Re: filmscanners: Grain in Color negative Film

[Roman Kielich® <panromek@bigpond.com>]

At 14:48 24/03/2001 +0000, you wrote:

>Still, there is scope for variability in things like replenishment rates
>altering halide content, water quality (I assume the Kodalk content is 
>left as
>a variable to deal with this), and (from my tests and experience with B&W)
>agitation techniques and frequency.

replenisher keeps alkalinity and CD at desired level, halides come from the 
material.
there is no Kodalk in C41, just carbonate (plus some hydroxide in replenisher).
Color processes require more standardization, unlike BW where you can vary 
many parameters.
One machine with one process has to correctly process films from different 
manufacturers, different speed (various halides content), on commercial 
basis labs have to provide acceptable results for all sort of films using 
just one processing set (regardless of its origin). therefore they have to 
be compatible (interchangeable).

>  The latter has a profound effect on
>grain.

in BW yes, in color there is only one correct set of 
time/temp/replenishment/agitation - you set it using test strips, then 
stick to it. If you want the best results, you standardize, then maintain 
the quality. Reducing the number of variables is the easiest way of keeping 
a process within the limits.

>A belt transport minilab, deep tank with burst or dip/dunk, and DIY
>one-shot processing seem unlikely to give the same results from nominally
>identical chemistry AFAICS.

If you tweak the process, yes, you should get the same results. Each system 
requires different rate of replenishment and more/or less an anti-oxidant. 
In general, follow the manufacturer's recommendations.


rk


"Don't worry about the world coming to an end today. It's already tomorrow 
in Australia".