Archived posting to the Leica Users Group, 1999/01/10

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Subject: Re: Table top processors Re: [Leica] Chalk and Charcoal in HC110
From: Mark Rabiner <mrabiner@concentric.net>
Date: Sun, 10 Jan 1999 15:34:51 -0700

Roy Zartarian wrote:
> 
> The solution in the tabletop processors, as opposed to that in a
> traditional developing tank, doesn't cover the entire reel of film.
> The horizontal design of Jobo et al. would result in areas of over
> development if the rotation were intermittent.
> 
> I initially shared your concern about constant agitation until I
> attended a Jobo seminar and paid attention to the section on b&w film
> processing.  Generally a five minute pre soak in tempered water, an
> appropriate dilution of the developer, and an adjusted developing
> time with a minimum of five minutes tame the beast of
> overdevelopment.
> 
> Jobo USA has been for me a sound source of tech advice on processing.
> So you might want to get in touch with them directly as well,
> 
> HTH
> 
> Roy
> 
> 
> On 10 Jan 99 at 3:05, Mark Rabiner wrote:
> 
> > Dose any table top film processor out there, Jobo or otherwise allow
> > for intermittent agitation,snip

If an added presoak and increased dilution would help create additional
compensation why wouldn't I already be doing that it now? Or why would I
settle on just doing this as an answer to help offset the problems
created by continual agitation? I'm not trying to be argumentative or
combative, I really want to know. 

I have experimented in these presoaks and dilution's and am now using a
presoak and dilution which brings the most out of my developer/film
combination. I can see increasing in my case my developer dilution to
1/75 with continuous agitation over the 1/50 I am using in  intermittent
agitation but I can't conceive the effects equaling out. Are people
aware of the reasons behind intermittent agitation? Perhaps that could
be diatribed in a concise paragraph and a half.  
An easy answer would be for me to simply just try it and plot out the
two curves and see how closely they match.
How are you using the word "tempered" for the five minute presoak. My
thoughts could be it means either adding some carbonate or borax or
adding photo flo but I suspect you are into an area I don't know about.
I would assume Jobo USA would have a web site so I am checking that out
right now.