Digital Imaging Services for Harvard Libraries

When described by library catalog records or other discovery metadata, and distributed to users via the world wide web, digital images serve as ideal surrogates to improve access to library collections. To digitize, however, is not necessarily to preserve: no standards exist for preservation digitization. In our collections reformatting workflows, we have instituted the practices recognized by the research library community as "best" to produce sustainable images. These include: using well-supported formats for image masters; implementing quality control over systems, products, and processes; producing appropriate technical metadata; associating image objects with descriptive metadata records; and depositing images to a preservation repository.

Harvard College Library's Imaging Services department has skilled staff and a top-quality array of imaging devices capable of reproducing the wide variety of texts, artwork and objects found in the research collections of Harvard's libraries, museums, and archives.

Requests for collections reformatting services are individually evaluated based on the handling requirements of the source materials, project budget, and the intended near-term and envisioned long-term uses of the proposed digitized resources.

All digital images produced in support of collections reformatting projects are deposited to the Harvard Digital Repository Service (DRS), bundled with the administrative, technical, and preservation metadata required for long-term data management.

Workflows for collections digitization are optimized for two broad categories of library collections: general collections, and special collections.

General Collections

Books, serials, and pamphlets, carefully handled and safely secured in self-leveling book cradles, are scanned using overhead scanners. After scanning, digital page images are batch processed using a single tonal and color correction script for printed text and illustrations. Page images are processed further using layout analysis and optical character recognition software to produce digital reproductions that are easily navigable and support full text searching (see structural metadata).

The best candidate materials for our General Collections digitization workflow have the following characteristics:

• Bound volumes, must be less than 24" in the long dimension when fully opened
• Bound volumes, must be capable of being fully open (180 degrees) and pressed lightly against book cradle glass
• No loose pages -- pages remain connected to bindings
• Published after 1820

Note: Materials that are unbound, fragile, damaged, or published prior to 1820 remain candidates for digitization, but these items will need to be reviewed by IS staff prior to processing.

Sample items

• Pamphlet (http://nrs.harvard.edu/urn-3:FHCL:1085749)
• Book with simple structure (http://nrs.harvard.edu/urn-3:FHCL:895073)
• Book with complex structure (http://nrs.harvard.edu/urn-3:FHCL:890863)
• Serial (http://nrs.harvard.edu/urn-3:FMUS.ORC:959210)
• Serial (http://nrs.harvard.edu/urn-3:RAD.ARCH:844137)

Special Collections

Employing handling procedures developed in consultation with book, paper, and photograph conservators from the Weissman Preservation Center, rare and delicate materials are photographed and adjusted individually, or in batches, to match the color and tones of the original items. Images are edited using calibrated monitors within a controlled viewing environment complying with the ISO 3664:2000 standard, "Viewing conditions -- Graphic technology and photography".

Safe handling of the original items is always the highest priority. Originals may be photographed with or without overlayed glass or on a vacuum easel. Items larger than 42 inches in the long dimension may be photographed in sections, and in many cases may be stitched into a single image file prior to deposit to DRS.

Transmissive film-based originals (e.g., negatives, 35mm slides, large format color transparencies, glass plate negatives, lantern slides) may be scanned using a flatbed scanner or may be photographed on a light box.

Guidelines/Procedures

• Guidance for Digitizing Images (Weissman Preservation Center)
• Guidance for Digitizing Text (Weissman Preservation Center)