Published on May 26th, 2017 | by Alan Cross1
Are Your CDs Rotting? You Might Want to Check on Them.
I’m finishing up a major home office move that included transferring close to 10,000 CDs from upstairs to their new storage spot in the basement. Even though I’ve always taken very good care of my collection (cool, dark place, never jamming them together too tight, etc.), I noticed that some of them don’t seem to be feeling so well. Discs that used to play just fine in every machine take longer to load. Some won’t load at all, no matter how much I clean them.
Prerecorded discs are generally fine, though there are a few that don’t seem to cooperate anymore. And plenty of my old compilations–the ones I burned for the car–seem to have died.
Something’s wrong. Back in the day, CDs were advertised as “perfect sound forever.” Turns out that when it comes to compact discs, “forever” can be defined as about 30 years–plus or minus a decade.
We’re only now discovering exactly how CDs degrade, rot and die. This is from The Atlantic.
[Fenella France, chief of preservation research and testing at the Library of Congress] and her colleagues are trying to figure out how CDs age so that we can better understand how to save them. This is a tricky business, in large part because manufacturers have changed their processes over the years but won’t say how. And so: we know a CD’s basic composition—there’s a plastic polycarbonate layer, a metal reflective layer with all the data in it, and then the coating on top—but it’s impossible to tell just from looking at a disc how it will age.
“We’re trying to predict, in terms of collections, which of the types of CDs are the discs most at risk,” France said. “The problem is, different manufacturers have different formulations so it’s quite complex in trying to figure out what exactly is happening because they’ve changed the formulation along the way and it’s proprietary information.”
Even CDs made by the same company in the same year and wrapped in identical packaging might have totally different lifespans.
Uh-oh. Better keep reading.