Date : Fri, 20 Jun 2008 15:07:13 +0100
From : dllm@... (Dave Moore)
Subject: The Micro User
> On a related note, does anyone have any advice on nondestructively
> scanning old mags like these?
No useful advice from me I'm afraid - unless the mags in question are very
thin, I tend to just rip off the binding and separate into individual pages.
If you try to scan thick mags that are still bound, no matter how many
Encyclopedias you load on top of the scanner (to weigh the pages down) I've
found that you'll always end up with sub-standard scans (e.g. missing portions
of detail close to the spine, wonky edges, blurry areas etc).
Obviously, on thinner mags you can just remove the staples.
Oh, and I'd add that using an A3 scanner is almost a prerequisite (or at least
an "oversized" A4 scanner) ... saves the hell of a lot of fiddling around
trying to line-up/align pages that feature detail around all four edges.
> I've got an almost complete collection of Acorn Users from 1982-1993,
> and I'd like to make decent scans of them for archival purposes at
> some point.
Side note: Dave Edwards has two full sets of Acorn Users and has offered to
tear apart and scan one complete set. All he's asking for is TEN people to
express their interest and he'll get going <ref:
http://www.stairwaytohell.com/sthforums/viewtopic.php?p=12472>. So I urge as
many people on the list as possible to contact Dave and offer him some
encouragement!! (either via the contact form @ acornelectron.co.uk, or via the
STH forum)
> How do people handle the curvature introduced by perfect binding, and
> what file formats/resolutions are regarded as adequate?
>
> I know Al Kossow (at <http://bitsavers.org>) prefers 400 dpi scans
> saved nonlosslessly because OCR packages tend not to like the
> artifacts introduced by JPEG compression. This would get a bit
> unweildy for full colour images though. Is JPEG2000 better in this
> regard?
With reference to the mags I've scanned for http://mags.acornpreservation.org
(which is everything except the Micro Users) ...
Though the online versions are 150dpi JPEG, I mainline offline backups which
are 300dpi uncompressed PNG.
Mono pages are scanned as greyscale. Coloured pages are scanned in using 24
bit colour (even if the only colours used are black, white + one other). I
*may* reduce the colour depth of such "tri-colour" scans to 64k colours or 32k
colours, but rarely to 256 colour (aka 8-bit) as I'm seldom happy with the
results.
As for the scans on the main http://www.acornpreservation.org website (which
comprise scans of packaging, documentation, brochures etc) these are 600dpi
JPEG, but again, I also keep lossless [600dpi] scans on external HDD & DVD-R.
(I can't help but feel 600dpi is overkill for magazines, as you'd end up
requiring terabytes and terabytes of space to store the lossless versions).
--
Dave.