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Re: [ARSCLIST] Baking tapes and high frequencies
At 10:57 AM 4/12/2005, Peter@xxxxxxxxxxxxx wrote:
Periodically, someone re-emerges with the assertion that baking analog audio
tapes has a negative effect on high frequency reproduction. Does anyone
have any DATA, or references to actual studies, that support this claim or
other claims that baking tapes has serious negative effects?
Thanks, Jim L. for the more detailed explanation of your dimensional memory
tests. That is indeed important for videotapes. One question in that
regard, and I see you mentioned the cleaning aspects later, but could the
lower RF have been due to different surface properties (rougher?) after the
baking?
Lance, I agree with your points about why worry about re-baking. I've
actually done that when I was unhappy with the first transfer (a head clog
that got past the cleaning), but it's rare. The only other time I re-baked
was when I was first starting in this business and did a transfer on a
ReVox A77 and wanted to go back and use the Sony APR-5000 for a slightly
cleaner transfer.
If this is brought up by Richardson's presentation tonight at the AES NY
Chapter, Chris Lacinak and I have been talking more about this off-list. I
think he's going to bring up this MRL test. I heard Richardson at the ARSC
conference and left with a few questions, but I also thought that some of
what he was saying needed further investigation. While he claims that his
testing showed the backcoating to cause the sticky shed, I'm questioning if
it's more like the interaction between a xerographic copy and a vinyl binder.
I certainly wished that the ARSC presentation provided more data and that
the demos were better presented.
One can never be sure what will happen to any given tape due to its unique
manufacturing profile (even tapes with the same "part number" are not
identical as manufacturing processes/formulations may have changed over
time) and its unique care/storage/use profile over time.
I posted this to the ARSC and AMPEX mailing lists on 8 April 2004 and I
think it bears repeating:
From: "Richard L. Hess" <arclists@xxxxxxxxxxxxxxx>
Subject: [ARSCLIST] Sample of one tape baking test--Good news
I received two 1988 Magnetic Reference Laboratories 1/4-inch test tapes in a
parts deal from New Zealand.
Both were made in 1988 on Ampex 406 tape. Both were suffering from the dreaded
sticky shed.
I baked both for about three hours approx on 4/1 but didn't send them back to
MRL until 4/5 and they arrived yesterday and were tested today. [4/8/2004]
The IEC 15 in/s one wouldn't play due to continued sticky-shed problems (I'm
getting it back for more baking). [and have yet to do that]
The NAB 15 in/s one played fine and according to Chuck at MRL that its levels
appeared to be as accurate as when it left the factory. He was actually rather
impressed at how good the graph looked.
While obviously a sample of one can't prove that baking is good, it is my
assertion that this test increases the credibility of what, to many of us, has
appeared to be a transparent process over a long period of time.
Use-based damage to the test tape would typically be in the same direction as
the alleged baking damage (the loss of short-wavelength/high-frequency
material), therefore, there is almost zero possibility that the two cancelled.
Further testing would be useful, but I think this is as controlled a test
as we
are likely to see today, although I could see recording and playing on sticky
tape, but that is less of a true test than this, because how do you record on
sticky tape before baking?
I would like to thank Jay McKnight and Chuck of Magnetic Reference Lab for
their
support of this testing, and also the 16-year custodian of the test tape who
apparently kept it in good condition.
Cheers,
Richard
Richard L. Hess email: richard@xxxxxxxxxxxxxxx
Vignettes
Media web: http://www.richardhess.com/tape/
Aurora, Ontario, Canada (905) 713 6733 1-877-TAPE-FIX