Archived posting to the Leica Users Group, 1998/11/03

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Subject: [Leica] Re: Pre Wash??????
From: George Huczek <ghuczek@sk.sympatico.ca>
Date: Tue, 03 Nov 1998 20:31:05 -0600

At 05:13 PM 04/11/98 -0700, you wrote:
>The important thing here is to "PREWASH" the
>film for 4 minutes in plain water. The higher speed films tend to have a
>antihalation layer that slows down processing. The prewash removese this.
>
Careful.  Prewashing requires a change in development time to compensate
for the additional time required for the developer to reach the emulsion in
the prewet film.  If the film is dry, the developer gets to work right away
on the emulsion, reducing the silver ions.  With prewet film, there is an
increase in the amount of time required to get the developer into contact
with the film.  If you prewet/prewash films, you will have to conduct your
own tests to determine the additional amount of time required to bring
about development to completion.


 _
[o] -GH