Historical Collections for the National Digital Library:
Lessons and Challenges at the Library of Congress

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Footnotes & References

  1. Many aspects of the Optical Disk Pilot Project are described by Helena Zinkham and Marcy Flynn in The MARC Format and Electronic Reference Images: Experiences from the Library of Congress Prints and Photographs Division, Visual Resources, XI (1995): 47-70. The article demonstrates the strong links between the Optical Disk Pilot Project, the American Memory project, and the development of the One-Box image catalog used in the Prints & Photographs reading room.

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  2. One exception to the general policy of contracting out digitization operations is in the Geography & Maps Division, where a large flat-bed scanner donated by Tangent Engineering has recently been installed. This equipment is part of a more extensive facility supporting the division's Center for Geographic Information.

    Another is the in-house use of a Pro/3000 Digital Imaging System donated by IBM. This overhead digital camera, a research project rather than an IBM product, is currently being used to capture pictorial materials associated with the Federal Theatre Project (started in 1935 by the Works Progress Administration to provide jobs for theater professionals during the depression). The conversion of this collection is being supported by IBM's Research Division as a test of the digital camera and of the integration of image management software into the library's overall technological framework.

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  3. The use of a high-quality photographic intermediate when digitizing visual materials is recommended by Kevin Donovan of Luna Imaging, Inc. in The Anatomy of an Imaging Project: A Primer for Museums, Libraries, Archives and other Visual Collections, Spectra: Journal of the Museum Computer Network 23(2) (Winter 1995/1996): 19-22. Among the benefits is the ability to re-digitize the analog reproduction in the future when technology improves. Digital versions that can match the visual information in a high-quality photographic reproduction would require files so large as to be of little practical use for with today's display technology and network bandwidth.

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  4. Each collection is given a unique name of up to 8 characters. The Digital Conversion Team has found it useful to limit names to 8 characters for compatibility with DOS filenaming limitations. Within a collection an item has a unique name, often limited to fewer than 8 characters because an item may comprise several files.

    For example, most images have three digital versions. The image with "logical" name "detroit/4a32371" is represented by a thumbnail (4a32371t.gif), a compressed "reference" version for routine access (4a32371r.jpg), and an uncompressed version (4a32371u.tif).

    A pamphlet or book (say "nawsa/n7111") has a pair of SGML files (n7111.sgm and n7111.ent) that represent the document. Images for each page are numbered in sequence (n7111001.tif, n7111002.tif, etc.). Images for illustrations and tables are numbered in a separate sequence.

    The logical name for an item is used in bibliographic records (in MARC field 856, subfields $d and $f) and as a link from SGML documents (for which subsidiary "entity" files provide additional information about the type and location of the linked items). Currently, files for each collection are stored in a Unix directory structure; the logical name is parsed and a "locator table" is used during retrieval to derive full pathnames (URLs) for an item and its component files.

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  5. Research Libraries Group Digital Image Access Project, proceedings from a symposium held March 31 and April 1, 1995 in Palo Alto California, edited by Patricia A. McClung [RLG: Mountain View, CA]. This report summarizes experiences from an eighteen-month project in which nine RLG member institutions (including the Library of Congress Prints & Photographs Division) provided images and catalog records to build a prototype unified database. The other institutions were the Amon Carter Museum, Columbia University, Duke University, the Getty Center for the History of Art and the Humanities, the Frances Loeb Library of the Harvard University Graduate School of design, the New York Public Library, Northwestern University, and the University of California at Berkeley. [The links to Columbia and Berkeley point to online versions of two papers from the project report.]

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URLs for links to other resources

These URLs are listed in order of "appearance" in the article.

  1. American Memory home page for Historical collections from the National Digital Library Program at http://lcweb2.loc.gov/ammem/ammemhome.html
  2. Mission and Strategic Priorities of the Library of Congress at http://lcweb.loc.gov/ndl/mission.html
  3. Machine-Readable Cataloging (MARC) standard. Maintenance agency page from Library of Congress at http://lcweb.loc.gov/marc/
  4. Z39.50 standard for information search and retrieval over networks. Information and maintenance agency page from Library Of Congress at http://lcweb.loc.gov/z3950/agency/
  5. THOMAS, Library of Congress service providing access to current legislative information at http://thomas.loc.gov/
  6. CORDS, experimental prototype for copyright registration and deposit of digital items, described at http://lcweb.loc.gov/copyright/cords.html
  7. Final Report of the American Memory User Evaluation at http://lcweb2.loc.gov/ammem/usereval.html
  8. American Memory white papers at http://lcweb2.loc.gov/ammem/techpapr.html
  9. NDLP Learning Page at http://lcweb2.loc.gov/ammem/ndlpedu/
  10. Text Encoding Initiative Guidelines at http://etext.virginia.edu/TEI.html
  11. Encoded Archival Description (EAD), described at http://sunsite.berkeley.edu/FindingAids/#ead
  12. The Research Libraries Group announcement of the final report from its Digital Image Access Project, at http://www-rlg.stanford.edu/pr/9509diap.html
  13. Digital Image Collections: Cataloging Data Model and Network Access by Stephen Paul Davis of Columbia University at http://www.columbia.edu/cu/libraries/indiv/avery/diap.html
  14. Access to Digital Representations of Archival Materials: The Berkeley Finding Aid Project by Daniel V. Pitti of the University of California, Berkeley at http://sunsite.berkeley.edu/FindingAids/EAD/diap.html
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