[LINK] "The Library of Congress Wants to Destroy Your Old CDs (For Science)"

[rfmcdonald]

Adrienne Lafrance's article in The Atlantic makes me think that I should back up my compact disc library immediately. The fragility of such a once-ubiquitous medium says worrisome things about the future of our cherished information. (Apparently, read/write discs are much worse.)

"All of the modern formats weren't really made to last a long period of time," said Fenella France, chief of preservation research and testing at the Library of Congress. "They were really more developed for mass production."

France 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. That's what Library of Congress researchers found when they tested twin copies of Paul Winter's Grammy-nominated 1987 album Earthbeat.

The two seemingly identical discs were exposed to extreme heat and humidity in an accelerated-aging machine. They cooked for about 500 hours at 175 degrees and in relative humidity of 70 percent—about what you'd expect on a sweltering July day in New York City, but not quite as humid as a rain forest. One of the CDs emerged relatively unscathed. The other was zapped of its musical data, completely destroyed by oxidation.