Re: [AV Media Matters] ME Tapes for DV format

[rohre@ARLUT.UTEXAS.EDU]

In evaluating any tape media, the physical inspection of the winding of the
tape pack can show if stiction, edge damage, cupping indicating
environmental
stress, and other handling issues have affected its quality and playback
before mounting the media in a drive.

After determining that the tape cassette or reel has media upon it that
unwinds without stiction, then one can move on to playback testing that
includes inspection of the signal envelope.  But first do other physical and
audible inspections, such as listening for tape squeal as the media unwinds
in
the drive.

The recently discussed inspections for binder failure, and ruboff of oxide
should be done before playing an unknown condition tape. Needless to say,
verify the drive with a known good tape copy, before examining Masters.

In any case where you have not played the media in recent past, you should
approach the playback as handling an unknown, and to prevent damage, you
should move only a little media through the drive, then stop and inspect the
drive for abnormal deposits.  This will lessen the embarrassing instances of
delaminating a one of a kind tape.

Metal evaporated formulations are fairly new; have any of our list
authorities
run onto problems with these where the baking solution done with oxide tapes
to salvage a binder breakdown is also appropriate for  ME media?  (Since
metal
is evaporated onto a plastic substrate, there is not a binder to hydrolyze I
would think.  But, does the substrate suffer from reversible humidity
problems?)

Stuart M. Rohre
Univ. of TX, Applied Research Laboratories