Re: 3 questions (one of them dumb)
From: Judy Seigel <jseigel@panix.com> Subject: 3 questions (one of them dumb) Date: Sun, 16 Nov 2008 23:56:38 -0500 (EST) > A friend, masterminding a class mixing vandyke brown > emulsion, finds that when the silver nitrate is dissolved in > the "distilled water" the solution turns somewhat milky. I > recalled having had the same experience years ago, > ultimately discovering that the "distilled water" was > actually tap water, bottled as and labelled "distilled." That's a very plausible story. > Friend said she'd been told there's a solution that tests > for "distilled" i(I have a note "Solenoid black from NZ" -- > could that be it?) Any info or advice would be gratefully > received. You would want to test for chlorination. Silver nitrate solution is a pretty good test for it. There are some other tests, such as ones used to test chlorination of swimming pools. > So I looked up "chromogenic print" in the > two books I could find (two out of maybe 7 is a good rate > around here). The best definition was in Luis Nadeau's > "Encyclopedia," which explained that most "contemporary > color photographic materials belong to this category" > ... also called "dye coupler prints," and "(improperly) > C-prints." That is right. Dye coupler prints. Color prints made by the RA-4 process or its equivalent are good examples of chromogenic prints. Similarly, color films used today are chromogenic (dye coupler materials). > 3. What is glycin? I know it isn't glycerine, more's the > pity, but it's not in Nadeau... There are of course some > photo chemistry books around here, now deeply buried in the > Morton Street Mississippi Delta. So, I thought, it can't > hurt to ask. http://silvergrain.com/labs/Glycin -- Ryuji Suzuki "Patriotism is the last refuge to which a scoundrel clings." (Bob Dylan, Sweetheart Like You, 1983)
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