I guess I think in terms of scanning these days, where I was assuming
the brightness range of interest was within the range of the film. In
which case I see more muddyness from print negatives because the
brightness range is more compressed compared to chromes, so I get
quantization error limiting tonal variation. I've been known to tie my
tongue in knots before, so it may *sound* like I'm contradicting
myself, but just pay attention to what I was *thinking*, not what I was
*saying* and it should be all clear. :-) (such statements work great
with the SO, don't they.) OK, Let's see if I can dig myself out here,
and not contradict myself too much.
With respect to chromes, I should have said (instead of less contrasty,
although it is) that 100F seems to have smoother tonal variation than
Velvia, but that may be more due to grain structure than contrast. So I
made a slip there. Sometimes overly contrasty/sharp films (of the same
type) have more distinct grain but less smooth tones. But let's compare
print vs. slide.
If we are on the edge of the film exposure range, close to clipping,
then certainly print films will give more detail in that region. If
contrast is defined as the slope of the density vs. exposure curve,
where a steeper slope means higher contrast, then the contrast of slide
film is very reduced at the extremes compared to the same exposure
value of print films. While slide films have higher contrast in the
mid-range. Hence you could say that print film has more contrast
than chromes in the exposure region where the chrome density curves
flatten out. (compare the curves of E100VS to Supra 100 at
<http://www.normankoren.com/zonesystem.html>.)
However, granularity also plays a role, and if you add the nature of
granularity in the exposure extremes, the picture probably gets more
complicated. If you notice the curve of E100VS, even the curves of the
colors flatten out in different ways, so maybe one color shifts at the
extremes, or saturates sooner. This is where Astia is more forgiving,
for instance, because of the way Astia behaves at the exposure
extremes.
So my view is that higher contrast gives more density variation and is
able to give more subtle tonal variation in the presence of noise (like
grain structure). The question is, what is the exposure value and where
does that place you on the density vs. exposure curve and what is the
slope at that point compared to its granularity. In the mid-range,
slides have a steeper slope (more contrast), at the extremes, print
film has more slope (more contrast). If they have similar grain, then
slides win in the mid-range, negatives win at the extremes. (does
granularity vary over the exposure range also?)
At 04:50 PM 9/17/2002, Moose wrote:
> Am I missing something, or are you disagreeing with yourself?
See above, and yes, maybe.
> w shumaker wrote:
>> <>to get increased tonal subtlety you need a higher contrast film
>> Provia 100f is less contrasty and can potentially provide smoother
>> gradations.
> <snip>
> High contrast film maps any given range of brightness in the scene
> into a narrower range of density on film than does low contrast film.
I guess I understand the curves to mean that higher contrast film (like
chromes) maps a narrower exposure range into a certain density range.
Lower contrast film (negatives) map a wider exposure brightness range to
a density range. Have I got that wrong?
> Thus, whatever minimum difference of density can be discerned or
> measured on the film represents a narrower range of brightness in the
> scene on low contrast film than high contrast. More density
> increments for a given range of scene brightness is like more dpi in
> a scan, it carries more information detail.
Given I don't follow the first statement, I'm confused, but I think we
are trying to say the same thing, and thinking takes precedence over
saying, right. :-)
For me and scanning film, overall, I think it is grain that makes
the difference as long as we match the scene brightness range optimally
to the film exposure range. An optimally exposed low grain slide film
on a narrow brightness range (4 stops, maybe 5) will yield best results.
An optimally exposed low grain print film will yield best results for a
higher brightness range (7 stops, maybe 8). Printing at the lab with a
machine print, blowout city.
Wayne
< This message was delivered via the Olympus Mailing List >
< For questions, mailto:owner-olympus@xxxxxxxxxxxxxxx >
< Web Page: http://Zuiko.sls.bc.ca/swright/olympuslist.html >
|