Re: white precipitate in VDB
Silver nitrate should be dissolved in deionized or triple distilled or some high grade pure water if precipitation of silver chloride, etc., is to be avoided. In silver gelatin emulsion making, this is essential. (The other extreme would be the silver to be added to "hypo alum toner", in which case it doesn't matter at all.) Bottled water you buy from grocery stores typically have a few counts of bacteria (such as E coli) per liter. Most municipal tap water (at least in Cambridge, Massachusetts, anyway) bacterial count is usually zero per liter. Not that a few counts of E. coli in water is more dangerous than biting your nail, or having a lunch at an office desk, but the question is whether the grocery stores should be selling scientific lab quality water that won't taste good and may contain more bacteria... or something that's purer than tap water but not quite lab quality water. -- Ryuji Suzuki "Make something religious and people don't have to deal with it, they can say it's irrelevant." (Bob Dylan, Biograph booklet, 1985)
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