CD Labels and Archival Longevity
Victor Odhner
vodhner at cox.net
Tue Jul 26 08:08:25 MST 2005
Spinning off from the CD labels topic.
I recently did some Google research on CDs and archival longevity.
Some things I learned:
* CDs that are "pressed" commercially are recorded by a different
process and last much longer, are more resistant to heat, etc.
I don't know what the minimum quantity is to get these recorded.
* Burn'em'yourself CDs do their recording just behind the label side,
and the sticky labels definitely can cause damage leading to oxidation
in the recording media, corrupting the data. It is recommended to
use a sharpie marker on the very outer edge, or around the hub,
where there is no recording surface. There are pens sold for
labeling of CDs, but nobody seems to know if they are any safer.
* CDRs made in Japan are the best of the normal run -- all produced
by the same company -- but you can get CDRs from Colorado using
Gold-on-Gold media for about $1.50 each that are the very best.
* CDRs are very sensitive to heat, UV and -- excessive moisture.
That was a surprise to me. Apparently the plastic is somewhat
hydrophilic. Probably not an issue for us around here, except
maybe where an evaporative cooler is used throughout the
monsoon season.
* While the worst CDRs can lose their minds within months, we
should remember that the whole CD technology will be obsolete
in just a few years, so actual archival CDs will go the way of the
JPL tapes before they are likely to go bad.
I should add that my wife carries some CDRs in her car, which
sits out in the sun, and sometimes the discs are kicking around on
the floor or in direct sunlight on the seats; yet they are mostly
working fine after 1-2 years of this. These things are pretty darn
rugged. Just keep a backup. ;-)
Vic
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