Re: filmscanners: Grain in Color negative Film

[Michael Moore <miguelmas@qwest.net>]

Roman: I agree with you and respect your obvious expertise... the key words you
have written are "tweak the process" and follow the manufacturer's
recommendations... which most mini-labs with part time teenage help are less 
likely
to do that a pro lab... not mention cleanliness of the processor..

Mike M.

Roman Kielich® wrote:

> 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".