On 19 March 2019, 16 participants gathered at the Provincial Archives of Saskatchewan in Regina to increase their knowledge of the preservation of audio-visual records, from Donald Johnson, Special Media Archivist. Audio-visual records are a challenge because they require equipment to be accessible. Some of that equipment is becoming harder to find, and in good enough condition to use. The focus was on audio recordings, such as on audio cassette, reels or CDs, and moving images on a variety of media such as video, DVD or Blu-ray, but it also touched on film.
There are a wide variety of formats that have been used over time. Many have not been produced with preservation in mind, and many individuals buy them without thinking what archivists would like to preserve. Depending on the acquisition policies of different institutions, certain media may be found in one type of institution and not in others. For example, the records used in radio stations are less likely to be in personal fonds.
The environment within which audio-visual records are stored is important for general preservation, and should be an early consideration in the preservation of all records. Beyond that, there are additional strategies for the preservation of the records. We need to keep in mind the distinction between the media (the carrier) and the format (the structure).
- · Refresh – which is to copy to the same media, in the same format, e.g. from one CD to another.
- · Conversion, which is putting something in the same format onto a different medium, e.g. VHS to DVD, or
- · Migration, which is moving a record into a different format on a different medium, such as digitizing a videotape.
A couple of challenges that often arise in these collections are:
- · Vinegar syndrome, where film on an acetate base, stored in less than ideal conditions, starts to break down, causing acetic acid to be released. This in terms can affect other materials around them. Putting the film in a proper environment and housing them in cans with vents can help. It is also possible to get specialized silica gel packs to absorb the acetic acid fumes.
- · Sticky shed syndrome for magnetic tapes, especially reel-to-reel audio recordings. If the tapes are baked at 38 degrees for 6-8 hours to temperature can penetrate, this increases the chance to play the recording without all the magnetic particles falling off in the machine
In taking any steps to preserve audio-visual records, it is important to have adequate documentation of the original item and of the preservation strategy, to help assure authenticity and integrity of the record. The strategies taken might depend on the nature of the record, for example an oral history vs a musical masterpiece may require different levels of sophistication in digitization. In all cases, we need to document what we are doing with the record, so that the transition from one format to another is understood and trusted.
Should we keep the original records once we have digitized them? Different strategies are being developed to improve access to original recordings. For example, the Northeast Document Conservation Center has developed the ability to digitize wax cylinder recordings without touching them. Digitization practices of film have improved over time so we may want to try again after initial attempts to migrate the recordings. Should digitized copies become the “original record”? Does the donor agreement specify that the original will always be the official copy, or could a migrated version into a more stable format become the “original’? This may depend on our institutional policies.
|Turntable and reel to reel audio station|
Another had a Tascam cassette deck and a CD player attached with cables to an audio interface and laptop computer.
|Cassette deck and CD player with Audacity|
Two additional stations were set up for video recordings. One included an inexpensive video digitization device, while the other was more sophisticated video transfer station, with both VHS and DVD player/recorders, and a TV, so we could compare the effectiveness of the two approaches. As with the audio stations, these were equipped with step-by-step procedures to make the copies, so we would have a feel for how to approach this work ourselves.
Several participants examined the equipment used and took pictures of the setup, as they determined how to set up digitization stations in their own institutions. Several tools were mentioned, such as Audacity already referenced, and Media Info[ii], which is software that can analyze media files and display metadata needed to complete the documentation required.
|Film preservation station.|
These were a few highlights I gleaned from the workshop, and I learned a great deal. This workshop was a great opportunity to see several digitization scenarios in action, and to talk to someone with solid experience. I still have terms like checksum and bit depth and sample rate floating around in my brain with no fixed address but, along with other insights not considered before, I have a better idea now of what to do with them. This gives me confidence to move forward with developing clearer procedures in this specialized area of archival work. It was a day well spent, thank you Donald.
Ailsa Hedley Leftwich
Canadian Bahá'í Archives