At 01:31 PM 2008-08-27, Michael H. Gray wrote:
>I'm curious to know how master tapes 'deteriorate' Is it in the
>physical carrier or in the magnetic signal?
Yes, and no.
The biggest problems for newer (1970s-1990s) tapes is binder
degradation--the breakdown of the "glue" that holds the magnetic
particles to the base film (physical carrier).
The biggest risk, but not yet a huge problem, for older tapes that
used cellulose acetate as a base film is vinegar syndrome which
destroys the base film. This has been a huge problem with magnetic
motion picture film (for sound--essentially thicker tape in film
widths with sprockets). We are not sure if these mag films are an
outlier or the "mine canary" for what will happen with the thinner,
narrower acetate audiotapes.
There are also risks that can damage the magnetism entrusted to the
tape, but binder problems are, by far, the worst challenge today.
Of course, we wish many tapes had been recorded better as well!
Look for my article on the subject in the next issue of the ARSC Journal.
Richard L. Hess email: [log in to unmask]
Aurora, Ontario, Canada (905) 713 6733 1-877-TAPE-FIX
Detailed contact information: http://www.richardhess.com/tape/contact.htm
Quality tape transfers -- even from hard-to-play tapes.