From: "John Black" <jblack@xxxxxxxxx> Subject: [pure-silver] Re: baking soda as wash aid Date: Fri, 18 Feb 2005 17:29:40 -0500 > Bicarbonate freshly put in solution is acid. At what concentration? I am talking about photographically useful concentration for washing aid, like 0.1-0.3M, and also at 20C or 25C. > Bicarbonate only acts as a buffer in the presence of excess CO2. In physiological buffer conditions typically used, yes, but bicarbonate can be used in other ways as well. Regardless of our disagreement in the initial pH point of baking soda solution, it remains unchanged that we need not worry about this change in pH due to storage because it will stay at a value determined by bicarbonate and air, which is 7.x or 8.x and no higher. -- 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.