VII. IMAGE, FULL-TEXT, AND CD-ROM FILES
Automated library systems are ceasing to be just bibliographic systems which point to information. Instead, they are becoming information systems which include images and full-text. At some time in the future, they may also contain multimedia-a combination of audio, video, and data.
Imaging in libraries is still in its infancy, but an increasing number of libraries are anticipating the addition of imaging capability to their automated library systems. Academic libraries are interested in storing and retrieving images of course reserve readings, especially journal articles; libraries of all types hope to protect fragile manuscripts and photographs by limiting the handling of the originals; and libraries with many locations anticipate offering equal access to unique materials to users regardless of where they are.
One of the major problems in imaging is that standards are still lacking. Only three major standards have been adopted. The rest are de facto standards which have yet to be adopted by national or international standards organizations. Nevertheless, libraries interested in imaging should specify adherence to de facto standards when specifying imaging.
Full-text files are increasingly being mounted on automated library systems and an increasing number of them are being configured as Web servers to facilitate access from Web browsers. Alternately, many libraries are participating in the creation of community, campus, or corporate Web pages on shared Web servers.
Electronic publications on CD-ROM now number in the thousands. Libraries are installing CD-ROM servers with towers accommodating a number of CD-ROM disk drives and are seeking to interface the servers with the automated library systems.
Libraries are also increasingly interfacing automated library systems with CD-ROM servers and towers. This requires that the CD-ROM drives and CD-ROM products conform to a standard.
The following standards and de facto standards are discussed in this chapter:
GIF Graphics Interchange Format
TIFF Tagged Image File Format
ISO/IEC 10918-1 Digital Compression and Coding of
Continuous-Tone Still Images (JPEG-Joint
Photographic Experts Group)
MPEG Motion Picture Experts Group
ISO 8879 Standard Generalized Markup Language
HTML HyperText Markup Language
ISO 12083 Electronic Manuscript Preparation and Markup
ISO 9660 Volume & File Structure of CD-ROM for
GIF. Graphics Interchange Format
GIF is a de facto standard which supports hardware-independent, online transmission of graphic image data. It is the most compact format for compressing images and is used to create "thumbnail" images that facilitate identification rather than study. Maximum compression to shorten image retrieval is the goal rather than quality. Compression is critical because an image of a single black-and-white image stored at a resolution of 300 dpi (dots per inch) takes up to 75 seconds to transmit at 9600 bps (bits per second)--the speed at which most installed systems currently operate. By using compression, the data transfer rate can be increased severalfold.
Color control is not as good with GIF as with JPEG. It is possible to convert GIF files to JPEG without loss of information, but …