Background: Analog audio recordings of cylinders and phonograph disks are at risk for loss as they deteriorate, exfoliate, or break. In addition, standard playback techniques using stylus or other tactile systems can in themselves cause change. The Library of Congress, in collaboration with the Lawrence Berkeley National Laboratories, has pursued the develop imaging systems to use 2 and 3 dimensional scanning techniques to capture sound from laterally and vertically grooved analog sound recordings.
In collaboration with Lawrence Berkeley National Laboratory, the IRENE project developed a non-contact, two-dimensional imaging technique to acquire digital images of the lateral groove movement of audio disc recordings. Software has been designed to analyze these images and produce standard audio file output for playback and archiving. The initial phase in a larger research initiative to apply non-contact digital imaging technologies to preservation and access for grooved audio media has focused on high-throughput digitization of a variety of disc media. The device (called the IRENE machine) has successfully captured the content of laterally grooved disks as well as phonautograms, the first known recordings of sound.
Three-dimensional confocal scanning of sound recordings produces a topographical map of the media surfaces. Current advancements in confocal probe technologies have led to scan times that begin to rival the two-dimensional imaging speed achieved in the IRENE project. The three-dimensional technique provides much more information than two-dimensional imaging when used on laterally cut discs, and allows examination of historically significant vertically cut media such as fragile wax cylinders.
Contributing Study: IRENE project for two-dimensional scanning of laterally grooved analog sound recordings
Project Description: Research will look for improvements in efficiency and quality of IRENE imaging through the application of three-dimensional confocal imaging for high-quality digital scanning of vertical grooves in grooved sound recordings such as wax cylinders, LPs, and other media formats. The Preservation Research and Testing Division will test the new technology prior to its deployment to the National Audiovisual Conservation Center in Culpeper, Virginia. Reconstruction of broken and damaged media will become a focus in the coming research cycle.
Outcomes/Findings:
- Can three-dimensional confocal scanning improve efficiency in scanning sound recordings
- Can three-dimensional confocal scanning improve provide increased fidelity in resulting digital wave files
- Can three-dimensional confocal scanning support the reconstruction of broken and damaged sound recordings
Support:
- Institute of Museum and Library Services
- Lawrence Berkeley National Laboratories
- Library of Congress Library Services
Acknowledgements: Lawrence Berkeley National Laboratories
Update and Images:
- September 2007: IMLS funds the development of the 3-D scanner
