Archived posting to the Leica Users Group, 2004/02/22

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Subject: Re: [Leica] Scanning B&W with Nikon Coolscan 4000
From: George Hartzell <hartzell@kestrel.alerce.com>
Date: Sun, 22 Feb 2004 18:11:40 -0800
References: <D4C64A4E-6589-11D8-9765-000393778554@netvigator.com>

Howard Cummer writes:
 > Hi Luggers,
 > I have been following the discussion of scanning B&W with Nikon 
 > scanners with great interest. Can someone (Nathan? Tina?) please send 
 > me the settings used to scan Tri X negatives cleanly on a Nikon 
 > Coolscan 4000. [...]

I'm still struggling with it.  My main problem with my scans of "real"
b&w films (e.g. delta 3200, tri-x, ...) is that I end up with *much*
more grain in the scan than I see in an old-fashioned enlarger-based
print of the same image.

I've come to attribute the problem to two factors, a) "grain
aliasing", the unfortunate interaction of the grain in the film with
the sampling frequency of the ccd grid and b) the highly collimated
LED light source in the Nikon scanner, which accentuates grain, dirt,
scratches, etc....  If I'm understanding everything correctly, the
aliasing problem ought to be similar for any (e.g.) 4000 spi sensor
although the various systems' hardware/software might make a
difference.  The problems caused by the Nikon's light source are
definitely avoidable, the diffuse illumination used by my LeafScan 45
gives better/different results.

One "solution" to the aliasing problem is to scan with the image
_slightly_ out of focus, then use fancy sharpening to tighten up the
real features in the image.  The theory is that it eliminates the
highest spatial-frequency features (like the anti-aliasing filter in
front of many digicam sensors) w/out messing up the real features in
the image.  I can't claim that I'm completely happy with the
technique, it's a work in progress, I'm hoping it'll give me better
results with my grainy stuff.

I'm also searching for opportunities to try some of the other 4000 dpi
scanners (e.g. the microtek/polaroid and/or the canon) and see if
they're really different.

g.
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In reply to: Message from Howard Cummer <cummer@netvigator.com> ([Leica] Scanning B&W with Nikon Coolscan 4000)