Audiovisual preservation is a complicated topic, and one we’ve discussed several times on The Bigger Picture. Often times, digitization is the best course of action to preserve the content on at-risk formats, such as ¼-inch open reel audio tapes, compact audio cassettes, or VHS. However, improved housing can also aid in extending the lifespan of audiovisual media until digitization can occur. In 2018, the Archives was fortunate to receive funding from the Smithsonian’s Collection Care Initiative (CCI) for custom housing enclosures for an at-risk format found within the collections – 16-inch lacquer transcription discs.
Lacquer transcription discs are one of the most at-risk formats due to deterioration, inappropriate storage conditions, and poor handling techniques. Some of the most common preservation issues associated with this format are the delamination of the nitrocellulose coating, denting or bending of the metal substrate, and the formation of palmitic acid or stearic acid on the surface of the discs.
Prior to the rehousing, the discs were stored in acidic, rapidly-deteriorating paper sleeves. These sleeves not only lack the proper support for the discs during storage and handling, they also contribute to the development of palmitic acid on the laminate coating. Palmitic acid formation is part of an autocatalytic reaction, meaning that the reaction product (an acid) also acts as a catalyst for the same reaction. Therefore, both the palmitic acid present on the surface and the acidic vapor from the deteriorating paper sleeve actively contribute to the disc’s deterioration. By replacing the sleeves with custom, buffered enclosures, we can neutralize some of those acids and slow the deterioration process.
The configuration of the new housing consists of a four-flap enclosure mounted between two cover boards to create a book-like structure. During rehousing, each disc was removed from the old sleeve and placed in the new four-flap. If any label or disc fragments were discovered during rehousing, they were placed in a Mylar® sleeve or polyethylene bag and secured to the inside cover of the enclosure. The decision was made to retain any disc fragments for future digitization efforts where re-association may be able to occur through digital means, such as the IRENE technology.
As part of the rehousing project, each disc was cataloged to be able to assign individual item numbers and produce a printed label for each new enclosure. Each label contained the following metadata: asset name, collection, title, alternate ID, creator, date, duration, playback speed, and base substrate.
Once the discs were rehoused and labeled, they were placed in new clamshell lid boxes. Previously, the sleeved discs were placed in the boxes with a corrugated board spacer and bubble wrap, which could not adequately support the contents. In the new enclosures, eight discs fit snugly within the boxes, providing ample support during handling. Now that the discs have been rehoused, they are ready for long-term preservation and can be more safely transported during digitization.
- Smithsonian Institution Sound Recordings, circa 1915-1941, Accession 05-142, Smithsonian Institution Archives
- What a Groovy Idea! A Pan-Institutional Survey of Audiovisual Collections by Alison Reppert Gerber, The Bigger Picture, Smithsonian Institution Archives
- Archives Conservation in Haiti, Part 2: Audio and Video Collections by Sarah Stauderman, The Bigger Picture, Smithsonian Institution Archives