Standards

Contents: Digital Library Data Model; Specifications for Sharing Metadata With Us; Archival Scanning Guidelines; Advice on Digitization Projects; Technical Information on Digital Formats; Metadata: What Is It and Why Is It Important?; Related Links

Digital Library Data Model

The University Libraries' digital library program, for non-subscription based electronic content, emphasizes distributed content storage and centralized metadata aggregation. Care and maintenance of digital collections and content remains as much as possible in the hands of the creating unit or individual.

This model is based on the assumption that an individual digital collection site on the Internet will be discovered (and used) less frequently by itself than if the same site is linked and indexed in a well-planned, larger "aggregator" database. To maximize use of disparate and distributed digital collections across campus, the University of Minnesota Libraries Digital Collections Unit is building an aggregator that collects key descriptive information (metadata) about each object in distributed databases across campus. Such a gateway will be promoted as the digital content search engine for the entire campus, and will greatly enhance the odds of discovery of any object or database on campus. Once the resource is discovered through this metadata aggregator, users will be directed to its home site. The Libraries anticipate increased usage of each site that contributes/shares metadata to the aggregator, and will further expand potential audiences for digital collections by sharing metadata collections with other off-campus harvesters and Web search engines.

Specifications for Sharing Metadata With Us

In the first phase of this approach, the Libraries collected metadata aboout many distributed digital image collections on campus. This initiative was named IMAGES (Image Metadata Aggregation for Enhanced Searching). Recently, IMAGES has been mainstreamed into a larger search database of digital collections, including visual, textual, and other content. The search tool for all these digital collections and resources is located on the home page for the Libraries' Digital Collections Unit.

To promote metadata sharing on campus, the University Libraries have created a core set of data elements that is used to map and exchange common pieces of information about each discrete digital object. This metadata scheme is flexible and can be used as the basis for a digital collections database, or just as a convenient common "language" for expressing information about your digital content. For more information, please see the above link or contact Chuck Thomas, Digital Projects Coordinator for the University Libraries.

Archival scanning

The notion of "archival" scanning is a misnomer in most cases. Digital reproductions are just that: a reformating technology. It is rarely intended to replace the original item, except when that item would disintegrate on its own accord. Even so, a high-quality digital reproduction can help preserve the original by removing it from excessive handling or casual use. In such cases, scanning should strive to capture the essence of the item in terms of detail and color fidelity, as well as information about the original and its digital surrogate.

There are no accepted standards for "archival" scanning, although plenty of guidelines. Most guidelines are designed to practically capture the greatest amount of detail relevant to the image. Most high-resolution images are stored off-line because of their size (easily 50MB in the case of a 600 pixel per inch scan at 24-bit color) and the relatively low throughput of the Web.

The most underestimated expense of scanning is capturing information about the scan (metadata), as well as providing adequate descriptive information about the image. While most archives describe their holdings collection by collection, the process of putting images on the Web demands an item-by-item description. Archivists have an ethical requirement to explain individual images in the context of the collection in which they were found. With no established metadata requirements, and virtually no software to connect everything together, the descriptive process may turn out to be the most expensive part of a scanning project.

References about Scanning Guidelines

Library of Congress - Digital Formats for Content Reproductions

"Creating and Distributing High Resolution Cartographic Images" by David Yehling Allen, in RLG DigiNews

"Digital Imaging for Photographic Collections: Foundations for Technical Standards" by Franziska Frey ,in RLG DigiNews

Joint RLG and NPO Conference on Guidelines for Digital Imaging in RLG DigiNews

PIMA / IT10 Technical Committee on Electronic Still Picture Imaging

Preservation-Quality Scanning of Bound Volumes: Integration of the Picture Elements ISE Board with the Minolta PS-3000 Book Scanner by Lou Sharpe in RLG DigiNews

Advice on Digitization Projects

The following sites offer excellent general guidelines for digitization projects:

Moving Theory Into Practice
Scanning Photographic Collections
Visual Resource Image Quality
RLG Guidelines for Imaging
Digital Libraries Resources
Visual Arts Digital Resources

Technical Information on Digital Formats

The following sites offer specific recommended technical formats for different types of original information:

Digital Formats for Reproductions
Preserving Digital Information
Digitization Technical Standards
Other Archival Scanning Guidelines

Metadata: What Is It and Why Is It Important?

Metadata is an important part of any digital project, if you wish to make the project site discoverable and manageable. The following sites provide useful explanations of metadata concepts and implementation:

Dublin Core Metadata Initiative
Metadata for Digital Preservation
Metadata Crosswalks