John Rudiak (wizard@laplaza.org)
Sat, 23 Jan 1999 13:12:29 -0700
When we point our cameras at something to photograph, the scale of light
intensities in real life is linear. As soon as this is imposed on film, this
linearity is distorted as indicated by film curves, In general there is a
compaction of tone spacing in the shadows and highlights. This effect is
amplified in the process of producing enlarged negatives. While this can be
minimized by appropriate choice of film stocks, ie choosing films with the
"straightest" curves, and placing the visual information on the straightest
portion of these curves, it is never totally eliminated and there is always a
tonal distortion from the original negative. This doesn't take into account
the effects of going through more than one lens system.
In my opinion, the most faithful results are obtained by making the
interpositive on a graphic arts film utilizing the middle portion of the
"curve" and then making the negative on a camera film such as FP4.
John Rudiak
www.johnrudiak.com
Judy Seigel wrote:
> On Sat, 23 Jan 1999, Carl Weese wrote:
> > I can't think of any reason why properly made enlarged negatives
> > shouldn't print approximately the same--in terms of formula and printing
> > time---as in-camera negatives.
>
> I can think of 2, although they may not be overriding...
>
> The film base plus fog on the lith film is VERY low, but can go
> rather high on camera film.
>
> The thickness of the film itself could also count, lith being .03 or
> at most .04 (if I have the decimal in the right place), the others
> generally around .07, which could be more than twice as thick.
>
> Judy
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