Archived posting to the Leica Users Group, 1997/10/26

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Subject: Re: Contrast modification in C-41 Processing
From: "Dan Post" <dwpost@email.msn.com>
Date: Sun, 26 Oct 1997 18:35:17 -0500

I thirty years of doing color film, I have found that "pushing" color film
can give you some pretty unpredictable results. Since the whole idea of
zone/contrast control is a modicum of predictability with B&W film/paper, it
just doesn't work with color.
Essentially, color film is three ( or in the case of some films, four)
sensitized layers- like three seperate films on one substrate.
Unfortunately, they all have different gammas and the manufacturer usually
has a good handle on the optimum development so that they all have pretty
much the same "slope" and the DLogE curves don't "Cross"...I have worked
several years in a Photofinishing lab since I retired and can tell you that
we go to great length to insure that Time, temp, concentration of the
chemicals, and agitation is consistant. If any of these are not, then we get
a big swing in our density graphs, and unpredictable results from the
printer- the printer is also held to close tolerances since in color, the
film and paper is optimized for use together... We used Kodak Royal paper;
we get acceptable results with other brands of film, but it really shines
with Kodak film. Likewise, when I worked in a Fuji Lab- the Fuji film really
shone above all others! That's IMHO!
- -----Original Message-----
From: Alan Bearden <healey@uclink.berkeley.edu>
To: leica-users@mejac.palo-alto.ca.us <leica-users@mejac.palo-alto.ca.us>
Date: Saturday, 25 October, 1997 7:48 PM
Subject: Contrast modification in C-41 Processing

>Has anyone tried contrast modification with color negative film and
>C-41 processing. I know that several labs furnish "push" C-41
>processing, but my question has to do with emulating the b/w Zone
>system with color negative film. Of course, one has more variables with
>color negative than in b/w processing, color shifts, etc. Any comments or
>suggestions?
>
>Alan Bearden