Archived posting to the Leica Users Group, 2001/04/02

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Subject: Re: [Leica] [leica] Help re VUESCAN
From: Henning Wulff <>
Date: Mon, 2 Apr 2001 09:40:51 -0700
References: <005401c0bb85$cf7d1720$>

At 11:01 AM -0400 4/2/01, Dan Post wrote:
>Any VUESCAN users out there?
>I have been using it for my Minolta Scan Dual for over a year, and with
>astounding results- at least for me! I get such large high resolution scans
>from  the scanner with VUESCAN, that I am afraid that I would not be able to
>handle files made with a 4000dpi scanner!
>I mean, when you can get a 450MB TIF file, that resolves the grain before
>the pixilation is evident, what more can you ask for? Molecular images of
>the silver grains? :o)


I can't help with your flatbed scanner problem, but the above 
statement caught my eye. The Scan Dual has about a 2800 dpi sensor 
and output (or is it 2500?). Assuming 2800 for the moment, which in 
real terms means that it can resolve less than 2400dpi max (there 
will be some losses at this stage), it would output a file 2800x4200 
dpi, or so. That gives about a 35Mb file, uncompressed at 
8bit/channel. I don't know whether the Scan Dual can output a raw 
file at 16bit/channel with possibly 12bit/channel of info, but if it 
could, that would result in a file size of 70Mb. In practice, due to 
the above real limitations in resolving power and dynamic content, 
about half of the file, or about 35Mb, is spurious information in the 
first place. Interpolating this up to 450Mb might be useful for 
certain output purposes, but it still won't contain more than 35Mb of 
info. In any case, you shouldn't use the scanner or scanning software 
to do such interpolation; Photoshop or Genuine Fractals does a better 

That 2800dpi sensor, by the way, is in no way capable of truly 
scanning grain on any of the better emulsions. With Tri-X you will 
get a clumping that resembles grain, but it is more or a Moire effect 
of interference than a true rendition of the grain. 8000dpi drumscans 
can't resolve Delta 100 grain.

- -- 
    *            Henning J. Wulff
   /|\      Wulff Photography & Design
  |[ ]|

In reply to: Message from "Dan Post" <> ([Leica] [leica] Help re VUESCAN)