When this project began, the Systems Integrations Group, (SIG), was the contractor employed by the Library of Congress to digitize this collection. Under this contract, the Drake collection was digitized in grayscale at 300 dots per inch (dpi) on a PhaseI and Pulnix camera. Select pages were digitized in color including pages with color on them and in some cases, handwritten items. Generally, bindings and blank pages were not captured. Upon completion of this contract and approximately midway through digitization, the Digital Scan Center of the Library of Congress digitized the remainder of the collection. At this point, the digitization specifications were altered to digitize the remainder of the collection in accordance with new standards set by the Rare Book and Special Collection Division. These new standards included scanning the item in entirety, including the cover, spine and the blank pages. In addition, all pages were digitized in color at 300 dpi with a Phase One FX, 4x5 format, TTI copy stand, using Linhof and John Reiser cradles or a Digibook High-Production Scanner.
The maps and views were digitized by the Map and Geography Division on a large-format (24 x 36 inches) flatbed scanner using a RGB (red-green-blue) 24-bit CCD color sensor (16.8 million colors). The scanner was a JumboScan from Lumiere Technology. The enhanced TIFF files were compressed, using a wavelet-based image compressing software called Multi-Resolution Seamless Image Database, or MrSID. This software integrates multiple resolutions of an image into a single file which enables Internet users with a standard browser to zoom in, getting more and more detail. Although MrSID is a "lossy" compressor, the images were compressed at a ratio of 22:1 without experiencing any loss of information.
TIFFs are stored in a master directory on the Library's RS5 servers. JPEGs and GIFS were derived from the TIFFs to make page-turners and bibliographic thumbnails with the use of Alchemy scripts. The JPGs were created at 400 pixels using image alchemy with a default quality ranking factor of 32. The GIFs were created at 150 pixels using image alchemy. The derivatives are stored on the service section of RS5, thus making retrieval faster.
Data and Text
The Hans P. Kraus Sir Francis Drake Catalog was text encoded in SGML format and was then converted into XML.
Descriptive data was populated into an Access database where the book portion of the collection was treated as MARC records and all other items in the collection were treated as Non-MARC records.