preserving / ressurecting old docs?

From: Mark <mark_k_at_totalise.co.uk>
Date: Fri Jun 29 14:13:13 2001

Hi,

On Fri, 22 Jun 2001 Bill Bradford wrote:
> > Your best bet is to take the books and have the binding cut off
> > professionally. Then scan in the pages one at a time (not two). I
> > personally believe Adobe Acrobat is the best way of doing this. Although
> > I realize there are people here that are against Adobe Acrobat.
>
> I'm scanning them in as 100dpi grayscale GIFs, then I will convert to
> other format(s) and eventually to PDF. Scanning directly to PDF with
> HP's software produces horrible output with compression artifacts.

100dpi is too low a resolution; it is little above monitor screen resolution,
and small text may be illegible. Future OCR-ing of the scans would likely be
unsuccessful too.

A better alternative is to scan at a reasonably high resolution in monochome
(two colours, black and white), say 300dpi or 600dpi.

Most viewer software renders the scanned pages on-screen in greyscale anyway,
and output when printed on paper is far better. Bilevel images compress
losslessly very well, *much* better than greyscale.

If there is spot colour in the original, it would in theory be possible to
scan at equally high resolution with little impact on file size. (E.g.
VAX/VMS manuals have some text in red, so there are essentially three
colours; white, black and red.) You would have two images which could be
overlaid on each other. If anyone knows of a software package that will work
like that, please let me know.

Depending on your scanner and the paper thickness, you may find that text from
the opposite side of the page "shines through", especially in greyscale
images. You can put a sheet of black card or similar on top of the page to be
scanned to reduce this effect.


-- Mark
Received on Fri Jun 29 2001 - 14:13:13 BST