Re: Info for HIE e Process C-41RA

[Tom Harrison <tomh@xxxxxxxxxx>]

>>> Daniele Noris <danielenoris@xxxxxxxxx> 04/29/98 08:26am >>>
> Hi all,
> I'm new on this list, but i'm not a novice to photography.
> I need information if are some people experienced on developing Hie
> Kodak
> or SFX200, Agfa or Konica and Normal b&w film on chemical process
> C-41RA
> (for negative color). I know if I develop one Kodachrome in c-41RA I
> have
> only a disaster !!
> Can you help me ?

Attempting to process b&w film in color negative chemistry should
result in a perfectly clear piece of film (i.e. no image at all).
Here's why.

B&W processing.
First, exposed silver halide in the film is converted to a silver
image.  Next, excess silver halide is removed by the fixer, leaving
only the silver image.

Color negative processing.
First, exposed silver halide in the film is converted to a silver
image (actually, three images, one for each color).  Next,  the 
silver reacts with the dyes in the emulsion to produce the three
colors.  Then the silver image is bleached back to silver halide.
Finally, the silver halide is removed by the fixer.  Some C-41
processes use only 2 steps, combining the 2 developer steps in one,
and the bleach and fixer steps into one bleach/fix step.

Since a B&W negative image is made up of the silver image, the bleach 
stage will erase it.  You can use C-41 processing to develop B&W film,
but only if you can find a C-41 process with a seperate bleach step, and
omit it.  Or you can use the C-41 developer, and regular paper fixer
(though I can't remember if it has to be hardening or non-hardening
fixer).  But like other people have written, you are better off using
a regular B&W developer.


- -- 
Tom Harrison
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