There was a report published by National Institute of Standards and Technology concerning longevity of CD/DVD media

http://www.itl.nist.gov/div895/gipwog/StabilityStudy.pdf

Basically, longevity derives from the use of cyanine dyes, as employed in Mitsui (rebraded as Delkin) and Taiyo Yuden blanks.

There are also fewer write errors from the get-go with good cyanine blanks. Slow record speeds (2X-8X) also help in this regard.

Coatings for mechanical durability and oxidation characteristics of metal alloys also come into play.

And, of course, storage conditions are key!!

I got my recommendation for Taiyo Yuden from a very senior design engineer for a major European corporation who has access to corporate lab test data. He suggested that Taiyo Yuden and Mitsui were more or less equivalent quality for consumer use. 

He was using numbers like 15-20 years, not "300 years" as Delkin likes to claim.

Most of the so-called data on media lifespan comes from the disc manufacturers themselves, so caveat emptor...remember Sony's marketing cry when CDs first came out: "Perfect sound forever"

Joe Roberts
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