Scanning microfiche?

From: Clint Wolff <vaxman_at_uswest.net>
Date: Sat Jul 29 17:26:47 2000

On Sat, 29 Jul 2000 CLASSICCMP_at_trailing-edge.com wrote:

>
> As to the quantities, there seem to be about 250 fiche sheets in a one-inch
> stack, and my stack is about 18" high. That's 250*18=4500 pieces of fiche.
> And each piece of fiche is somewhere between 50 and 200 printed pages of text;
> that's about 450 thousand printed pages, by my calculations, using an average
> of 100 printed pages per fiche.
>

Hmm... My previous estimate was wrong, I must have close to 10000
fiche...

> I was thinking (I could be wrong) that a scanner could take in the whole
> 4" x 5" microfilm sheet at once, and then I could write some software that would
> parse the whole-sheet image into frames, do some automatic cleanup on each
> individual frame, and compress. Am I walking down the wrong path?
>

The problem with this is the size of the imager... A 4" wide scan bar
at 10000 DPI (probably low) is 40,000 pixels. Most modern scanners have
a 8" wide scan bar (element) at 600 DPI (real optical resolution)
thats only 4800 pixels. So even with magnification, the scanner
elements aren't big enough...

I have contemplated building a contraption (enlarger) that would
focus 1/15 or 1/20 of the fiche onto a translucent screen, and
scanning that. Unfortunately, as Chuck(?) pointed out, the mind-
numbing task of repositioning and refocusing for each fiche is
out of the question.

On the topic of drum scanners, will they read a semi-transparent
item such as a fiche? The only one I have ever seen was on TV,
and they were coping one dollar bills to show how easy it was
with high end technology...

clint
Received on Sat Jul 29 2000 - 17:26:47 BST