National Preservation Research Agenda for the Human Record: Scientific Research Focuses of the Library of Congress Preservation Directorate
The Preservation Directorate at the Library of Congress uses a broad spectrum of traditional and cutting edge strategies to help assure long-term, uninterrupted access to the content of the Library's collections. Strategies are based on practical experience with millions of items that represent nearly every format used to record our cultures, creativity, and information, and they are based on high-quality scientific research.
The Preservation Directorate includes one of only a few scientific research laboratories dedicated to the characterization, understanding, and treatment of library and archival materials. For 40 years the Library’s scientists and conservators have worked to inform the research of other libraries, archives, and museums, improving our ability to extend the use-life of collections effectively, efficiently, and economically. In this, the Library’s research contributes to preservation decisions by collections stewards around the world as well as in the Library itself. This is evidenced in the Library’s convening role for the 2008 Summit of Research Scientists in Preservation and the 2009 Summit on Research/Technology Transfer, supported by funding from the Samuel H. Kress Foundation, the National Center for Preservation Technology and Training, and the American Institute for Conservation, and by Library contributions to research supported by the Institute of Library and Museum Services and the National Endowment for the Humanities. These efforts have validated the Library’s six focus areas for scientific research, described below, as among the most pressing for national and international preservation research. Details of ongoing symposia can be seen through links on the Topics in Preservation Science (TOPS) website. The Preservation Research and Testing Division will be hosting a Summit of Research Scientists in 2015 to share current advances in research and review collection issues and challenges identified at the first Summit.
Environmental Studies: Preservation research over the past decades has demonstrated that temperature, light, moisture, and chemicals in the vicinity of collections (including specific pollutants) can start or speed chemical reactions that cause both visible and microscopic damage. While many of the related phenomena and degradation mechanisms are well researched, not all are well understood, and many of the detailed processes of deterioration in the wide range of materials that comprise collections commonly found in libraries or archives. The Preservation Directorate’s environmental research focuses on understanding environmental causes of damage; finding ways to predict deterioration related to environmental conditions; and finding efficient, cost-effective, and responsible methods of controlling library environments. Library of Congress research led to the important finding that temperature and moisture combine to drive some chemical damage at rates we can model confidently, leading to recommendations for storage conditions to slow deterioration.
Preservation of Traditional Materials: Understanding the characteristics of deterioration in library collections is as important as knowing the contributions of environment to decay. The Preservation Directorate’s research looks in detail at the characteristics of materials found in library collections—recorded information and its carriers in all their many forms—and how they change over time. This research also looks at the results of conservation treatments and preservation strategies to slow damage to those materials and their combinations. For example, Library of Congress research helped develop mass deacidification to address acid-related paper damage. Answers to questions about deterioration of “pre-digital” collections remain critical, because in the transition to more fully digital service, libraries will be challenged to prioritize, treat, and integrate legacy collection workflows with continuing digital developments. Through the period of their copyright protection, information sources in both traditional and digital formats will be needed to support education and research.
Preservation of Audio-Visual Materials: The recognition that moving images and recorded sound in their various formats, and video and computer tapes and discs are highly vulnerable to damage and loss has come to our awareness relatively late. This is in part because writing, drawing, and associated materials have been with us for a longer period of time, and in part because the rapid deterioration of acid-prone papers produced since the mid-19th century generated pressing widespread concerns late in the mid-20th century. Modern media are created from a range of composite materials, and were a reaction to the ability for mass production of sound and audio recordings that could be easily mass manufactured for wide distribution. Manufactures were not concerned about the longevity of these materials. Preserving audio-visual materials has often taken the form of copying them to newer formats as those become available. This copying option, whatever technology is used, depends on two factors. It needs originals in good, stable condition, and it needs access to machines that can read and reformat the originals. Unfortunately both factors are hard to guarantee in the long term. In the short term, the risk of losing major A-V collections has become as urgent as the earlier acid paper threat. Preservation Directorate research has helped develop machinery to read and digitally reproduce many damaged sound recordings without additional damage. Other Preservation Directorate research has focused on understanding and recreating “sticky shed,” which makes many magnetic tapes unreadable.
Preservation of Digital Materials: Digital technology has changed our very paradigms of creating, storing, and transmitting images, sounds, and ideas in ways most people could not imagine even 50 years ago, and we have only begun to tap its potential. Unfortunately collections based on this technology—the devices that store it and the ones that allow us to use it—are the most vulnerable to the most rapid loss. The physical formats (think of punch cards vs. paper or magnetic tapes, vs. 8-, 5¼-, 3½ -inch floppy discs, vs. CDs and DVDs) change fast, and manufacturers use different materials and processes. Data storage formats change fast (think of Betamax to VHS to Blu-ray). The machines that play them change fast and the conventions by which we organize access to them (“meta-data”) have yet to develop full consensus. Libraries are still experimenting with strategies to preserve long-term access to digital information, which for libraries means 100 years and more. Current Preservation Directorate research focuses on understanding the physical nature of storage media and their deterioration, which will be essential to copying and reformatting collections whose original reading machinery no longer exists. The Preservation Directorate is also studying deterioration and longevity of digital discs.
Time-Based Media: The Library of Congress includes many examples of time-based media. Examples include film, audio, video, and computer-based works, many of which are used in performance or multi-media installations. Preserving these works can be especially challenging since they depend on playback technologies and include time as a dimension. Unintended deterioration and intentional migration to new formats can cause inappropriate or unacceptable changes that prevent access to the full content of the work. To address these challenges, some Preservation Directorate research targets these media. This research has helped develop scanning technology for grooved audio recordings; accurately characterized video and audio magnetic tape deterioration; and identified characteristics of CD/DVD longevity. Upcoming studies will help develop 3-D confocal imaging for vertically-grooved sound recordings (e.g. wax cylinders); compare fidelity of audio tape sound before and after baking to permit reformatting; identify chemical markers in magnetic media afflicted with sticky-shed; characterize morphological changes correlated with differing treatments and environmental conditions for films and magnetic media; and determine block error rates and correlate BLER to physical damage in naturally-aged digital disks. Mass production of sound and audio-based media allowed for greater distribution of these recordings, but manufacturers were not focused on the longevity of the substrate materials. One of the main challenges with time-based media is the degradation not only of the materials composites, but the digital preservation of the content contained on these modern materials. The Library has been developing Digital Preservation Guidelines and recommendations for levels of digital preservation, to enable best preservation and capture of content prior to any loss.
Technology Transfer: Digital and advanced technologies have advanced our ability to store and analyze large quantities of data and information. A number of science, technology and engineering and math (STEM) disciplines are developing increasingly sophisticated instruments and software to better analyze materials. One of the critical components in the Preservation Directorate is the focus on non-invasive analytical instrumentation, ensuring long-term preservation of library materials without the need for sampling. Preservation scientists have adopted and adapted these technologies to study a wide range of materials at ever-decreasing scales and greatly improving the capacity for materials analysis, assessment of degradation mechanisms and development of advanced instrumentation for non-invasive assessment of collection items. This research supports all categories of the Preservation Directorate scientific studies, but it also supports research into the history, characterization, and authentication of important individual items and collections. For example, the Preservation Directorate has used advanced digital imaging to characterize and date inscriptions on the 1507 Waldseemüller Map, the first known to use the word “America,” and to study original erasures and changes in a draft of the Declaration of Independence to better understand its creation. New applications of research methods to library collections can transfer back to enhance research in other contexts. The Preservation Directorate has recently developed collaborative relationships with research labs in non-cultural federal agencies to benefit both sides of this equation.
Scientific Sample Reference Collections: One of the great challenges in understanding library materials and their deterioration is the ability to repeat and replicate results across experiments, laboratories, and collections in different institutions. Many older storage, handling, and repair histories were undocumented, and it is often impossible to know how or where even modern paper, blank CDs, photographic chemicals, or other materials were originally manufactured. Small variations can result in significant differences in the behavior of materials and their combinations over time, and unless well documented, results from analytical instruments can differ with their settings (“calibration”). These realities make it essential to have reference standards to improve scientists’ confidence in relating their findings to those of others. The Library has assembled a pre-eminent collection of materials for this purpose. In 2008-09 the Library created a new room to strengthen consistency and tracking of storage conditions for these samples, and the Preservation Directorate scientists began to create analytical profiles for them, documenting the instrument calibrations used. A digital library of these data plus original samples from the collections (CLASS-D), will be available to other laboratories to increase the reliability of preservation research data around the world. Representative sample collections include the Barrow Book Collection (for paper research) and the Forbes Pigment Collection (for inks, printing, drawing, and other media).
