preserving / ressurecting old docs?

From: Brian Knittel <brian_at_quarterbyte.com>
Date: Sat Jun 23 02:34:00 2001

Pardon me if I missed someone raising this issue yesterday, but
if you're scanning grey level images, it might be worth seeing
what happens if you raise the resolution and switch from
grey level to black & white (line art) scans -- one
bit per pixel. Then you can raise the resolution from 100x100 to
300x300 (9 times the pixels) , and end up with only a 12%
increase in filesize. Photos & halftoned images don't suffer
this well, but the text and line art will be much better off.

This requires you to take some care setting the contrast
and black level when preparing to scan, though.

Alternately you could scan at 300x300 greyscale (8 bits per pixel )
and run the pages through a filter to reduce the bit depth
from 8 to say 2 or 3. This would only be feasible if you could
automate that process, though.

Before embarking on this huge project, it might be worth
trying a few different techniques to obtain sharper images while
keeping the file sizes reasonable.

Brian
Received on Sat Jun 23 2001 - 02:34:00 BST