Building the Digital Collection

The Bancroft Library received an award in the 2001 The Library Services and Technology Act (LSTA) through the California State Library to support the digitization of materials related to The 1906 San Francisco Earthquake and Fire. Additional partners in this project were the California Historical Society, Stanford University Libraries, The Huntington Library, the California State Library, and the Society of California Pioneers. The materials proposed for digitization reflected a broad range of formats and topics illustrating the history of the San Francisco 1906 Earthquake and Fire.

Important aspects of building this digital collection are described below.

Selecting the Source Materials

The 1906 San Francisco Earthquake and Fire is a virtual archive of materials selected from a number of diverse collections at The University of California at Berkeley's Bancroft Library and collections held by the California Historical Society, Stanford University Libraries, The Huntington Library, the California State Library, and the Society of California Pioneers.

Intellectual Access to the Collection

The UC Berkeley Library's Project Control Database was designed as a reusable tool which curators could use to build digitized collections of diverse archival materials such as photographs, drawings, letters, manuscripts, and books. It has been used in numerous digitization projects including, the NEH-funded Making of America II, projects funded by LSTA to digitize cased photographs, and the Museums in the Online Archive of California (MOAC) project, funded by IMLS. The MOAC project has been described in an April 2002 article in FirstMonday by Robin L. Chandler. The database is also in use for the California Cultures project, funded through the Library of Congress.

The project control database manages the process of creating digital objects; creating intellectual description and access information (the database is designed to accommodate all major descriptive standards currently in use in digital projects) and correlating it with text and image files; provides necessary structural metadata; and records image capture data. Information recorded includes fields for: Identification of Item (Collection Name, Call Number, Series name/Sub-collection number, Shelving location, Item identification - (Volume, Container, Folder, Item numbers), Caption); Digital File (Format, Resolution and Dimensions, File location). EAD container listings of finding aids are also automatically generated from information in the database at the end of the process using perl scripts. The database also automatically binds multi-part digital objects together into XML encoded (as Metadata Encoding and Transmission Standard - METS) objects. It tracks all of the administrative metadata for the images, storing important information as to how the archival images and their derivatives were processed, when, and with what methods. The database accommodates different image processing work flows (flatbed scanner, multipage scanner, and digital camera) and the workflow for reformatting and marking up electronic texts. This database is currently the standard tool in OAC digital projects.

Project staff entered a brief descriptive record for each object in the project control databases. Descriptive and administrative metadata was keyed in by staff into separate project control databases set up for each of the partner institutions. The descriptions present in the finding aids follow rules set forth in Anglo-American Cataloging Rules, 2nd edition (AACR2) and in some cases was taken directly from the MARC bibliographic records in some of the institutionís online public access systems. As necessary, local data conventions and guidelines were developed to aid in the consistency of data entry across institutions.

The database is hierarchical, so that entries could be made for collections, with all related item entries made under their collection record. Records contained identifying call numbers, titles, project batch numbers used for routing and tracking material for digitization, physical descriptions, subject headings and other cataloging information including contextual notes.

Imaging

The UC Berkeley's Digital Imaging Lab (DIL) served as a service bureau offering digital image capture service. Following other CDL collaborative imaging projects, DIL and project partners met the standards described in the CDL's Digital Image Collections Standards. The image production process used by DIL in this project was originally designed for the California Heritage Digital Image Access Project (funded by NEH) and has been used to produce the images and detailed descriptive information for a number of projects including the project s mentioned above and the LSTA-funded Japanese American Relocation Digital Archive (JARDA) project.

DIL performed digital image capture using an Agfa Arcus II flatbed scanner and a PhaseOne Powerphase digital camera. The PhaseOne Powerphase digital camera scanning back was used with a Hasselblad with 120mm Makro-Planar CF lens, mounted on a copystand, with Kaiser daylight fluorescent illumination. The Agfa Arcus II flatbed scanner is used primarily for loose (unmounted) originals; while originals mounted in bound volumes, framed originals, and originals larger than the platen of the scanner (8 x 13 inches) are captured with the PhaseOne Powerphase digital camera scanning back on a Hasselblad with 120mm Makro-Planar CF lens, mounted on a copystand, with Kaiser daylight fluorescent illumination.

As part of the initial capture, images were balanced for brightness, contrast, and color, using the proprietary software supplied by the equipment manufacturers. A compact target including a grayscale, centimeter and color patches was included for reference with each scan. Typical capture resolution is between 300 and 600 dpi, with the 600 dpi level utilized whenever practical. The digital master files are archived onto writeable cd media (CD-ROM) as 24-bit RGB TIFF files. Derivative (viewing) files were created from the digital masters in batch mode using Photoshop and Debabelizer software to produce JPEG (JFIF) and GIF format files at the reduced resolution levels appropriate for viewing. Quality review of work was done at a number of points in each production workflow, first at the point of capture on flatbed scanner and digital camera (since each is a 'one off' operation) and finally just before web presentation when both images and text were viewed with a browser to confirm their accessibility.

Photograph citation:

San Francisco — one year after. The beginning of new and greater San Francisco showing a large amount of reconstruction in the heart of the city. Millions of dollars spent to make San Francisco one of the finest cities in the world. [Detail]
Charles Weidner
BANC PIC 19xx.169:074—AX
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