4.7 Containers
Ideally, carriers should be kept in chemically inert containers designed to provide sufficient protection against mechanical damage through normal handling and protection against light. With the advancement of conservation research over the past decades, the autocatalytic actions of several polymer degradation processes have been understood. Consequently, the use of airtight storage is not recommended as it could trap endogenous degradation by-products, thus increasing the rate of degradation. Generally, dust prevention should be achieved by proper insulation and air filtering of the entire storage environment. This will allow air to flow around the carriers which will help retard, if not prevent, autocatalytic deterioration. Where effective dust prevention of the entire storage area is not possible, a decision for carrier related dust prevention will depend on the relative risks of threats from internal changes in the carrier versus unavoidable external threats.26
The materials preferred for containers designed to replace damaged or inadequate original ones are polypropylene and polybutylene for magnetic tape boxes, polyethylene bags or acid free paper sleeves for vinyl discs, and acid free paper sleeves for shellac records. For cylinder storage, the Association for Recorded Sound Collections (ARSC), in collaboration with the Library of Congress, has developed an Archival Cylinder Box27.
Original containers or wrapping materials often suffer from a variety of problems: an acidic cardboard may have been used for tape boxes and disc sleeves; acidic paper for liner notes and booklets for LPs and CDs, as well as for inlays for notes for all kind of blank audio and video cassettes. In the early days of LPs, PVC sleeves were sometimes used which may cause plasticiser migration to damage LP surfaces.
Having optimisation of life expectancy in mind, ideally all carriers should be separated from inadequate original containers, wrapping and other accompanying materials. All such action should, however, be carefully considered and the improvements in storage conditions balanced against the financial and great organisational challenges such a task may demand. The great majority of containers and accompanying materials are themselves carriers of information that form a constituent part of the total document. Any loss or disorder through inappropriate cross referencing of separated parts of the document will generally cause much greater damage to the integrity and usefulness of the material than any theoretical optimisation of life expectancy. Generally, therefore, it is recommended that such exchanges be restricted to cases of obvious and immediate threat, such as PVC or other inadequate sleeves for LPs, or the removal of plastic bags from CA tapes.
26. Archives in moderate climatic zones may thus arrive at different solutions than those in hot and arid environments.
27. This container is designed for storing a single “standard-size” cylinder phonograph record. For details, contact Bill Klinger (Chair of the ARSC Cylinder Subcommittee) at klinger@modex.com.
