Most Video and Audio tapes are made from a plastic backing material coated with a magnetisable coating and are referred to as Magnetic tapes. Magnetic tapes were never designed to be a permanent archiving solution and degenerate with time. Magnetic tapes need to be copied to ensure the original content is preserved and able to be played as when recorded. In the past this was done by copying tape to tape with the new copy being a newer and more advanced format. The unfortunate consequence of using this method is generational loss. Every time you copy a tape using this method there is a quality loss and the amount of loss is dependent on the condition and quality of the player, file format, tape and recording device.
Digital file formats started to be developed in the 1970s but it wasn’t until the introduction of CDs (1998) for audio and DVDs (2005) for video that magnetic tapes began to be replaced by these digital media. Although high in quality, CDs and DVDs were not considered a good enough quality for archiving and most institutions still continued the practice of tape to tape copying. In the late 1990s the BWF audio file format was developed. The BWF file format was a high quality uncompressed format and soon archives and institutions began to consider the BWF file format. Suitable Video formats followed but because of the enormous file sizes generated a huge amount of storage was needed and thus the take up was slower. With time, file storage became more efficient and smaller in size. Video cameras gradually stopped using tapes to store files and in 2016 the last VHS video cassette recorder was produced. Around the same time Sony ceased production of its broadcast range of cameras and VCRs ending the era of magnetic tapes.
Many factors determine the rate of degeneration of magnetic tapes with the main factors being:
- The age of the tape.
- How the tape was stored. The higher the temperature and humidity magnetic tapes are stored at the quicker the tape will degenerate.
- The format of the tape. Just because a tape is a more recent format, such as most High Definition formats, it will not necessarily degenerate slower. Newer formats tend to be of smaller diameter and thinner in thickness which means their physical frailness makes them susceptible to degradation.
- Quality of the tape. Tapes of better quality generally are less susceptible to deteriorate.
The National Archives of Australia and the National Film and Sound Archive jointly released the “Deadline 2025” which states the need for all audio and video magnetic tapes be copied by 2025 or risk neither been able to be copied. ADD LINK As dramatic as this statement sounds it does emphasise the need to digitise any magnetic tapes as a high priority. Some formats will be able to be copied after the deadline but for some formats it’s already too late. Even if magnetic tapes stored in ideal conditions and are in good condition the biggest danger is obsolescence of Video and Audio tape players. With some older analogue formats players have not been for over 40 years. A good example of player obsolescence is the 1 inch open reel video format. This format was the main stay of the broadcast industry from the seventies and eighties and was used by some broadcasters well into the mid nineties. This means that the majority of video produced, including television shows, series, documentaries, news and current affairs programs, even commercials were stored on 1 inch tapes. The small number of good operational 1 inch players is a real concern and there is a risk some of these valuable shows will be lost.
Two of the biggest dangers to magnetic tapes are “Tape Shedding” and “Hydrolysis”. Tape shedding is where the magnetisable coating detaches from the backing material causing the players playback heads to clog. Cleaning the tape helps in most cases but when shedding is severe enough can cause the tape to be unplayable. The example below the amount of material that has detached from a tape during cleaning.
Hydrolysis is where the tape has absorbed moisture from the air. This causes the tape to “stick” to the playback heads causing the playback image to stutter. If severe enough the tape will stick to the playback heads and be unplayable. In some cases there is a fix for this which involves “Baking” the tape in a laboratory oven to draw out the moisture. Treatment of both of the above conditions should only be performed by experienced technicians. Below is an example of Hydrolysis showing first the tape, in this case an early EIAJ tape (a early video format pre dating VHS tape), showing first the tape sticking and secondly the resultant playback image.
The above is a brief description of why you should copy all of your audio and video magnetic tapes and if you want some more information please contact us on:
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