CD corrosion

Karen C. Driessen (karend@selway.umt.edu)
Thu, 19 Mar 1998 17:35:14 -0700

Sorry for the duplication to media-l subscribers.

Because I have had a couple more inquiries from the list I will share the
rest of the info that I have with all. KD

Information is the following:

"A substantial number of discs issued by four English labels -- Hyperion,
ASV, Unicorn, and Pearl, that were manufactured by Philips and Du Pont
Optical (PDO) at their English plant between the years 1988 and 1993 were
coated with a lacquer that interacts chemically with the sulfur present in
the air almost everywhere and in the paper used in CD booklets. (Name of
manufacturer is usually engraved around the center hole on the clear side
of the disc. "Made in UK by PDO" Affected discs show an unmistakable
coppery-bronze coloration on the top side (not the clear playing side),
usually darkest at the outer and inner edges of the disc. Corrosion begins
at the edges and progresses toward the center. Music recorded on lightly
corroded areas (keep in mind that CDs play from the center out) may not be
audibly affected, but more heavily corroded areas are overlaid with a
frying-egg crackling reminiscent of scratch LPs. The corrosion is
progressive, getting gradually worse over time. Discs that are fine now
may begin to deteriorate in a year or two."

Instruction is: Collectors who find corroded discs in their collections
should send A LIST of the discs to PDO, which has agreed to replace them
(at no charge) with new pressings free of the offending chemical defect.
Residents of England have been given a toll-free number to call
(0800387063). The rest of us have been advised to write to PDO at:
Philips & Du Pont Optical UK Ltd
Philips Road
Blackburn
Lancashire BB1 5RZ
England.

PDO asks that collectors do NOT send jewel boxes of liner notes. PDO will
ONLY replace the discs. And it's not necessary (at least at present) to
send the discs themselves, just the list.

There is a list of disc #s already identified that have been know to have
some specific instances of corrosion in over 75% of the issues. If you
want the list, send me your FAX #.

Karen C. Driessen, Director Phone: 406-243-2856
Instructional Media Services FAX: 406-243-4067
Mansfield Library E-mail:
karend@selway.umt.edu
The University of Montana
Missoula MT 59812