
Planning Officer Juha Korvenpää
Digital preservation of cassette tapes
Since 1981, recordings published in Finland have been deposited by law in the National Library of Finland. At the beginning of this period, the CD was yet to be introduced on the market, and vinyl records and cassette tapes (also known as Compact Cassettes, audio cassettes or simply cassettes or tapes) were the most popular recording formats. Currently, cassette tapes account for a major share of the National Library's legal deposit collections.
Although the 1980s may not seem that distant, the cassette tapes of the time will not survive for long as physical recordings. And even if they did, what devices would we have for playing them in future? For now, cassette players are still being manufactured, but for how long? As a recording format, the cassette has undoubtedly run its course. Despite this fact, the National Library has up until recently been receiving cassette tapes as legal deposits.
The National Library's efforts to digitise recordings are based firstly on demand: the records needed immediately for research are digitised in the studio of the Music Library in Helsinki. Secondly, the National Library digitises and preserves material by concentrating on extensive bodies of material under threat, such as the legal deposit tapes. The Mikkeli-based Centre for Preservation and Digitisation has been digitising the National Library's collection of cassette tapes over the past few years.
Diverse content
The digital preservation of cassette tapes began with recordings published solely in that format. The most successful artists published their recordings in the 1980s on vinyl and later on CD. The cassette tape was less valued as a format, but was cheaper and easier to use for publishing than the vinyl record, which meant that it was a good medium for small record labels and self-releasers. The National Library has also digitised recordings that attracted little media attention at the time of their release.
Peter von Bagh, a Finnish film historian, has referred to Finnish schlager music as "the hidden memory of the nation". The idea could also be extended to the cassette tapes which are now digitised. Some of these were originally cheaply produced music cassettes featuring cover versions of the hit schlagers of the day. Although the singers are not household names and the accompaniments not as lush and refined as those of the original versions, the recordings nevertheless contain the playing of numerous Finnish musicians, with the composition of the bands changing with technological evolution. Such cassette tapes were produced and sold in great numbers in the 1980s, but you would be hard-pressed to find them on current music sites. The music of small nations or language areas holds little interest to commercial digital music stores. Is it even sold in such stores? This is why the National Library strives to preserve our cultural heritage without turning a deaf ear to fainter voices.
The cassette tapes selected for digitisation also include plenty of spoken content and recordings of various events. One almost forgotten group in terms of digital preservation are the cassettes related to textbooks and courses, which are just as threatened as other cassette tapes. Recordings reflect the fashions and current events of the time. The audio cassettes released by political parties ahead of elections are a good example, as are the recordings marketed off the back of hit TV shows. With PCs becoming increasingly common in Finland in the 1980s, the computer programme available for loading from a cassette by the Finnish band Argon was a portent of things to come.
Process of digitisation
After a cassette tape has been digitised, it is returned to the Helsinki repository. Although customers will always be provided with the digital version and the tape will thus probably never be played again, it is important to save it, for its covers and casing tell us much about its technical quality and content. Some tapes had gold-plated cases, for example, and to give customers an idea of this and other physical features of the recordings, the covers and cases are also digitised.
Digital sound can be manipulated in various ways, but audio files are not post-processed during digital preservation; rather, the files are archived with all the defects of the original recordings. This is sometimes a source of headache for the digitiser. As future listeners may not have access to the original recordings, they will not know what the recordings were like and that no errors were made in the digitisation.
No publications are digitised until their descriptive metadata have been entered into library databases. If a recording contains music, its descriptive metadata must be entered into Viola, the National Discography of Finland, whereas metadata about recordings of speech must be entered into Fennica, the National Bibliography of Finland. Determining the content of a cassette tape is difficult if it is not accompanied by its cover or other information. Sometimes the number of tracks fails to correspond to the tracklist, in which case the digitiser must ascertain which tracks are actually included on the recording. On one occasion, a missing track was found "within" another. This was an advertising tape for a record label on which an original track contained the refrain for its Finnish version.
It would be interesting to find out how many digitised versions of a given hit song are eventually produced. The number could be used to demonstrate the popularity of a song or performance. Although several versions of the same track may be digitised, this is not in vain. Recordings must be archived as part of the whole in which they were originally published. Which track preceded the other? Do all the B side tracks of a specific tape include the same technical error? Has a better version from another tape been digitised?
 Some of the cover art features computer graphics typical of the time.
Easier to use
The National Library of Finland also boasts a comprehensive collection of Finnish recordings published before the entry into force of the Legal Deposit Act in 1981. Unfortunately, the collection includes few examples of cassette tapes from the 1970s. In fact, no Finnish organisation holds a perfect collection of tapes from that period or is responsible for archiving their content. Large record companies may have archived their own releases, but many self-releases are threatened. A piece of Finnish recorded history hangs in the balance.
As the tapes contain many works by still living composers, it will take a long time before all the material now digitised is freely available online. However, the situation in Finland is good, as the National Library's music resources can be digitised and listened to on the National Library's premises. Recordings no longer under copyright protection are also available for listening through the Raita database.
Thousands of cassette tapes have now been retrieved from the collections and will be digitised and made available on the Music Library's legal deposit workstation in Helsinki. The content of many tapes may receive a new lease of life: with the material easy to search, browse and use, some works may again be found under the spotlight.
The content of the cassette tapes selected for digitisation shows that Finland was quite pluralist in the 1980s; both ends of the ideological spectrum are represented on the tapes. How the digitised data can be preserved for future generations is a topic for another article: the digitisation of cassette tapes alone is expected to require dozens of terabytes of disk space.

The cassette covers provide further information to the listener. The photograph shows detailed information about the instruments used in the recording.
Links
Fennica: https://fennica.linneanet.fi/vwebv/searchBasic?sk=en_FI Viola:https://viola.linneanet.fi/vwebv/searchBasic?sk=en_FI
Raita: http://www.doria.fi/handle/10024/66373
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The cassette tapes deposited by law contain a wide range of music, including modern art music.

Some of the covers are impressive and contain information about the performers and the record label or other publisher.
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