Re: [AV Media Matters] arsclist RE:Re-evaluating Tape

[Graeme Jaye <gjaye@retemail.es>]

At 12:24 08/06/00 -0700, Mike wrote:
>Stock for Mastering
>
>In a message dated 06/07/2000 10:22:47 AM Eastern Daylight Time,
>gjaye@retemail.es writes:
>
>>
>>  >Comments on back coating vs. non-back coating. Our rationale for using
>>  >non-back coating is the tremendous problems we have seen with back coat
>>  >failure, and no back coat eliminates that issue  - AND  we can't really
>>  >figure out what the real value of backcoat is anyhow these days. Does
>>  >this logic hold?
>>
>>  While not in the archival business, I must say I was surprised
>>  to see this statement.  I can't recall ever having seen a case of backcoat
>>  failure from any of the manufacturers.
>
>This is not surprising to me though the association of back coating with
>sticky-shed is purely coincidental. Most tapes that exhibit this
>problem are
>back coated because back coating became common at about the same
>time that
>the binder was changed.  When looking at old material, I am very
>suspicious
>of back coated tape for this reason. Non-coated tape is probably
>old enough
>to preceded this problem. This is not a factor with modern tapes, I hope.

I agree - the start of the Sticky Shed sort-of coincided with the
general introduction of back-coating.  I was trying to make the
point (probably none too clearly) that I had never experienced
back-coat failure as opposed to problems where the back coat had
been damaged by SS - which is hardly something which could be put
down to failure of the back-coat itself.

Like you - I always look twice at any early tape which is
back-coated, not because of the coating, but because it indicates
the tape is of a vintage where one should be suspicious anyway :-) .

>What is the experience with 40 year old 1.5 mil Mylar?  I have
>some 1.5 mil
>"Tenzar" tape that is extremely stiff. There were similar problems with
>Kodak's "Estar" film base. This could be a factor for very long
>term storage.

Long-term storage has never really been something with which I have
had to concern myself - unlike many others here.  The oldest tapes I
have are probably about 30 years maximum - either BASF or Ampex
manufactured.  Those which don't have SS - unfortuantely not many of
them - seem to be as good as new and still flexible.  The SS tapes
are fine once they have been baked.

>As for print-thru, it is a matter of degree.

Surely.  I rather think that the issue is being blown out of proportion.
I have some tapes here (Ampex 457) which were recorded around the end of
the '70's.  If memory serves me correctly, the recorders were set up at
380nW/m2 - which was no mean level in those days.  There is little or no
print-through on these.

Graeme Jaye
gjaye@retemail.es

Affordable Audio Restoration & CD Repair
http://www.personal-cd.com