water treatments (was Re: Agyrotype)
Whether it is adequate for argyrotype or not is a completely different matter, but leaving water overnight, boiling and Brita filter are insufficient to completely remove chlorine compounds in the water. Chemicals that remove chlorine from water for fish tank react with silver and it just adds another tricky issue. Solid carbon filter does reduce chlorine compounds, but even the top performers made for home use is insifficient to remove it completely. (You will still see cloudiness when dissolving silver nitrate, while you see completely clear solution with deionized water.) Properly treated tap water usually contains 0 or 1 E. coli counts per liter of water. However, if you leave the water out, as the chlorinating compound is slowly lost, the bacterial count goes up. Modern water treatment facility uses multiple methods to kill bacteria (e.g., ozone treatment and chlorination), and this allowed to reduce the amount of chlorinating compounds, compared to decades ago. In case of Boston municipal tap water, there isn't much that can be removed by average home carbon filter. However, negative image of drinking tap water seems pretty persistent and NPR programs occasionally report dining establishments using filtered tap water to save carbon footprint (e.g., a restaurant in San Francisco and the employee cafeteria of google.). I do dinner parties fairly often and I used to comment on this when I describe the menu to the guest, with a pitcher of filtered tap water on the table right next to bottles of fine wine, but these days everyone knows that in my city (where people don't own a TV and listen to NPR). Only thing I miss sometimes is the high hardness of some mineral water. I wish someone sold tablets of calcium and magnesium carbonates, USP grade, to keep in the pitcher to add some hardness. Anyway, if you want clear solution of silver nitrate, use deionized water or triple or double distilled water. How much that cloudiness affects the image quality is a separate question for which I do not have answer. In case of silver gelatin emulsion making, it does make difference. -- Ryuji Suzuki "The truth that I am seeking is in your missing file." (Bob Dylan, Something's Burning Baby, 1985) From: Don Bryant <dsbryant@bellsouth.net> Subject: Agyrotype Date: Tue, 27 May 2008 13:51:45 -0400 > Hi Folks, > > Anyone out there doing Argyrotypes? > > If so how do you deal with the requirement of non-chlorinated water for > processing? This requirement is really putting a damper on my working with > the process. > > Thanks, > > Don Bryant > > >
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