The darker the media the faster it tends to die. I have CD-ROMs going back to the very early days of CDs. They tend to survive longer than DVDs burned later.
I have been copying all my CD-ROMS and burned DVDs to hard drives. (BTRFS with file duplication.)
Different dyes. The darkness of the dye isn’t actually relevant, it’s how UV reactive it is.
Cyanine dye is very unstable in UV light. Phthalocyanine dye is relatively stable, but needs a good quality drive to burn an archive quality disc, and Azo dye is even more stable.
Different disc manufacturers are also of varying quality, and the brand of the disc is not always the same as the manufacturer.
You see those dystopian SF stories about all human knowledge lost and you think “how could have happened”. This is how it happens.
And I can personally say that I have a few CD’s from the 80’s (Dog Eat Dog by Joni Mitchell) that are unplayable due to rot…that one you can actually see a hole in the foil.
I suspect there is evidence to suggest that storing CDs on a spindle will submit them to uneven pressures and cause warping, whereas a CD stored in a case, clamped solely at its center, may have greater longevity. Adhesive labels can cause similar problems, apparently.
[quote=“SamWinston, post:45, topic:96810”]You see those dystopian SF stories about all human knowledge lost and you think “how could have happened”. This is how it happens.[/quote]I quite like this one, personally: http://trillian.mit.edu/~jc/humor/Ms_fnd_in_a_Lbry.html
i know right? all my discs had holes in the middle!
the failure rate did subjectively seem higher then my binders, but even those were abysmal.
to be fair, i typically would buy cases of whatever 100 disc spindles were on sale at the time, the cheap stuff seems especially bad, up to 90% failure rate on 10 yr old discs.
discs stored in the dark seem to fair a bit better. there seems to be some light, if i had to guess uv, degradation around the outsides of discs stored in spindles.
ironically i recently pulled data off of some 3.5 hd floppies twice that age and they were mostly fine, a few places required multiple passes to read, but as far as i can tell the data is intact.
Enduring is one thing. Retaining meaning is quite another. There’s something to be said for rotting as a transition to something potentially better. Or so one might infer from the classic archaeology parody Motel of the Mysteries.