The Cornell/Xerox Joint Study in Digital Preservation resulted in the
recording of 1,000 brittle books as 600-dpi digital images and the
production, on demand, of high-quality and archivally sound paper
replacements. The project, which was supported by the Commission on
Preservation and Access, also investigated some of the issues surrounding
scanning, storing, retrieving, and providing access to digital images in
a network environment.
Anne Kenney will focus on some of the issues surrounding direct scanning
as identified in the Cornell Xerox Project. Among those to be discussed
are: image versus text capture; indexing and access; image-capture
capabilities; a comparison to photocopy and microfilm; production and
cost analysis; storage formats, protocols, and standards; and the use of
this scanning technology for preservation purposes.
The 600-dpi digital images produced in the Cornell Xerox Project proved
highly acceptable for creating paper replacements of deteriorating
originals. The 1,000 scanned volumes provided an array of image-capture
challenges that are common to nineteenth-century printing techniques and
embrittled material, and that defy the use of text-conversion processes.
These challenges include diminished contrast between text and background,
fragile and deteriorated pages, uneven printing, elaborate type faces,
faint and bold text adjacency, handwritten text and annotations, nonRoman
languages, and a proliferation of illustrated material embedded in text.
The latter category included high-frequency and low-frequency halftones,
continuous tone photographs, intricate mathematical drawings, maps,
etchings, reverse-polarity drawings, and engravings.
The Xerox prototype scanning system provided a number of important
features for capturing this diverse material. Technicians used multiple
threshold settings, filters, line art and halftone definitions,
autosegmentation, windowing, and software-editing programs to optimize
image capture. At the same time, this project focused on production.
The goal was to make scanning as affordable and acceptable as
photocopying and microfilming for preservation reformatting. A
time-and-cost study conducted during the last three months of this
project confirmed the economic viability of digital scanning, and these
findings will be discussed here.
From the outset, the Cornell Xerox Project was predicated on the use of
nonproprietary standards and the use of common protocols when standards
did not exist. Digital files were created as TIFF images which were
compressed prior to storage using Group 4 CCITT compression. The Xerox
software is MS DOS based and utilizes off-the shelf programs such as
Microsoft Windows and Wang Image Wizard. The digital library is designed
to be hardware-independent and to provide interchangeability with other
institutions through network connections. Access to the digital files
themselves is two-tiered: Bibliographic records for the computer files
are created in RLIN and Cornell's local system and access into the actual
digital images comprising a book is provided through a document control
structure and a networked image file-server, both of which will be
described.
The presentation will conclude with a discussion of some of the issues
surrounding the use of this technology as a preservation tool (storage,
refreshing, backup).