This is a general article to provide some information on the subject. More should follow.
For a current list of degrading analog tapes, click here.
There are multiple modes of degradation and it depends on the type of tape.
Acetate Tape
- Degrades through drying out (hydration has helped in some cases)
- Breakdown of the base through “vinegar syndrome” and possibly leading to total decompostion (although that has not been seen for tapes on any large scale)
- Damage from heat
- Damage from mold/fungus
- Loss of Lubricant is probably rare in acetate tapes. Few examples of it have been found.
- Freezing acetate tape (especially) is considered bad as many of the formulations included fatty-acid lubricants. Remember, this was from the 1940s and 1950s and one of the best lubricants of the era was sperm oil.
Polyester tape
- Binder hydrolysis (or sticky shed syndrome [SSS]) is the largest challenge faced with tapes from the 1970s-1990s. This can be partially reversed through incubation or heat treatment. While this link may not be complete, it is a great introduction.
- Loss of Lubricant (LoL) can be severe and can possibly be combined with binder hydroysis.
- Freezing is also not recommended for polyester tapes due to the potential of that tape also containing fatty-acid lubricants.
Obviously all tapes can suffer from mechanical damage and poor winds.
I expect to be discussing aspects of this in greater depth, but it is a complex subject and contradictory reports have been generated.