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[BKARTS] CD-R longevity and recording techniques for archival recordings

Celia wrote: ...Gavin's email about CD-Rs came in with additional sporadic numbers and such
which made it hard to sort out.

This is an attempt to rectify this: here's the same message with the plain text switch set on, and all formatting removed explicitly. Hope it works. Gavin

This inquiry is a bit off topic for this list, but I imagine several of you have experience in the matter, especially those who are librarians. I am in the situation of recording cd-r images of a hard disk for deposit in a university archive, and I wonder what the latest information is on longevity and recording techniques. Is the general recommendation still the gold disks? Any brand preferences? Does recording speed have an effect? What lifetimes in controlled storage are to be expected? Are there studies available on the web?

I found a Kodak paper, Lifetime of KODAK Writable CD and Photo CD Media by Douglas Stinson, Fred Ameli, and Nick Zaino
Digital & Applied Imaging, ©1995 Eastman Kodak Company, which concludes "that with 95% confidence, 95% of the population of KODAK Writable CD Media will have a data lifetime of greater than 217 years if stored in the dark at 25°C, 40% Relative Humiditiy after being recorded in a KODAK PCD Writer 200. " They do not specify the brand of media better than this, and conclude that the claim for lifetime should be "greater than 100 years". They claim elsewhere that their latest best medium is the Kodak Ultima for which the claim for lifetime rises from about 100years to about 5000 years. This is a 24kt gold reflective layer cd-r.

"The table below shows the estimated lifetime for Kodak Ultima media at 30 C based on the choice of reported activation energy.

____________________________Source Media Activation Energy (eV)__Estimated lifetime (years)
Company A CD-ROM (aluminum)______________0.94________________________________9
Company B CD-R (silver)__________________1.65______________________________443
Kodak CD-R (gold)__________________________2.10____________________________5,083 "

If the table above is indecipherable, try changing to a monospace or teletype font.

In another Kodak online document, Type SA Media White Paper version 0.95, 06/12/01, 2, http://www.kodak.com/global/plugins/acrobat/en/service/cdrMedia/ultimaDesc.pdf, they show data for recording at various speeds which reveal no significant differences.

Can anyone top that?

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