This message contains 7 messages on the same topic.
Moderator
XXXXXXXXXXXXXXXXXXXXXXXXXXXX
Message 1:
Travis,
We haven't had any problems with mylar interfering with scan quality. It is
possible, however, that the there is a very very slight focus issue due to
the thickness of the plastic. For our purposes, this has been undetectable.
Matt
Matthew A. Knutzen
Assistant Chief, Map Division
The Humanities and Social Sciences Library
The New York Public Library
5th Avenue & 42nd Street, Room 117
New York, NY 10018-2788
[log in to unmask]; 212-930-0562; fax 212-930-0027
http://nypl.org/research/chss/map/map.html
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Message 2:
Travis -
All of our scanning is done through mylar and I do not believe you will
notice any difference at all and, depending upon your scanner, the
encapsulation may be safer for the original artifact. One minor
disadvantage is that if the mylar should have a "kink" or scratch on it,
your scanner may pick that up and scan it as a streak across your map.
If you have a digital imaging group in the Library they should be able
to configure your scanner for optimization using the mylar.
David Cobb
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Message 3:
Greetings.
It is possible to scan encapsulated maps and have the scans turn out
fine. As another poster mentioned, some possible concerns include focus
and glare. The two immediate questions I would have are: what kind of
scanner are you planning on using? and how big are the maps? For
instance, on a flatbed scanner, as long as the entire item - film and
map - is flat on the scanner, the scan should work fine. If even a small
corner of the film is raised above the surface, you will probably end up
with glare and/or streak marks.
Interestingly enough, we scanned about 1500 encapsulated maps (out of
3500 total) as part of a 2-year project. You can see the maps at:
http://dallaslibrary.org/CTX/murphyandbolanz/home.html
(You will need the DjVu browser plugin (free) to view the maps).
When we were planning for this project and deciding whether to
encapsulate or scan first, we found that the polyester film (5 mil
thickness) acted as a filter of sorts, cutting down on the harsh
yellowing of the paper. The end result was we were able to read the
pencil notations on the maps much easier if the maps were scanned after
encapsulation. The Addition Book maps in this collection were scanned on
a MicroTek Artix Scan 2020. Most of the Block maps were scanned before
encapsulation, but some were scanned after encapsulation using a
planetary scanner, and the scans turned out just fine.
Good luck with your project.
Cheers,
Michael C. Miller
Special Collections Librarian
Dallas Public Library, Texas/Dallas History & Archives Division
1515 Young St.
Dallas TX 75201
214-670-1440
fax: 214-670-1437
[log in to unmask]
Visit us at http://dallaslibrary.org
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Message 4:
Travis;
There is nothing like a test...
I have found that for material that is not heavily used, bonding two
sides of the mylar capsule works and afte a scan, finish it off.
Patrick McGlamery
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Message 5:
It can cause glare and moire.
- bri
[log in to unmask]
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Message 6:
Hey Travis,
We scan using a Contex scanner whereby the sheet is fed into the front
of the scanner. The biggest problem is as the sheet reaches the end, any
air that might be in the mylar collects and wrecks that part of the
scan. I suppose if you were using a flatbed this would not be a problem.
Otherwise, in my opinion, the mylar itself doesn't detract significantly
from the image quality. However, with time and use, the mylar can become
cloudy from sliding on other surfaces which can lessen the scan
quality.
___________________________
Chris Mixon
Map Collection / GIS / Digital Resource Lab
Auburn University Libraries
231 Mell St.
Auburn University, AL 36849-5606
Phone: 334-844-1759
Fax: 334-844-1703
E-mail: [log in to unmask]
http://www.lib.auburn.edu
http://www.nacis.org
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Message 7:
It has been my experience that there is no problem with scanning of
encapsulated maps. The transparent sheet makes no effect on the quality
of the scan, whether using a flatbed scanner or a large format continuous
feed scanner. And with the latter type, the extra layers of the capsule
do not seem to pose a problem for the rollers as the map feeds through.
In fact, I think the mylar adds protection from mechanical damage that
could occur without it, especially where an edge or corner might be caught
as it feeds through.
I must indicate that my experience is limited to only a small number of
attempts at scanning of encapsulated items. A colleague with far greater
experience and knowledge using scanners says that the encapsulation
presents no problem for scanning, and my experience bears this out.
Ken
___________________________
Ken Grabach <[log in to unmask]>
Maps Librarian Phone: 513-529-1726
Miami University Libraries
Oxford, Ohio 45056 USA
XXXXXXXXXXXXXXXXXXXXXXEND END
|
