3-D Confocal Imaging of Vertically Grooved Analog Audio Recordings - Research Projects - Preservation Science (Preservation, Library of Congress)

Oct 20, 2026

A fragile recording can be treated as a tiny landscape rather than played with a needle. According to the Library of Congress, three-dimensional confocal scanning maps the surface of grooved recordings, including cylinders and discs. That matters because conventional playback touches the groove, and the Library says contact can alter recordings already vulnerable to damage. Imaging offers a way to examine their shape without adding that particular risk. The Library describes a related two-dimensional system that photographs the sideways movement of grooves on discs; software analyzes those images to produce audio files. A three-dimensional map could capture a different feature: the changing depth of a vertically grooved recording. The prov