The HTV Wales archive is a significant record of Welsh popular culture, politics and history captured on both film and video and it constitutes a large part of the Screen and Sound Archive. An archive of that size and age will have an assortment of conservation challenges, especially in the area of restoration. By far the most common problem with old tape is Sticky-shed syndrome (SSS) or hydrolysis. SSS is symptomatic of the breakdown of the tapes’ polyester binder due to absorption of moisture.
The tell-tale squealing of the tape as it passes over the playhead and the accumulation of dirty deposits upon the guide and playhead indicate a tape has SSS. A tape with SSS will, amongst other issues, exhibit ‘crabbing’, i.e. the moving from side to side of the moving image, and if not treated continued playback could further damage the tape.
So how do we restore that believed lost episode of ‘Gwesty Gwirion’? The answer may surprise you! The standard practice is to bake the tape at low temperatures for relatively long periods of time, such as 130 °F to 140 °F (54 to 60 °C). Strictly speaking we don’t ’bake’ our tapes but instead use a commercial food dehydrator that removes all moisture from the tape pack. How long we do this to the tape will depend on the severity of the SSS; up to a week we’ve discovered is time enough. We have been successful with the majority of the tapes that have undergone the process, with many lost gems brought back from the brink of oblivion. You can see some of them on the ITV Wales YouTube channel or view them at the Library.