain developer. Tertiary amines
like triethanolamine is a way to control the solvent effect of ammonium ion. If
KBr doesn't work, I would look into 6-nitrobenzimidazole or
1-phenyl-5-mercaptotetrazole. The latter is used in quantity like 2-20mg per
liter of working solution anyway.
--
Ryuji Suzuki
"Keep a good head and always carry a light camera."
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