Archived posting to the Leica Users Group, 2002/03/25

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Subject: RE: [Leica] Darkroom Question
From: Kip Babington <cbabing3@swbell.net>
Date: Mon, 25 Mar 2002 13:40:25 -0600
References: <3C9F3C8F.8000605@istate.net>

At 3/25/2002 07:48 AM -0800, Frank Filippone wrote, in part:

>Bottom line, in understanding the chemistry of the stop bath.....
>Developers work in alkaline environments.  The purpose of the stop is to
>make the environment acidic, such that the developer action is immediately
>stopped.  This gives you a consistent process.

I recall reading, many years ago and probably in a Kodak publication, that 
another purpose of the acid stop bath was to put the film into an acid 
state which would extend the life of the (typically) acid fixing bath.  I 
always thought this sounded logical, but not being a chemist of any sort 
have no way of knowing if it makes any practical sense.  And now that I 
frequently use a supposedly alkaline fixing bath (from Photographer's 
Formulary) I'm not sure what relevance it has for me.  I used an acid stop 
bath for many years, but in the past few have been using just water, and I 
don't think I see any difference in results on film.

Cheers,
Kip

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In reply to: Message from Bill Satterfield <cwsat@istate.net> ([Leica] Darkroom Question)