[filmscanners] Re: Lack of contrast in the (raw) scans from VueScan ?

["Bob Shomler" <bob@shomler.com>]

At 10:55 PM 4/27/2002 -0700, you wrote:
>I have had a Nikon LS-30 scanner for over a year now and until
>recently it was being used occasionally to scan images that I needed
>to post to a web page or send via email. A couple of months ago,
>though, I started looking into how to capture the "most" from my films
>for archival purposes and was surprised by the initial results from
>using VueScan (which I had hoped would give me more than the 8bit
>pixel depth I am getting from NikonScan.)
>
>I am using VueScan 7.5 (beta ?) and NikonScan 3.1.0, and the "default"
>settings for VueScan generally produces images that are washed out and
>lack in contrast.  ...    Are there any obvious
>controls for VueScan that I need to be changing (other than the film type
>& scan resolution -- I don't seem to be able to find a manual exposure
>or Analog Gain control.)

Vuescan is, as you have written, designed to get all that the scanner can get 
from film.  Default black and white point settings extend far wider than you 
might want in a final image.  Changing Vuescan's color white and black point 
percents can help here.  However having Vuescan save 48-bit mode tiff and 
making these adjustments in Photoshop 16-bit mode is preferred by many.  (This 
is what I do with my LS-30 scans.)

If you're using 7.5 (beta or no point release) you need to get a newer release. 
 Some significant "dull image" problems were fixed in 7.5.2.  If you're at 
7.5.11 or later you're probably OK, otherwise download the latest (7.5.22).

Set Device->Option Types to advanced to see many of the controls, such as for 
exposure (which will be found in the device tab).

Also check out the Advanced Workflow Suggestions in the Vuescan help file.

I assume in this that your reference to raw files is to the Vuescan "Save TIFF 
File" results, not the raw scan data from the scanner (Files->Save raw file), 
which will look flat (and negative inverted for neg film).

>- Can VueScan reliably/repeatably get 10bit raw readouts of a given
>  pixel or are the extra two bits simply random values being read
>  independent of the value of the pixel ?

AFAIK the 10 bits are what the scanner delivers.  I have not had problems with 
this on my LS-30.  You sometimes can get a little improvement (noise reduction) 
by setting Device-> Number of passes to 2.  See also the "Maximizing Image 
Quality" section of the help file.

Bob Shomler
www.shomler.com

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