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." ================================================================================ ============================= To unsubscribe from this list, go to www.freelists.org and logon to your account (the same e-mail address and password you set-up when you subscribed,) and unsubscribe from there. ============================================================================================================= To unsubscribe from this list, go to www.freelists.org and logon to your account (the same e-mail address and password you set-up when you subscribed,) and unsubscribe from there.