FIAT/IFTA World Conference 2024

In 1980, B.B. King gave his second concert at the Montreux Jazz Festival. The recording was made by Swiss sound engineer Philippe Zumbrunn on CJ 87 Pyral tape in NAGRA Master analogue audio. Unfortunately, the polymer base sticks to the adjacent magnetic coating, making it unplayable. When read, the tape sheds and clogs the player.  UNESCO’s Magnetic Tape Alert Project found that degradation problems are common to millions of historic tapes. The Australian National Film and Sound Archive even stated ‘Tape that is not digitised by 2025 will in most cases be lost forever’. But is it so?

The “Play it Again” project at the Paul Scherrer Institute (Switzerland) uses chemical and physical characterisation to better understand magnetic tape degradation in a collaboration with the Montreux Jazz Digital Project. For Pyral tape, infrared spectra are consistent with other tapes suffering from ‘sticky-shed’. As it is not the magnetic binder that is at fault, but rather the polymer base, this suggests a need for a more careful classification of tape degradation pathways to aid conservation. Physical characterisation using electron microscopy shows micrometre-scale cracks across the tape. Heat treatment does not heal the cracks, meaning that this degradation is irreversible and the magnetic signal will become intrinsically noisier with time. Similarly, in collaboration with the British Film Institute, we are investigating degradation in video tapes. Some of our research questions include: Are physical treatments helping the tapes, or just mitigating the decay symptoms long enough to allow for digitisation? Is attempting to treat tapes doing more harm than good?

So, is 2025 a final deadline? Probably not, however degradation is generally irreversible, eventually rendering magnetic tapes totally unplayable using conventional technologies. We are presently developing a contactless solution using synchrotron X-rays for recovering the recorded information from such degraded tapes.