Re: [ARSCLIST] Lacquer disc storage conditions

[Eric Jacobs <EricJ@xxxxxxxxxxxxxxxxxxx>]

Hi Jeff,

The two strongest bits of advice that I can give is that you need to
understand the enemies of lacquer discs:

1.  temperature variation
2.  humidity

More important than the actual temperature is that the temperature be
constant.  Temperature cycling causes the laminate and substrate to
expand and contract at different rates - over the long-term this can
lead to delamination.  In addition, temperature cycling will also
cause the exuding of plasticizer from the laminate - which in turn
will lead to laminate shrinkage (and eventual delamination) as well as
formation of palmitic and stearic acid deposits (the white waxy/oily
substance).

Humidity is the other bad actor when it comes to lacquer discs.  The
humidity at the very least hydrolizes the organic plasticizer, and
thus causes the formation of palmitic and stearic acid (PA and SA)
deposits.  The PA and SA in turn, being acids, cause an accelerated
deterioration (the acid forms in the presence of water, and the acid
forms faster in an acidic environment - creating an autocatylitic
reaction).

So check the RH (Relative Humidity) and temperature variation of your
storage options, and choose the one that offers the best balance of
temperature stability and low humidity.  It's debatable whether
temperature stability or low humidity is more important.  Assuming
that the RH is below 50%, I would choose the storage option with the
most stable temperature.


Eric Jacobs

The Audio Archive, Inc.
tel: 408.221.2128
fax: 408.549.9867
mailto:EricJ@xxxxxxxxxxxxxxxxxxx
http://www.TheAudioArchive.com
Disc and Tape Audio Transfer Services and Preservation Consulting




-----Original Message-----
From: Association for Recorded Sound Discussion List
[mailto:ARSCLIST@xxxxxxx]On Behalf Of Jeffrey Martin
Sent: Wednesday, November 19, 2008 12:10 PM
To: ARSCLIST@xxxxxxxxxxxx
Subject: [ARSCLIST] Lacquer disc storage conditions


I'm trying to advise a colleague who has recently discovered some 1960s-era
lacquer discs in her collection. (They're recorded on Audio Devices
Audiodiscs.)  What are the preferred conditions for storing lacquer discs?
She has access to cold storage (40 degrees F), cool storage (55 degrees F)
and obviously standard office HVAC storage.

Many thanks,

Jeff Martin
Chicago, IL