Archived posting to the Leica Users Group, 2002/01/05

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Subject: [Leica] Re: [OT] Jobo CPE-2...
From: Rolfe Tessem <rolfe@ldp.com>
Date: Sat, 05 Jan 2002 09:00:38 -0500
References: <200201050623.WAA16833@mejac.palo-alto.ca.us>

> Date: Fri, 4 Jan 2002 21:55:19 -0500 (EST)
> From: Rei Shinozuka <shino@ubspw.com>
> Subject: Re: [Leica] [OT] Jobo CPE-2...
> Message-ID: <200201050255.VAA06302@tigercat.nyfir.pwj.com>
> References:


 
<snip>
> 
> on the subject of developer exhaustion, Anchell goes even further:
> 
>   Although it is true, as Kodak claims, that 100ml of _undiluted_ D-76
>   is sufficient to develop 8x10 inches of fim, it may not always be
>   enough to develop the film to its fullest potential.  The amount of
>   solution  required to cover the film's surface should not be confused with
>   the amount ot developer required to fully develop a roll of film.
> 
>   For example, 100 ml of solution will cover one roll of 35mm, 36
>   exposure film in a JOBO CPA-2 processor.  However, to _ensure_
>   full development of _all_ images on the roll at least 250 ml of
>   undiluted D-76 should be used, no matter what any manufacturer says
>   to the contrary.



<snip>



>                      - Anchell and Troop, The Film Developing Cookbook p. 31


This is clearly not true, at least in the general sense, since the 
volumes Jobo recommends as the minimum needed are the ones that are used 
when processing C41 or E6. With my 2500 series reels on an ATL-1000 
those numbers are 170ml for one roll of 35mm film plus a "filler" to 
fill up the bottom of the tank, 250ml for two rolls in a 4218 (the 
smaller one) tank. But interestingly, the number is only 160ml for 
anywhere from 1-6 sheets of 4x5 in a 4218 tank. (Yes, one sheet requires 
the same volume as 6 sheets). Of course, 6 sheets of 4x5 equals one and 
a half sheets of 8x10. Also, the amount of solution needed for either 3 
or 4 rolls of 35mm is the same -- 500ml -- and only 600ml is needed for 
5 rolls (in the larger 4219 tank). FWIW, the bottles in the ATL-1000 
hold a maximum of 750ml.

So, to have a workable strategy for using dilute B&W developers, one 
needs to take the Jobo minimums into account along with the tank (or 
motor) maximum, along with the developer manufacturer's recommendations. 
(The numbers listed above apply to the ATL-1000 and probably to the 
newer ATL-1500 as well, but other Jobo processors will undoubtedly have 
their own requirements.)

On the subject of Xtol, it is interesting that Kodak used to publish 
times for 1:2 and 1:3 dilutions but has removed that information from 
its web site. Here is what the company has to say on the matter:

- -------------------------------------------------------------------
Note:Kodak has tested XTOL Developer for long-term keeping by using 
typical equipment and procedures. Results indicate that mixed XTOL 
Developer stored for one year at room temperature (70°F [21°C]) in a 
full tightly closed bottle provides satisfactory results with Kodak 
black-and-white films when used at full strength. Some customers, 
however, have reported problems with developer stored for periods 
between six months and one year. Most often the problems related to loss 
of developer activity when customers were using a 1:3 or 1:2 dilution of 
the developer to process KODAK T-MAX 100 Professional Film.
To help ensure best results, we have changed our recommended shelf life 
and dilutions for XTOL Developer. The new recommendations are the same 
as those for KODAK Developer D-76 (full strength and 1:1). The change in 
recommendations does not indicate any change in the formulation of the 
developer. If you have been consistently obtaining satisfactory results 
with diluted developer and you use the mixed developer before keeping 
characteristics can become a concern, you may want to continue your 
current procedures. However, Kodak publications will no longer include 
development recommendations for the 1:2 and 1:3 dilutions of the developer.
- -------------------------------------------------------------------

To me, it is clear that Kodak is now recommending against Xtol dilutions 
greater than 1:1 or, at a minimum, says you do so at your own risk.

- --
Rolfe Tessem
rolfe@ldp.com
NYC




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