RE: [AV Media Matters] Print-through

[Graham Newton <gn@audio-restoration.com>]

Jim Wheeler <Jimwheeler@aol.com> said to the AV list...
On the subject: RE: Print-through

>Who did you talk to at Quantegy?
Jay Zacharias

>The baking tests we ran at Ampex was over a
>three year period and we baked some of the same tapes several times.
I'm not suggesting that you can't bake several times, and I have done so.

>My question is why bake a tape several times?  I bake it once and copy it.
My point precisely.  HOWEVER, the caveat of my comments was:-

**************************************************************
>Since technology will progress, there will doubtless come a time when
better
>transfer or restoration means are at hand and it will be desirable to
>re-transfer the deteriorated tape.
**************************************************************

>Regards print-through.  The temperature in the print-through equation is
in
>KELVIN--not Fahrenheit, so the few degrees increase normally used for
baking
>should have little or no effect on print-through.
Agreed.
I did not deal with print-through, since the topic had morphed to
sticky-shed/baking, although it retained the original title.  My initial
comments were a response to the "bake first, ask questions later" comment.

>Regards tape packs.  The layer-to-layer forces are the greatest about 1/3
of
>the way out from the hub.  The forces can become so great that they go
into
>compression.  When that happens, the layers distort.
>If the outer radius divided by the inner radius is less than 2.5,  these
>forces are greatly reduced.  That's why I prefer reels with large diameter
>hubs.
I think most of us would prefer the large hub reels for a variety of
reasons,
however 1200 feet of 1.5 mil tape seems to want to occupy an entire small
hub
7" reel and with so many of them out there, it is a losing battle to try and
fight your way upstream!  When baking a small-hub tape, it would make sense
for the reasons noted, to move the tape to a large hub reel, where possible,
before returning it to storage.

... Graham Newton

--
Audio Restoration by Graham Newton, http://www.audio-restoration.com
World class professional services applied to phonograph and tape
recordings for consumers and re-releases, featuring CEDAR processes.