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

[mwcpc6@aol.com]

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.

As for thickness, curl and set can be problems with the thicker
tape. Certainly 1.5 mil acetate can have so much curl that it can't
be played.  1 mil is usually flexible enough to flatten out with
high enough tape tension. 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.

Head contact problems might occur if the 1.5 mil archival tape is
reproduced on machines that have had their heads shaped by general
use with 1 mil tape. This would be a matter of standardizing on one
type of material for the site.

As for print-thru, it is a matter of degree.  I have heard long ago
of the practice of winding a layer of blank tape between the
archival tape turns for storage, feeding it from a separate reel.
This was in the days of low coersivity brown oxide material.  Modern
low-print tape should have less print through than even that
procedure produced then. The choice of coating will probably be more
important than the 50% increase in spacing between layers.
Protection from heat, mechanical shock and magnetic fields is
important too.  The advantage of the 1.5 mil thickness for reducing
print-thru would have to be weighed against its cost and the
practicality of standardizing the machines to this material.

Mike Csontos