Archived posting to the Leica Users Group, 2002/06/24
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Well -the water bath (assuming it's pure) is pH=7.0. Neither acidic (below
7) or alkaline (basic, above 7) When you toss a print in from a developer,
The developer, which is alkaline mixes with it, making it basic .. HOWEVER
not as basic as the original developer, so the process effectively
(although some development may still occur in the highlight areas of the
print, where there is less used up developer. But as Frank and others point
out, that's OK - the concentration change is enough to slow development to a
crawl. Even a 15 second agitated stay is OK - then toss it in the Fixer ,
that's acidic anyway (esp. Ammonium Thiosulfate, the NH4+ ion being the
conjugate acid of a weak base.
Hope that helps!
EC
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> From: owner-leica-users@mejac.palo-alto.ca.us (Leica Users digest)
> Reply-To: leica-users@mejac.palo-alto.ca.us
> Date: Mon, 24 Jun 2002 17:34:40 -0700 (PDT)
> To: leica-users-digest@mejac.palo-alto.ca.us
> Subject: Leica Users digest V22 #324
>
> The purpose of the stop is to provide an acidic environment to stop the
>> development prosess, that requires a alkaline environment....
>> Use of water just takes longer and does not stop as fast the development
>> process.., as it dilutes the developer.... not changing the PH...
>>
>>
>>
>> Frank Filippone
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