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[OM] Scanning DMax requirments, was: Don't cry, just do it! [was Velvia

Subject: [OM] Scanning DMax requirments, was: Don't cry, just do it! [was Velvia 50 replacement]
From: Chuck Norcutt <chucknorcutt@xxxxxxxxxxxxxxxx>
Date: Mon, 11 Jun 2007 05:50:37 -0400
Thanks for the footnote.  I learned something here.  In thinking of 
color negative's ability to capture a wide range of subject brightness I 
hadn't mentally translated the mapping of that range into a smaller film 
density range and thus into a smaller DMax requirement on the scanner. 
I should have since Ctein's book on photo restoration makes a similar 
point on scanning prints.  Since prints have a low brightness range 
neither high DMax (nor high resolution) are particularly important in a 
flatbed scanner used for restoration image capture.

Chuck Norcutt

Moose wrote:

> 
> * Assuming for simplicity that the scanner is capable of capturing the 
> whole range of densities on the film. This is not a practical problem 
> with color neg film, as the density range is considerably smaller than 
> for slide and conventional silver B&W film, due to the orangeish mask in 
> CN film. CN captures a wider range of subject brightness than reversal 
> film, but maps it into a smaller film density range. As an aside, this 
> means that the search for the scanner with the highest DMax is not 
> important for CN film, but hardware resolution of density differences 
> and a bit depth of output to contain that detail that are more important.
> 
> It also assumes that the scanner is profiled, which is at issue in other 
> parts of this thread, but not at issue in this theoretical example.

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