RE: [AV Media Matters] Newbie to list question - tape baking, is it

[Jim Lindner <jim@vidipax.com>]

I wish I could concur. I have seen several problems with baking -
specifically with video tapes and as a result we don't use it unless we
have used EVERYTHING else and failed - and in those cases baking usually
fails too - we restore tens of thousands of tapes a year - and we bake
less then a dozen - so it is just for last ditch efforts by us.  If you
choose to bake - I recommend a real scientific oven - we use a Blue M
which has very precise controls and very little cycling of temperature.

In video, consider that we are dealing with helical tracks, not
longitudinal ones. I cannot say why baking does not work, because we
have not done the research - but on a practical level some tapes seem to
respond in a non-linear way and as a result the base material may
distort just enough to make tracking just a bit more dicey - and since
in old tapes there has already been some distortion - the difference is
enough to make them uncorrectable.  Video tracks are much smaller then
audio tracks in most formats so the results may just be more obvious.
Even with baking, we

also - btw

The process of baking tapes is patented.  No kidding - it is.  Using a
patent without permission is not a good plan. Ampex has never followed
it up - and I have heard several people say there is prior art - BUT the
fact remains that the patent is unchallenged - therefore it stands. And
if you do use it - one day there could be a lawyer knocking on the door
- not a happy story.  If you look at the patent there is some
interesting information - one is that it appears they never tried it on
video tapes.  In any event - beware.

jim

smolians@erols.com wrote:
>I can only second this basic information.
>
>I use an environmental chamber which gives a greater degree of control.
>Having done hundreds of these in all configurations (I had to bake some
>non-US cassettes recently.  I wonder what they were slit down from...).
>
>I've found that wider tape requires more bake time.
>
>Too high a temperature causes print-through.   I bake a bit more slowly
>at a
>lower temperature, both for myself and other local studios, and have
>never
>haad a failure- so far.
>
>Steve Smolian
>
>-----Original Message-----
>From: Graeme Jaye <gjaye@retemail.es>
>To: AV-Media-Matters@topica.com <AV-Media-Matters@topica.com>
>Date: Monday, December 20, 1999 5:39 PM
>Subject: Re: [AV Media Matters] Newbie to list question - tape baking,
>is it
>wrong?
>
>
>>Hi WIll
>>
>>At 06:02 18/12/99 -0800, you wrote:
>>
>>>I've got a circa 1982 Ampex 2" 16-track tape that I want to transfer to
>>>ProTools. It has been stored in various conditions and levels of
>>>humidity since that time, but has not been played since then. I've been
>>>told that I'll need to "bake" the tape to keep the acetate from coming
>>>off
>>>on the heads. Is this normal (and is it the only way to do it right?)
>>
>>This is a well-known problem which affects tape (not only Ampex) of this
>>vintage.  It is to do with the binder chemistry being changed around
>>that
>>time for something which (over a period of time) becomes 'sticky'.  It's
>>commonly known as 'sticky shed syndrome' and it's not the acetate which
>>comes off, but the iron oxide!!  If I recall, Graham Newton has some
>>information on his website about this subject
>>(http://www.audiorestoration.com) which you might like to have a look
>>at.
>>
>>Baking the tape is the accepted solution for the problem, although it
>>does
>>*not* effect a permanent cure.  Something like 6-8 hours at 130-140
>>Farenheit is the usual sort of figure recommended.  I have baked many
>>tapes
>>(must be well in excess of 100 by now) and have not had a failure so
>>far.
>>All my tapes have been 1/4" masters, but I don't see that a 2" would be
>>any
>>different.  It does no harm to leave the tape for longer, but I would be
>>very wary of going over-temperature.
>>
>>You can be fancy about it and use a temperature controlled, electric
>>oven
>>(not a gas one).  Personally, I do mine in a cardboard box, about  2 ft
>>cube, with the tapes supported on a wooden dish rack, two electric light
>>bulbs, a dimmer unit and a photographic thermometer :-)
>>
>>After baking, spool the tape a couple of times before playing.
>>
>>>This person said that after baking, the tape would only be good for
>>>about
>>>2 to 4 plays, so I want to make sure.
>>
>>I don't think it is a case of the number of plays, so much as the time
>>it
>>will take for the binder to re-absorb moisture from the atmosphere
>>(which
>>is what causes the problem in the first place).  After baking, I place
>>the
>>reels inside a sealed polythene bag (assuming I am not going to use them
>>immediately).  They have certainly been playable after a month when
>>treated
>>this way.
>>
>>>Aside from the difficulty in finding
>>>an old 2" machine with a 16-track head (I know you can play them on a
>>>24-track machine with some level of reliability) - I'm cautious about
>>>going forward. I'm located in Austin, TX.
>>
>>I would have thought that many studios still running that type of
>>machine
>>would have a 16 track headblock as well as a 24 track one - but I'm open
>>to
>>correction on this point.  You can certainly *play* a 16 track tape
>>using a
>>24 track block, but some of the tracks are not covered properly and the
>>head is also partly reading the guard band, which will lower the
>>signl/noise ratio of course.  I used to know which tracks were which and
>>the amont of level correction required, but I'm afraid it's a long time
>>since I last did this and my memory fails me now.
>>
>>The one thing you should *not* do is to try playing the tape before
>>baking
>>- apart from the fact of losing a lot of information off the tape, it
>>will
>>make one heck of a mess of the headblock and guides!!  Otherwise, I
>>would
>>say this is a reliable method of recovering these tapes.
>>
>>
>>Graeme Jaye
>>gjaye@retemail.es
>>
>>Audio CD stuttering?
>>DVD dodgy?
>>CDROM not reading?
>>PlayStation stationary?
>>Saturn not flying?
>>
>>No Problem - Check this out!!!
>>http://www.personal-cd.com
>>
>>
>>
>>

Jim Lindner - President
VidiPax - The Magnetic Media and Information Migration Full Services
Company
Telephone 212-563-1999
www.vidipax.com
Moderator of A/V Media Matters@topica.com