Message-Id: <mailto:199606220008.TAA28533@library.wustl.edu> Date: Sat, 22 Jun 1996 01:57:09 +0200 From: Jacob Trock <mailto:mffkmffk@INET.UNI-C.DK> Subject: Re: Archival storage of digital media To: Multiple recipients of list IMAGELIB
>I need to know if guidelines have been established for the archival storage
>of digital media. We are embarking on a digital project of Colorado images
>and plan to store our back-up copies of the high resolution scanned images
>on both CD-ROMS and DAT tapes. What room temperature is recommended for
>longevity storage, and are there any other factors we need to consider to
>aid the life of these back-ups?
I have for the last 12 months been studying the Permanence of CD-R's and CD-ROM in relation with my Master Thesis. This is due to the rather risky desission made by the Danish archives that has decided that documents from the beginning of this year (1996) only has to be archived on CD-R's, paper is no longer needed!!
I can recommend the two following homepages:
The Commission on Preservation and Access has a lot about the subject. http://palimpsest.stanford.edu/cpa/
"Permanence, Care and Handling of CDœs" is a text made by Kodak, very informative http://www.kodak.com/daiHome/techInfo/permanence.shtml>
I suppose when you are referring to CD-ROM's you mean CD-Rœs. Here you must take some precautions.:
1. Be sure that the Recorder and the medium fits together. Ask your dealer. 2. Dust and fingerprints must especially be avioded before recording. 3. Use Kodak Infoguard disks if possible. 4. Store the disks i a stable climate. Rather a little warmer than fluctuations from your climatecontrol, but as mentioned 35-45 RH and 62 and 68 degrees Fahrenheit. 5. Avoid suddent changes in temperture because of stress between the different layers. 6. Do not write on the CD. If you have to, use it within a diameter of 50mm from the center hole. 7. Don't use labels. 8. Write the unique batch number (you find it on the inner cirkel) on the CD on the cover box together with any other text. 9. Avoid natural light. Stor it in a complete dark room. 10. Use Chemical neutral storing boxes. eg. the same for storing photographs. 11. Be careful of the top of on normal CD's. The resin used for CD's are very sensible for scratches what easily can result in damage of the reflevtive layer. 12. 60 minutes CD-Rœs seemes to last longer than 74 minutes CD-R's. 13. Make it clear that you probably have to make new copies within, let me say 15 years, because of obsolence of the DAT and CD technology 14. You are actually able to check your CD's for degradation and take the nessesary actions before it is to late and data is lost. Thaks to ECC (Error correction codes) you can check the disk for so called BLER (BLock Error Rates) and many other things. It is only to bad that such equipment easily costs 100.000 $.
I am very interested if there is anybody with specific problems in relation to the permanence of CD-R's. So all are wellcome to e-mail me.
There is ofcourse a lot to be said about the subject, but this is all for now.
Sincerely
Jacob Trock Museet for Fotokunst Brandts Passage 37-43 DK-5000 Odense C
e-mail: mailto:mffkmffk@inet.uni-c.dk