Archived posting to the Leica Users Group, 1997/11/15

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Subject: Re: scanning
From: Thomas Kachadurian <kach@freeway.net>
Date: Sat, 15 Nov 1997 09:17:58 -0500

Patrick:

Perhaps my view is jaded because I see so much of my work as CMYK druum
scans, but I have a LS-1000 supercoolscan and still find it lacking with
Slide film. I can get a great halftone, but to make a CMYK file a good
PhotoCD is much better. 

Tom

>My answer may be less than entirely useful to you, because you already have
>a Coolscan II.  But the problem you're experiencing is that the Coolscan II
>has a small dynamic range, too small for transparencies.  The Coolscan II
>is a 24-bit scanner, where the LS-1000 Supercoolscan or the Sprintscan 35+
>are 36-bit scanners.  Since the dynamic range is small, the scanner can
>capture either highlight detail or shadow detail -- not both.  It sounds
>like the software has made the choice to capture the highlights and leave
>the shadows dark.  I don't have a Coolscan II, so I don't know if you might
>be able to use an exposure setting in the scanner software to tell it to go
>ahead and wash out the highlights and look into the shadows.  If the driver
>and hardware let you do this, then you could make two scans, one for the
>highlights and one for the shadows, and combine them in a complicated way
>in Photoshop.
>
>You're probably already aware that if you use a film that has a smaller
>dynamic range (is less contrasty), like a color negative film, you'll be
>able to get more shadow detail in your scans.
>
>PhotoCD's also supply 24-bit images, but the transparencies are usually
>scanned with scanners that have a greater dynamic range than 24 bits.  Here
>a lot depends on the operator.  A poorly-made PhotoCD from a cut-rate shop
>will have poor color correction, poor exposure values, dust and fibers on
>the images, and will be very frustrating for you -- you might well be able
>to do better on your Coolscan II.  A well-made PhotoCD from a reputable
>shop will be very good and will cost extra.
>
>Polaroid is reputed to have the most flexible software of the consumer film
>scanners.  Certainly you can perform color correction and brightness and
>contrast and curves in the scanner itself with it.  I certainly recommend
>it, if it's not too late for you to switch.
>
>-Patrick
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