Hi Tom/Wayne
>> Doubt what you want, but good CD plastic, properly stored, has a two
>> century life. It is inherently more stable chemically than film,
>> especially colour, negative or positive.
Most CDR's you buy at the supermarket, corner computer store,
have an expected lifetime of 10 years. As Wayne has pointed out
most CDR's use a dye system, the earlier ones used a dye that
was heated up by the laser to "blow" a pit in the aluminium surface.
Modern cheapy CDWriters use the heat to disfigure the dye, so
that the light is not completely reflected back, giving you a digital
1 or a digital 0.
I bought some EMTEC CDR's a few weeks ago, with the BASF
logo on them, using CDRecord I've noticed they have the code
for a manufactorer that became defunct a few years ago, I'm glad
I only bought these for a one demo distribution.
Even for audio recordings, these cheap CD's are showing problems
with playback on some Audio CD Players that play store bought CD's
with no problems.
Not also that some DVD players cannot play music CDR's, and specify
such on the box, not due to copywrite but due to the players are so cheap
they do not have the optics to correctly pickup the laser density caused
by the dyes.
If you buy the top quality Kodak/Sony CDR's, with perfect storage
you might be able to read them in 100 years time but you will also
notice the Guarentee seems to be changing :-)
CDR's can also fall victim to fungus which eats through the silver
backing, the glue/process used to adhere the lining onto the CDR
also has a limited life of 10 years.
If you want to store CDR's for use in 100 years time or longer,
you would need a dry, temperature and pressure regulated
enviroment, and completely dark, preferably nitrogen filled.
I remember the old RetraVision ad's for CD's when they were
first sold in Australia in the early 80's "Indestructable" phewt....
CD's are a lot more rugged than CDR's, think about it :-)
Cheers
Ian Manners
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