This format was commonly used in education and in industry and was much cheaper than the U-matic and one inch formats.
We usually see Scotch and Sony branded tape stock in this format. The Sony tape, is absolutely unplayable and dangerously so. It becomes ‘sticky’ or suffers from binder hydrolysis as Ampex audio tape commonly does. The tape will squeal loudly on any fixed guides and often stop moving around the head drum often damaging the head tips.
This tape can be restored and recovered but must be dehydrated at a very stable and constant low temperature. We’ve found this tape takes much longer than audio tape in this process and it’s also necessary to address any tape pack slip too. Custom winding machines are essential here as winding this tape on the vintage machines necessary for playback is too aggressive.
The image to the right is a tape we received and has an uneven tape pack and a small amount of mould growth too.
After dehydrating, winding and cleaning the tape and and tape pack looks more like this:
