On Tue, 16 Apr 2002 16:58:52 +0200 Alex Zabrovsky (alexz@zoran.co.il)
wrote:
> Sorry Tony for my natural stupidity, didn't get your point.
> Do you mean negs would block dark areas completely whilst slides would
> still
> resolve something ?
Dark areas of the image are unexposed areas of film. With transparency,
these are areas of maximum dye and attenuate scanner illumination to the
point where CCD noise can be a problem.
With negs they are areas of minimum density of dye , so pass the maximum
amount of light and avoid the CCD noise issue (CCD's produce random noise
when unilluminated).
You may get CCD noise in the brightest image highlights, with negs (dense
dye), but this is usually a lot less obtrusive.
It's not all good news though. You may also see a rather objectionable
amount of grain in negative shadows, as the minimal exposure does nothing
to overlay and diffuse grain effects. EG the vile, dark green, grainy look
of underexposed images printed conventionally. But I find scanning copes
much better with this than C41. If you're unlucky, you may get grain
aliasing there too.
Regards
Tony Sleep
http://www.halftone.co.uk - Online portfolio & exhibit; + film scanner info
& comparisons
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