CD-R longevity

    **** Moderator's comments: The following appeared in book_Arts-L
    and is reproduced here with permission

    Date: 21 Jan 2004
    From: Gavin Stairs

    ... 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
    and Applied Imaging, (c) 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 deg. C, 40% Relative
    Humidity 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           Estimated
                                        Activation      lifetime
                                        Energy (eV)     (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"

    In another Kodak online document, Type SA Media White Paper
    version 0.95, 06/12/01, 2,

        <URL: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?

    **** Moderator's comments: The above URL has been wrapped for
    email. There should be no newline.

Teri L. Herbert


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                  Conservation DistList Instance 17:51
                Distributed: Thursday, January 29, 2004
                       Message Id: cdl-17-51-018
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