Background: Analog audio recordings, such as cylinders, phonograph disks, and dictabelts, 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 development of imaging systems that use 2 and 3 dimensional scanning techniques to capture sound from laterally and vertically grooved analog sound recordings.
Contributing Study:
IRENE project for two-dimensional scanning of laterally grooved analog sound recordings:
Sound Reproduction R & D Home Page
Project Description: Prototype machines have been developed to scan laterally and vertically grooved sound recordings. These prototypes are being tested by the Preservation Research and Testing Division prior to deployment to the National Audiovisual Conservation Center (NAVCC) in Culpeper, Virginia. The devices have been used not only to successfully capture laterally grooved disks, but also phonautograms, dictabelts and other recording materials.
Outcomes/Findings:
- Scanning of lateral discs with 2D imaging requires 15-20 minutes for a 10 inch 78 rpm disc
- Scanning of vertical cylinders with 3D imaging requires 20-60 minutes for a 4 inch "Edison" style cylinder, depending upon required resolution
- Scanning of lateral discs with 3D imaging currently requires a few hours due to the higher resolution required on the steep groove walls
- Original scanned images are stored as digital files which can be accessed later for optional re-analysis. Extracted audio is stored as standard WAV files for playback. These digital files capture information that could not be otherwise accessed in the original media
- LC has launched 2D scanning of laterally grooved sound recordings into production mode at NAVCC
- A program is underway to study and refine 3D scanning for vertically-grooved sound recordings and lateral discs
- Institute of Museum and Library Services
- Lawrence Berkeley National Laboratories
- Library of Congress Library Services
- National Endowment for the Humanities
Acknowledgements: Lawrence Berkeley National Laboratories
Update and Images:
April 2010: Update on an LC Technology Transfer Project to Preserve Time-Based Media - Peter Alyea
September 2007: IMLS funds the development of the 3-D scanner
