From: Jeffrey D. Mathias (jeffrey.d.mathias@worldnet.att.net)
Date: 05/25/00-11:06:16 PM Z
FotoDave@aol.com wrote:
> ...
> The scanner sensor responds similar to the theoretical desired value, thus it
> is best to scan positive than negative (because in a negative, the dark value
> is scanned to have small separation but the dark values are actually the
> highlights where you need good separation)....
However, if the negative is exposed properly and developed less than
typical for Pt/Pd, then the scanner does record well (HP ScanJet
6300C.) It is very important not to have too much density in the
original negative because of the scanning lack of separation as you
mention and because of increased noise. I have had no difficulty
scanning a properly made negative and prefer it to results of scanning a
print. The film offers much more information.
> ... We might [not] need all 80
> values for the highlight, but you can see it is certainly more than 10
> "zones" that you have.
I was saying 10 tones per Zone. For example, a palladium print can
easily demonstrate 12 Zones. If the upper highlights (say Zone IX
through XII) are considered that could be comprised of 40 tones (likely
less because Zone XII would probably only really have 2 or 3 tones).
The question concerns how many tones are necessary to accurately
distinguish the upper highlight subtleties of a high key image.
As you mention, the eye is very keen at discerning high tonal values.
There must be a point, a number of tones, at which the eye has plenty of
information to accurately interpret the information. All the tones are
presented simultaneously in the image and subtleties easily
distinguished. The situation is very different from that of music where
a definite set of notes provides complete control. However similar to
the music, I believe there is a finite set of tones that can provide
complete information.
>... That is why if you have to scan negative, increase the contrast, scan in
> 12-bit, and the adjust the curve (or the scanner software might support curve
> too) before you change it to 8 bit. Scanning in 8 bit will cost too much lost
> in shadow....
Agreed. However rather than thinking of increasing contrast, I prefer
to think of adjusting the range to just before clipping occurs.
> ... You might want to try duotone / multitone as suggested by
> Dan. ...
I want to avoid multiple printing, a major concern being that the paper
changes size when wet processed. Also coating becomes more problematic
after the paper has been processed. Of course I could give multiple
exposure prior to processing (which I believe is Dan's suggestion), but
I prefer one exposure through a set of masks rather than multiple
exposures, preferring to add the densities of negatives rather than add
the light transmitted through the negatives. Either method is
acceptable, however a single exposure does reduce the chance of effects
from lengthy repeated exposures, humidity and temperature control.
>... I guess the bottom line is where you want to place your control: in computer
> (through curve), in negative (through mask), or in the final print stage
> (through duotone / tritone)....
I was hoping to get control on the computer, but am convinced that I
will have to use the negative/mask. I do not wish to do it in the final
print, although multiple exposures prior to a single processing is not
ruled out.
>... Another method which I haven't seen discussed (in technical details) before
> is to use lith film for your interpositive with careful place of tone and
> control of contrast....
Tried it and strongly prefer the use of a film like Kodak 4127 with lith
film masks.
> ... by careful control, you can
> achive what you want without masking (except of course when the image
> lighting specifically requires it).
Not exactly true. Limitations of the film make it impossible to get the
exposure and contrast and correct negative densities. Even the masks
will not get it exact, but do get it closer. This is the reason that I
am learning to build digital negatives, so that I can manipulate the
values the way I would like them. With film, one is limited to the
materials used, the exposure, and the development. With digital, curves
and adjustments can be made that are impossible by the analog
techniques. However, digital has its own challenges and limitations.
-- Jeffrey D. Mathias http://home.att.net/~jeffrey.d.mathias/
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