You have been told so repeatedly (I even wrote in 2007 an article about the weaknesses of CD/DVD, a few years ago already), it is mentioned again in an article about backups for the photographers, but there are still some people to believe that the CD or the DVD is a good solution to the archival problem of digital photographic pictures.
This is all wrong: CD and DVD are optical devices whose shelf life has nothing to do with the century some would believe is the credible target. Even in the best storage conditions.
You don’t believe me? The French Laboratoire national de métrologie et d’essais (LNE) just presented to the French Académie des Sciences a very detailed report about this issue. They worked on the recordable optical media and their conclusion is strong:
The storage or the the short-term backup do not bring any significant question, but building decade-long or century-long archives this way is an altogether different issue, understanding that these digital media have no more than a lifetime of 5 or 10 years.
Then:
If this problem is correctly handled in some specialized public organizations, it is widely ignored by the public and most of the institutions or enterprises. A large quantity of personal, medical, scientific, technical, administrative data is thus in really endangered.
So you still doubt it? Your photos are still on a DVD?
See also: Backup solutions for the photographers.