Archived posting to the Leica Users Group, 2001/11/20

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Subject: Re: [Leica] Acros Development Time/Process
From: David Prakel <dgp@btconnect.com>
Date: Tue, 20 Nov 2001 08:15:21 +0000

on 20/11/2001 5:29 am, Rei Shinozuka at
owner-leica-users@mejac.palo-alto.ca.us wrote:

> my xtol(1+3) times with a 1 minute prewet were very long; once i
> eliminated the prewet, my times shrank down 30%, and in fact became very
> close to those published by anchell and troop. (zone VIII == 1.25 > FB+F)
> 
> my prewetting came from old habit, advocated by picker, perhaps.  i don't
> use prewet anymore for xtol(1+3).
> 
> - -rei
> 
> 
>> From: "Don Dory" <dorysrus@mindspring.com>
>> 
>> My times did include a prewet for two minutes is water.  I will have to try
>> shorter times without the water step.
>> 

I tried to get this pre-wetting of films cleared up when I was living in
Rochester, NY. I managed to talk to a Koda-person who explained that
pre-wetting was a technique for older films with thick emulsions only. Newer
silver technology films with thin emulsions should not be pre-wet as the
development time and final quality is dependent upon the silver halide
getting developer early in the process not by displacing water from a
pre-wet emulsion.

I asked if this meant we should pre-wet films like Plus-X to which came a
sheepish reply that the Plus-X of today is not the Plus-X of yesterday. I'd
possibly pre-wet films like Tri-X, FP4, Pan F, Plus-X and HP5 only to get
tank and film up to developing temperature - if that was an issue. (I like
to develop, wash and fix at room temperature but that's another story).
Otherwise I'd treat them like modern film. I'd never pre-wet Delta or T-Max.

- -- 
David Prakel

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Replies: Reply from Mark Rabiner <mark@markrabiner.com> (Re: [Leica] Acros Development Time/Process)