Specifications
ALICE Digital Library of
Appalachia
File Specifications
DRAFT 0702
Good digitization practice directs
libraries to scan analog materials at the highest resolution
possible for archival purposes. The
archival copies will in most cases be large files unsuitable
for delivery over the Internet in our current
telecommunications environment. However,
high quality files may be used for in-house consultation; for
the production of print materials; and for future purposes yet
to be defined. It is likely that
compression technology will improve in the near future, and
these files may eventually be used for network delivery as
well. To reduce handling and protect
fragile original materials, the recommendation is that
libraries scan once and then produce derivative files from
this high-resolution archival file.
Individual libraries/archives make local decisions
on archival files. See guidelines from
Library of Congress and Research Libraries Group/Digital
Library Federation for recommended practices.
Initial decisions for scanning
text
Decide on creating essentially an image
file or OCR (or both). This decision will
depend on whether the original format is important, and on how
much searchability the library wants to
provide.
Decide on how to handle blank pages will
they be scanned or skipped.
Specifications for scanning
text
For files retaining original format, scan
at 350 dpi grayscale for pages with text only, 400 dpi for
pages with significant images. For plain
text files, scanning may be done at 300 dpi.
Access file will be .pdf. Maximum
delivery file size is 4MB. Large documents should be broken
into separate files to assure reasonable delivery times.
Initial decisions for scanning
photographs
Decide whether to scan the whole image area
(with edges) or whether it should be cropped.
In general, photographs should be scanned in their
entirety, including edges, to provide users with an authentic
surrogate.
Decide whether to scan sepia-tone
photographs as color or black and white images.
Scanning them as color images will offer users a more
authentic surrogate, but it will also increase the file size.
Decide whether to scan the backs of
photographs as separate image files. Some
photos have significant identifying information on the
back. This may be entered in metadata, or
offered as a linked image.
Decide on whether to provide users with a
raw image, an enhanced image, or both. In
addition to cropping, enhancements may include adjustments to
color, brightness and contrast; image cleaning (removing
scratches and stains); and reformatting from color to
b&w.
Specifications for
Black & White Photographs.
Scan at 600 dpi, 8 bit grayscale
Resize image to 640 x 480 pixels
Save in JPEG file format, Medium
(6-7)quality
[In Photoshop, use Save for Web, JPEG
Medium settings]
[In ImageReady, use Save Optimize]
Specifications for Color
Photographs.
Scan at 600 dpi, 24 bit
color
Resize image to 640x480
pixels
Save in JPEG file format, High
(6-7) quality
[In Photoshop, use Save for Web, JPEG
Medium settings]
[In ImageReady, use Save Optimize]
Specification
for Drawings, Maps, other illustrations
Scan at 300 dpi, 24 bit
color
Resize image to 640x480
pixels
Save in JPEG file format,
Medium (6-7) quality
[In Photoshop, use Save for Web, JPEG
Medium settings]
[In ImageReady, use Save Optimize]
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