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Preservation of Modern Information Carriers:
Sink or Swim
Many archivists have, no doubt, had waves of anxiety wash over them in the midst of creation, documentation and preservation of modern information carriers, represented by optical discs, magnetic discs and magnetic tapes. Some find themselves in strange waters when they take the plunge to preserve or reformat these records, yet will feel like helpless non-swimmers if they fail to act. The ASA's recent two day workshop: Preservation of Modern Information Carriers, led by CCI conservation scientists Joe Iraci and Tom Strang, certainly forced participants to get their feet wet. The technical, practical and market realities of these non-traditional information carriers were explored in a combination of thought-provoking lectures and discussions.
Preservation of Modern Information Carriers involved an examination of the structure, composition and various formats of optical discs (laserdisc; the whole range of CD's including read-only, write-once and erasable; and DVD's), magnetic discs (hard discs and floppies) and magnetic tapes (computer: digital; audio: analog or digital and video). There were game attempts to explain how these records actually work and, more importantly, how they should be handled and stored, how long they might last and how they may be recovered in disaster situations.
Some points that stood out for me included:
- although CD's can be quite robust, top-side damage to the metal layer can be much more devastating than bottom-side scratches; avoid pressure sensitive labels and write on the clear hub area
- "laser rot" (corrosion and lacquer problems) is an issue with earlier CD's, not an epidemic; dye stability is a concern with today's CD-R's - shoot for the light green (phthalocyanine) rather than blue and choose brand names
- audiotapes stored in the "played state," that is "tails out," enjoy both the benefit of an even tape tension achieved only when played through (not fast-forwarded or rewound) and "print -through" will not precede audio signals, but rather follow them, which is easier to remedy.
- Since 1956, twenty-seven manufacturers have produced videotapes, 31 formats of 50 are no longer in production. However, the formats are very standardized and are documented and controlled by the Society of Motion Picture and Television Engineers (SMPTE).
Interestingly, one of the key points raised at the workshop with respect to storage environment of modern information carriers has broad applicability to other archival media, including traditional records. Universal improvement in longevity will be achieved by lowering storage temperature and relative humidity below the norms ingrained into heritage preservation culture. The lifetime of these and other records will be doubled for each 5° C decrease and by halving the RH. A fascinating discussion of this revelation is argued in Guidelines for Humidity and Temperature for Canadian Archives, by Stefan Michalski, CCI Technical Bulletin 23, 2000. All archivists would do well to examine or re-examine this study and think about how we might work on the single-minded air conditioning contractor, the stubborn Supervisor of Maintenance or the disbelieving manager.
The presenters of Preservation of Modern Information Carriers are working their way across the country. A good representation of individuals and institutions was included among the registrants, which bodes well for Alberta. This workshop is worthwhile for those wading along the shoreline of the sea of new media as well as those responsible for a variety of record types. Thanks to the ASA and CCI for this opportunity.
Don Bourdon
Whyte Museum of the Canadian Rockies
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