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Preservation Guide - Compendium of Technical Information

(much to do here)

MigrationTable

Media

• Identification
• Packaging
• Handling
• Storage
  (maybe these headings are wrong, or should be sub-headings under division by media type)

CD

• basics
• properties
• archive format
• suppliers
• do's and dont's

Use of writeable CDs and DVDs (for archive purposes) is NOT recommended by IASA (TC-04: http://www.iasa-web.org/tc04/ http://www.library.uiuc.edu/lsx/books/Mar06/bradley.htm), though they are cost-effective and useful for access copies. CDs and DVDs can be written in a secure fashion, but it is difficult: the media have to be high quality (how do you check that? The BBC has a £2000 checker, and buys in large batches to a set specification). The media have to match the CD / DVD writer, and the writing parameters have to be optimised for the media. Then each newly-burned CD must be immediately checked for readback. Finally for any large collection there should be sample testing every six months, to spot degradation.

There are more problems: CDs and DVDs are easily damaged (scratched), and many types can easily be damaged by pollution and especially by ultraviolet light. So any master material on CD or DVD has to be protected, just like master film or tape materials.

But if you are going to use these optical media, then CDs and DVDs with a gold reflective layer are best, especially those with the very stable phthalocyanine dye (which seems only to be available on CDs).

Companies that produce gold reflective layer, phthalocyanine CDs include:
MAM-A http://www.mam-a.com/products/gold/index.html
Delkin Archival Gold http://www.delkin.com/products/archivalgold
HHB CDR74Gold http://www.hhb.co.uk/hhb/uk/hhbproducts/media/detail.asp?product=CDR74Gold (although the description of the HHB CDR74Gold does not specifically say the reflective layer is made of gold)

Useful information is here:
http://en.wikipedia.org/wiki/CD-R
http://www.tasi.ac.uk/advice/delivering/cdr-dvdr.html
http://www.nla.gov.au/padi/topics/53.html
http://www.cdmediaworld.com/hardware/cdrom/cd_dye.shtml
http://www.cdmediaworld.com

Articles:

• Risks associated with the Use of Recordable Cds and Dvds as Reliable storage Media in Archival Collections - Strategies and Alternatives - By Kevin Bradley, National Library of Australia, Canberra http://unesdoc.unesco.org/images/0014/001477/147782E.pdf
• Care and Handling CDs and DVDs : a Guide for Librarians and Archivists; Byers, Fred R. (Date Created: May 2003) http://www.itl.nist.gov/div895/carefordisc/index.html
• Longevity of CD Media Chandru; J. Shahani, Basil Manns and Michele Youket; Library of Congress, Washington DC, USA http://www.loc.gov/preserv/studyofCDlongevity.pdf

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Equipment

• Basics
• Setup
• Operation
• Transfers

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Terminology
Very useful preservation glossary from MIC: http://mic.imtc.gatech.edu/presglos_1.htm

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Tips and Tools

Film

Conversion Factors and Calculators
Frames per second = FPS:
Standard for sound films: 24 frames per second
Silent films: no standard, but 16 and 18 frames per second are common

Converting length to time:
Metric 35mm: length in meters x 52.49 / FPS = time in seconds
(3.2808 feet per meter * 16 frames per foot)

16mm: length in meters x 131.2 / FPS = time in seconds
(3.2808 feet per meter * 40 frames per foot)

For recidivists: 35mm: length in feet x 16 / FPS = time in seconds

16mm: length in feet x 40 / FPS = time in seconds

Rules of thumb:
35mm: @24 FPS: feet/90 = time in minutes

@16 FPS: length in feet equals time in seconds (how nice)

16mm @24 FPS: feet/36 = time in minutes

Online tools are here:
The Kodak website has a handy on-line "Film Calculator" for just about any format and frame rate: http://www.kodak.com/US/en/motion/filmCalculator.html

Plus lots of other handy tools for the film user:
http://www.kodak.com/US/en/motion/support/index.jhtml
http://www.kodak.com/US/en/motion/support/iaTools.jhtml?id=0.1.4.3&lc=en

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