Building the Digital Collection

In addition to linking to hundreds of digitized items throughout the American Memory and other Library of Congress digital collections, the initial release of the American Women gateway site includes a small number of documents selected as a sample of the wide variety of women's history resources available in the Library. The selection of 36 items includes 14 books, pamphlets, and periodicals (or portions thereof); 13 pieces of sheet music; 2 atlases; 6 manuscripts; and 1 sound recording. The site also includes more than 250 digital images used to produce the illustrations in the publication American Women: A Library of Congress Guide for the Study of Women's History and Culture in the United States (Washington: Library of Congress, 2001). The original materials come from the General Collections of the Library of Congress, from the Law Library of Congress, and from the Geography and Map Division; Manuscript Division; Motion Picture, Broadcasting and Recorded Sound Division; Rare Book and Special Collections Division; African and Middle Eastern Division; Music Division; and Prints and Photographs Division.

Printed Matter, Manuscripts, and Sheet Music

Most of the images are grayscale. If an item was printed in multiple colors, or the color of the paper was significant, it was scanned in color.

Each master TIFF (Tagged Image File Format) image, or archival TIFF file, was produced by scanning the item at a resolution of 300 dpi (dots perinch).

Following scanning, the TIFF files were used as a basis for the creation of JPEG (Joint Photographic Experts Group) and/or TIFF reference images, adhering to practices previously established in presenting each respective format in American Memory. Image Alchemy software was used to create files for use in the Page Image Viewer.

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Illustrations

Many of the illustrations used in the American Women gateway were originally scanned by G&S Typesetters of Austin, Texas, for use in the published guide American Women: A Library of Congress Guide for the Study of Women's History and Culture in the United States. The images were scanned from black-and-white photographic prints or color transparencies of the originals. In some cases, where the Prints and Photographs Division already had a digital image made from the original item or a copy negative or transparency through it ongoing scanning programs, that image is used in the place of the typesetter's scan.

Maps and Atlases

Two items, A series of maps to Willard's History of the United States, or, Republic of America. Designed for schools and private libraries and Caldwell's Illustrated historical combination atlas of Clarion County, Pennsylvania, were scanned onsite by the Information Technology Services Digital Scan Center using a Power Phase FX overhead satellite camera. They were scanned in color at a resolution of 300 dpi.

Maps used as illustrations were scanned from black-and-white photographic prints or color transparencies by G&S Typesetters of Austin, Texas, for use in the printed guide American Women: A Library of Congress Guide for the Study of Women's History and Culture in the United States.

In the case of both the atlases and the maps, the TIFF files are 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 visual loss of information.

The final step is the use of Image Alchemy software to create a small GIF (Graphic Interchange Format) file for use as the initial thumbnail display of the item along with the bibliographic information.

Sound Recordings

The recording in this collection is represented by WaveForm (.wav), MPEG 2, Layer 3 (.mp3), and RealAudio G2 (.rm) versions. The Wave files were created from the original cassette or digital audio tape recordings at a sampling rate of 22,050 Hz per second, 16-bit word length, and a single (mono) channel. The RealAudio G2 files were derived from the Wave files through digital processing and were created for users who have at least a 14.4 modem (8-bit). The MP3 files were derived from the Wave files in a batch-conversion process using the MP3 plug-in of Sonic Foundry's SoundForge software.