Archived posting to the Leica Users Group, 2002/03/26

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Subject: RE: [Leica] Re: dMax and Dyanmic range - scanners
From: "Austin Franklin" <darkroom@ix.netcom.com>
Date: Tue, 26 Mar 2002 12:07:46 -0500

> Austin & John:
>
> What do scanner manufacturers mean when they say that their devices have
> a high DMAX?
>
> Are they claiming a high dynamic range, yet use the term DMAX?
>
> Jim
> http://www.hemenway.com

Hi Jim,

dMax means DENSITY max, and dMin means DENSITY min.  That has nothing to do
with dynamic range at all.  dMax is the darkest relative density value that
the scanner can detect and dMin is the lightest relative density value that
the scanner can detect.

The highest dynamic range the scanner can have is determined by the number
of bits the scanner uses to represent the density values.  The actual
dynamic of the scanner may be lower...but typically, the A/D is matched to
the analog section of the scanner so they should be pretty close.

Austin

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