Background: The Library of Congress has many examples of time-based media, particularly in MBRS and AFC collections. Examples include analog film, audio, and video as well as digital works, many of which are used in performance or multi-media installations.
Preserving these works can be especially challenging since they are depended on technology to be heard or viewed, and include duration as a dimension. Deterioration and data migration can cause inappropriate or unacceptable changes to the original content and timing of that content that prevent access to the full content of the work.
Consequently, LC has developed the following research programs targeting these issues:
- Imaging of Laterally and Vertically Grooved Analog Audio Recordings
- Magnetic Tape "Sticky Shed" Research: Characterization, Diagnosis, and Treatment
- CD ROM Longevity Research
- CD-R and DVD-R RW Longevity Research
- DVD ROM Longevity Research
Description of Project Proposals:
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.
Future studies will focus on:
- Developing a device to use non-contact 3-D confocal imaging of vertically grooved sound recordings such as fragile wax cylinders.
- Documenting fidelity of sound on audio tapes before and after baking to enable reformatting.
- Identifying chemical markers in magnetic media afflicted with sticky-shed using FTIR.
- Characterizing morphological changes in films and magnetic media following various treatments and in different environmental conditions, using E-SEM.
- Tracking naturally aged CD-ROMs, etc. to determine error rates (BLER) and correlate BLER to physical damage.