Archived posting to the Leica Users Group, 1998/05/01

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Subject: [Leica] Re: Exploring Leica
From: Michael Leitheiser <>
Date: Fri, 01 May 1998 19:04:42 -0700

See below the comments of the inimitable and eminently knowledgeable Erwin
Puts on the film/developer issue........

At 10:58 AM 4/7/98 +0200, you wrote:
>>Has Erwin ever compared film/developer combinations, Pyro, Windisch, fx1,
>>TechPan and Technidol, etc. to evaluate best combination(s) of "sharpness"
>>and/or range to make maximum use of Leica glass?  In reading the Formulary
>>catalog I see claims of developers capable of recording a 15 stop range
>>with fine grain and high "acutance".
>Of course I did. Would you like to expose film with such a marvelous
>instrument as an M Leica without making sure the potential capabilities of
>the optics/mechanics are not being degraded by emulsion/chemical
>But here as elsewhere, we must part from history. Old wondermixtures and
>secret formula have no place in the actual world of emulsion science.
>Windisch, Pyro etc tried to get high acutance effects with films not made
>for this exercise. In general now the high acutance era is gone. Not that
>acutance is no longer important. No, most films and developers will produce
>slight acutance effects. Many developer formula will have less impact on
>the endresults nowadays, because films are more robust and will not react
>very sensitively to different developers. Ilford for instance states that
>their excellent Delta line is totally unsensitive to developer
>characteristics as the chararteristics of the film are as it were inbuilt.
>I used many developers from Rodinal, through D76 to XTOL on all modern B&W
>films (From Agfa APX 25 to Fuji Neopan 1600). The differences are very
>visible no doubt about it. But again, you need at least a 12 to 15 times
>enlargement to see it.
>My conclusions?
>Techpan and Technidol/Rodinal or whatever is a combination with a stunning
>resolution and richness of details. It is no acutance champion.
>Rodinal is not my favorite: its gives tight grain, but very stong clumps of
>it. It enhances the sharpness impression but ruins the fine gradations of
>small details.
>My preferred combinations: Agfa APX 25 and Paterson FX39 or XTOL. Ilford
>PanF lLus and 100Delta in the same developers.
>These developers have a very good balance between acutance and gradation
>and willbringout the bst from leica lenses. The APX 25 and the PAnFPlus are
>in the same league as Techpan but bring sharper results and finer tonality.
>It is impossible to get a 15 stop range with any film/developer
>combination. To accomodate this range you need a Contrast Index so low that
>any sharpness/acutance or contrast is developed out of the film.
>Here as everywhere there is a balance: a steep curve gives gradation , but
>a smaller range of stops. A good acutance needs some grain forming activity
>and that ia against the quest for very fine grain.
>One must remember that a 35mm negative is a different breed from a 120 or
>large format negative and many of the Zone System ideas will not work on a
>35mm unless you adapt to the characteristics of the small emulsion area.
>To sum up: try APX25 and XTOLand the best of Leica lenses is at your feet.
>After this: use this combination until you are sure you know everything
>about it.
Mike Leitheiser

"When the trout are lost, smash the state."
                                   Tom McGuane