Master WAVE (.wav) files were created at a sampling rate of 96,000 samples per second, 24-bit word length, and a dual (stereo) channel. The master files, due to their large size, are not included in the Web presentation but may be accessed in the American Folklife Center's Reading Room.
Three derivative copies of each master file are included in the online presentation. They include WAVE files created at a sampling rate of 44,100 samples per second and 16-bit word length as well as MP3 and RealAudio files created at a constant bit rate of 256 kilobits per second and a sampling rate of 44,100 samples per second.
Photographs and drawings were scanned on site at the Library of Congress Information Technology Services (ITS) scan lab using overhead digital cameras with Phase I software and were post-processed using Adobe Photoshop software. Images were scanned in either grayscale or color mode, depending upon the original, at 300 ppi and saved in the uncompressed TIFF file format. Three service images were also created: a compressed reference image in the JPEG format, averaging 1,024 pixels on the long side of the image with a compression rate of 8:1; a high-resolution compressed display image in the JPEG format, averaging 640 pixels on the long side of the image with a compression rate of 15:1; and a thumbnail GIF image averaging 150 pixels on the long side of the image.
Encoding the Manuscripts
Lyrics of the recorded songs were transcribed and converted to machine-readable form and were encoded with Standard Generalized Markup Language (SGML), according to the American Memory Document Type Definition (DTD). This DTD is a markup scheme that conforms to the guidelines of the Text Encoding Initiative (TEI), the work of a consortium of scholarly institutions. The texts of the transcripts have been translated to HTML for indexing and viewing on the World Wide Web.