Archived posting to the Leica Users Group, 2001/07/24

[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]

Subject: RE: [Leica] Scanning
From: "Austin Franklin" <>
Date: Tue, 24 Jul 2001 09:06:21 -0400

> Austin Franklin writes:
> > 2700DPI only approaches the limit of quite
> > grainy films.
> 2700 dpi is 53 lp/mm.  It is very difficult to achieve 53 lp/mm
> with handheld
> photographs because of camera shake (and most of my photos are handheld).

I believe your premise is flawed.  You need to sample at slightly more than
2x the maximum frequency you want to acquire.  A scanner IS a data
acquisition system.  53 lp/mm is 106 lines/mm, which, as you say, is ~2700
SPI.  In order to assure that the scanner can actually "acquire" all the
lines, both black and white (which is what a line pair is), you would need
to sample at > 5400 SPI.

Replies: Reply from "Mxsmanic" <> (Re: [Leica] Scanning)