[pure-silver] Re: Arista EDU Ultra
----- Original Message ----- From: "Tim Daneliuk" <tundra@xxxxxxxxxxxxxx> 
To: <pure-silver@xxxxxxxxxxxxx>
Sent: Wednesday, October 22, 2008 11:56 AM
Subject: [pure-silver] Re: Arista EDU Ultra



Mark Blackwell wrote:

Janet how strong was your stop bath???
I had a similar thought when I read this. I *never* use an active stop bath for film. Developers are alkaline, stop baths are acid - that's why they stop the development. It is, however, possible to get 
pinholing when the emulsion moves from the alkali to acid
environments.
I long ago switched to a running water "stop bath" for all film processing. Development does not stop instantly, but that just gets factored into the overall personal ASA/development times I've come up 
with per the usual zone system calibration.
Stop baths and acid fixer do not cause pinholes unless the developer contains sodium carbonate and unless the emulsion is pretty soft. Few modern film developers use carbonate, most use borax, or metaborate neither of which effervesses in acid. Nor does the hydroxide used in Rodinal. I think some of these off-brand films just have emulsion coating problems. Note that both Ilford and Kodak have occasionally had emulsion coating problems although they are quite rare. 

--
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx 
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