1.3 The rationale for this publication
Why does IASA now publish this document at the end of the era of traditional audiovisual carriers?
It is true that a considerable part of the worldwide audio and video holdings1—typically those owned by broadcasting and national archives of wealthy countries—have already been digitised, or are on their way to being digitised for long-term preservation. Although the new methodology of audiovisual long-term preservation had been universally accepted by the end of the 20th century, there remains a considerable part of the audiovisual legacy that is still stored on its original carriers. The main reason is obviously the lack of funds. But also lacking is a sense of urgency to complete the digitisation of content.
There is an ever-decreasing time window to complete the digitisation process before the small pool of equipment in operable condition required for the replay of traditional formats vanishes. Today, this window is estimated to be between 10 to 15 years2, which makes the provision of optimal storage conditions imperative. This is particularly important for archives in hot and humid climatic zones. The purpose of this publication is to assist stakeholders to optimise storage conditions as an interim measure before professional longterm preservation through digitisation can be funded and organised.
Additionally, optimisation of life expectancy assists the archive to follow the recommendations of IASA-TC 03 to keep the originals in good storage after digitisation as a safeguard against technical advances making better copies possible.
Under no circumstances, however, must these guidelines be misunderstood as being a complete solution. It is dangerous to assume that conventional conservation (passive preservation) may be a viable method for achieving the long-term preservation of, for example, a mixed media collection. Inevitably, deterioration will progress and will ultimately limit the retrievability of stored signals. An even greater threat is the increasing difficulty of obtaining working replay equipment and spare parts to keep machines operating. For several tapebased formats, the shortage of replay equipment is already very severe. Sooner or later, even the most carefully preserved carriers will become totally unplayable. Active preservation by following IASA-TC 03 and TC 04 is absolutely imperative.
1. The world-wide archival holdings of audio and video carriers have been roughly estimated to amount to 200 million hours. This estimate, however, includes multiple copies.
2. On average, for magnetic tape based documents this time window may be even shorter, for mechanical and optical carriers probably longer.
