Tape is a robust storage medium but has two serious drawbacks, susceptability to moisture and a lack of playback machinery. Moisture has affected some tapes making them unplayable without treatment. Audio cassettes are similarly affected and their thinner tape makes them more fragile.
Well-maintained tape machines operated by skilled people are increasingly scarce.
The replay machine must be adjusted for each tape. Line-up tones for precise adjustment, usually present on studio master tapes, may be missing. Different equalisations, tape speeds, noise reduction systems and head geometry were used in tape recording.
Once lined-up the tape is digitised using a high quality A/D converter to produce the Archive Master file. This file is the most accurate digital copy possible of the analogue original, and is the digital reference for further work.
Restoration is undertaken usually to create versions of greater clarity or consistency than the master. Tape recordings can be treated to reduce hiss, and correct equalisation problems. Bandwidth limited recordings and broadband tape hiss interact making the extent of restoration dependent on final requirements.
Notes about tape recorder settings, noise reduction and line-up tones; comments on the state of the tape and any steps needed to replay it, all are part of the SIP or Submission Information Package for an archive. See metadata for more details