Re: [AV Media Matters] metal vrs wooden shelving for VHS tape

[smolians@erols.com]

Yup.  Big fans- and plenty of them.  Smelled great, too.  And noisy- you
wouldn't believe.

Steve

-----Original Message-----
From: joe salerno <salernoj@swbell.net>
To: AV-Media-Matters@topica.com <AV-Media-Matters@topica.com>
Date: Tuesday, April 04, 2000 3:04 PM
Subject: Re: [AV Media Matters] metal vrs wooden shelving for VHS tape

>Please define forced evaporation. Do you mean fans? Heaters?
>
>Joe Salerno
>Video Works! Is it working for you?
>PO Box 273405 - Houston TX 77277-3405
>http://joe.salerno.com
>Fax: 603-415-7616
>----- Original Message -----
>From: <smolians@erols.com>
>To: <AV-Media-Matters@topica.com>
>Sent: Monday, April 03, 2000 6:17 PM
>Subject: Re: [AV Media Matters] metal vrs wooden shelving for VHS tape
>
>
>> I did the post-flood disaster survey and recovery plan for the Boston
>Publc
>> Library about 2 years ago.  The shelving for the sound archive, stored in
>> the basement, was wooden. A water main had burst and flooded to a height
>of
>> about a foot when first inspected.  All records and tapes above the
bottom
>> shelf were dry.
>>
>> The following day, the water had wicked up the wood and soaked the bottom
>of
>> the materials on the next shelf.  It continued to the following one in
>some
>> sections.  The basement was pumped out, of course, but the wood remained
>> damp for some time.  The humidity was reduced by forced evaporation.
>Anyone
>> for moldy oldies?
>>
>> At last count, 77,000 records were lost.
>>
>> Steve Smolian
>>
>>
>> -----Original Message-----
>> From: kbradley@nla.gov.au <kbradley@nla.gov.au>
>> To: AV-Media-Matters@topica.com <AV-Media-Matters@topica.com>
>> Date: Monday, April 03, 2000 5:32 PM
>> Subject: RE: [AV Media Matters] metal vrs wooden shelving for VHS tape
>> storage
>>
>>
>>>>Does anyone have data on magnetizing of metal shelving from long
>>>term
>>>>storage of VHS cassettes?  Any suggestions on how to mitigate?
>>>
>>>
>>>I did some measurements on metal shelves using a magnetometer to see if
>>>there were any fields strong enough to damage a tape.  The short answer
>is,
>>>I couldn't find any.
>>>
>>>On some of the corners of the folded metal shelves at zero distance the
>>>highest field I have ever found was around 10 oesteds DC, which is about
>a
>>>quarter of what the Knight article in the IASA phongraphic bulletin
>defined
>>>as a problem, and about half of what we at the NLA adopted as a minimum
>> safe
>>>standard.  Given that the field strength drops in inverse proportion to
>the
>>>square of the distance, the actual strength at the first layer of tape
is
>>>much much smaller.  So we concluded, that while it is feasable to
>magnetise
>>>a steel shelf to such an extent that the residual field may be damaging
>to
>> a
>>>low coercivity tape, no-one is putting that sort of effort in.  I still
>>>borrow a magnetometor and check new shelves occassionally though.
>>>
>>>Wood shelves have a whole heap of potential problems associated with
>> exuding
>>>gaseous and other substances which your average conservator can tell you
>>>about.  Metal are a better bet.
>>>
>>>Kevin Bradley
>>>a/g Manager: Digital and Audio Preservation Resources
>>>National Library of Australia
>>>Canberra   ACT 2600
>>>AUSTRALIA
>>>
>>>Tel:  +61-2 6262-1381
>>>Fax: + 61-2 6262-1653
>>>Email: kbradley@nla.gov.au
>>>NLA home page: http://www.nla.gov.au
>>>Change is inevitable, except from a vending machine
>>>
>>>> ----------
>>>> From: mha@durab.com[SMTP:mha@durab.com]
>>>> Sent: Saturday, 1 April 2000 7:33 AM
>>>> To: AV-Media-Matters@topica.com
>>>> Subject: [AV Media Matters] metal vrs wooden shelving for VHS tape
>>>> storage
>>>>
>>>> Does anyone have data on magnetizing of metal shelving from long term
>>>> storage of VHS cassettes?  Any suggestions on how to mitigate?
>>>> thanks
>>>> mark
>>>> Mark Hopkins + Associates
>>>> 28 Warland Avenue
>>>> Toronto ON M4J 3G2 CANADA
>>>> tel: 416-421-5369
>>>> fax: 416-421-7788
>>>> e-mail: mha@durab.com
>>>>
>>>> Monitors Comment:
>>>> This comes up now and then - the short answer -get  Metal Shelves not
>>>> Wood.
>>>> VHS tapes will not magnetize shelving - but people usually ask about
>> metal
>>>> shelving demagnetizing VHS cassettes - that is not an issue either
>unless
>>>> 1. There is a VERY strong magnetic field CLOSE to the tapes for a LONG
>>>> TIME
>>>> 2. The shelves have previously been used with rare book bookends that
>> have
>>>> VERY STRONG magnets that will sometimes magnetize the shelving - but
>>>> whether
>>>> the field strength is strong enough to do anything is questionable
even
>> in
>>>> that case.
>>>>
>>>> jim