Transcription discs

Andrea Bowes <abowes [at] compusmart__ab__ca> writes

>The archives that I work with has several large collections of glass
>transcription discs from the 40's and 50's and they will be
>reformatting a selection of them soon.  I am unfamiliar with this
>archival record format and would like some further information
>before we proceed with this project.  In particular several discs
>have a white crystal formation over their surface.  What is the
>black layer of the disc made of?  What might the crystals be?
>Finally is there a safe way to remove them?

For information on transcription discs and a detailed analysis of
the white formation on the surface of some discs, see Christopher
Ann Paton's article "A Review and Discussion of Selected Acetate
Disc Cleaning Methods: Anecdotal, Experimental and Investigative
Findings" in the ARSC (Association of Recorded Sound Collections)
Journal XXVIII no 1 (1997): 1-23. According to her article the black
lacquer is either nitrocellulose or cellulose acetate. The white
greasy powder is mostly ricinoleic acid, the by-product of the
deterioration of the castor oil plasticizer used in some brands of
discs. The discs can be cleaned with a 1% solution of ammonium
carbonate, or Kodak Lens Cleaner.

David Seubert
Curator of Performing Arts Collections
University of California, Santa Barbara
David Seubert, Curator of Performing Arts Collections
Davidson Library Special Collections
University of California at Santa Barbara
Santa Barbara, CA 93106-805-893-5444

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                  Conservation DistList Instance 12:49
                Distributed: Wednesday, December 2, 1998
                       Message Id: cdl-12-49-004
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