>I have a good film scanner (Polaroid 120) ...
No, you do not have a good scanner; that's a big part of your problem.
Many people go to CompUSA or Best Buy and buy a scanner, and they believe th
ey
have a "good" scanner. There is, almost by definition, no such thing as a
"good" consumer-grade scanner; decent scanners start at about $17,000 and go
up
to about $320,000. I've used $320,000 scanners, and the image you get is ver
y
crisp.
Back to your problem.
Consumer-grade film scanners suck. Not to put too fine a point on it, it's a
fact of life.
If you want a crisp scan from most consumer-grade scanners, I suggest you re
ad
about and become comfortable with Filter->Sharpen->Unsharp Mask. Unsharp
masking (USM) is a technique for sharpening a soft image.
Some scanners do unsharp masking during the scan; check to see if your scann
er
has this option. Scanners that do it will produce crisper scans than scanner
s
that don't. If your scanner doesn't, you'll need to unsharp mask your image
in
Photoshop after it's scanned.
Unsharp masking is part art, part science. There is no set way to use it whi
ch
works for all images.
Generally speaking, however:
The Unsharp Mask filter works by exaggerating areas of high contrast--ie,
edges. This gives the appearance of sharper edges, and increases the apparen
t
overall sharpness of the image. While it can't make a blurred or out-of-focu
s
image sharp (nothing can do this), it can dramatically increase the percepti
on
of sharpness. And unsharp masking is a requirement to get good-looking image
s
in print.
The Amount slider dictates how much edges are increased in contrast. If the
value in this slider is too high, the image will appear to have "halos" arou
nd
the edges.
The Radius slider determines how wide the area of enhanced contrast is aroun
d
edges. In general, the amount you put in the Radius field depends on the
resolution of the image; the higher the resolution in pixels per inch, the
wider the Radius.
A good place to start is (image resolution/200). If the image is screen
resolution--100 pixels per inch or less--try a Radius of 1. Increasin ghte
Radius will also create undesireable halos around edges.
If you are sharpening an image which will be printed on a printing press, an
d
your image is the recommended resolution (twice the frequency of the halfton
e
you will be using to reproduce the image on press), use a Radius of (halfton
e
screen/100). So, for example, if your image is being printed on press with a
150-line-per-inch halftone, use a Radius value of 1.5.
The Threshold command determines how far apart two neighboring pixels must b
e
in tonal value in order to be sharpened. I usually start with a Threshold of
3.
Lower Threshold values exaggerate noise along with edges; higher values don'
t
sharpen noise, but also produce more muted sharpening overall.
Note that if your image is intended for print, you should set the Amount val
ue
so that the image looks slightly over-sharpened on your screen! This is beca
use
the process of halftoning the image for print decreases the apparent sharpne
ss
of the image (which is why all images should have USM applied if they are go
ing
to be used for print).
>My flatbed is somewhat older (Microtek Scanmaker III with Scanwizard) but
>still decent.
That scanner wasn't particularly good even when it was brand-new. Sorry...
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10-02-04 - 05:14 PM 
