Digital Imaging for Preservation
Digital imaging technology is a tool with many possible applications. By looking at this new technology critically, we can invest time and money wisely in converting library materials to digital image and ensure that it is a good investment on behalf of our patrons, both present and future.
"Acquiring" imaging technology to solve a particular problem is not the same as "adopting" it as a preservation option. Acquiring imaging technology to improve access to information, for example, is now almost as simple as choosing a combination of available features on a computer to meet immediate needs. In this regard, it is simply a tool. Adopting the technology, on the other hand, requires an institutional commitment of integrating imaging into our procedures and processes, and significant leadership in developing appropriate definitions and standards of quality.
To adopt digital imaging into preservation, consider the following update on a preservation principle: The fundamental goal of digital preservation is to preserve continuing access to digital data for as long as that data has value. As with traditional preservation service, this carries commitments. One is providing for continuing system functionality.
Today's optical media will far outlast the system's capability to retrieve and interpret the data stored on them. Working with manufacturers and within our institution to upgrade the system we acquire will maintain functionality of the system and its data. In practice this means adopting open architecture, non-proprietary systems, and utilizing systems which can read and convert information written by older generations of technology. This will limit storage media deterioration. The heart of system functionality is reliable retrieval of data. Before data error rates become unacceptable or even fatal, it is necessary to migrate digital data and the accompanying index information to newer generations of systems. Simply refreshing data by copying to new disks is not an acceptable long-term solution when imaging systems themselves become obsolete in three to five years.
Another commitment is to maximize the quality of digitized data. The image market has transformed one of the fundamental goals of preservation -- to maintain the highest possible quality over time -- to one of finding the minimal level of quality acceptable to system users. By maximizing the amount of data captured in the digital conversion process, documenting image enhancement techniques to preserve the integrity of the image files, and adopting file-compression routines that do not result in loss of data during telecommunication, we can improve the quality of digitized data.
A third commitment is to the structural integrity of the original information sources which have been converted. Digital images are dumb. They can be located only with the aid of a complex index. Without indexing, digitally converted library materials are simply random collections of files, stored and labeled in systems unintelligible to most users. Database management helps guarantee that the structural components of the original sources (indexes, chapter headings, finding aids, etc.) are built into imaging systems. Preserving the internal structures of books, serials, and primary source materials, however, is only half the battle. The other half is creating and then preserving the links between imaging, bibliographic, and other management-information systems.
These concerns offer some ideas to focus on as we integrate new systems into our institution. In terms of long term preservation and access, the fewer the variables the better. If, however, we are willing and able to make the necessary commitments to maintaining access for as long as source materials are valuable, digital technology offers amazing results.
Patricia Selinger is the Preservation Librarian for VCU Libraries.