CDs and DVDs Very Mortal
Published May 07, 2004
Lesson: never be an early adopter. I didn't start accumulating CDs until 1990 and so far mine are holding up fine. Of course, I also store and handle mine properly, not to say anal-retentively, so that probably makes a difference:
Koster, a Web and graphic designer for Queens University of Charlotte, N.C., took one that was skipping pretty badly and held it up to the light.
"I was kind of shocked to see a constellation of pinpricks, little points where the light was coming through the aluminum layer," he says.
His collection was suffering from "CD rot," a gradual deterioration of the data-carrying layer. It's not known for sure how common the blight is, but it's just one of a number of reasons that optical discs, including DVDs, may be a lot less long-lived than first thought.
"We were all told that CDs were well-nigh indestructible when they were introduced in the mid '80s," Koster says. "Companies used that in part to justify the higher price of CDs as well."
He went through his collection and found that 15 percent to 20 percent of the discs, most of which were produced in the '80s, were "rotted" to some extent.
The rotting can be due to poor manufacturing, according to Jerry Hartke, who runs Media Sciences Inc., a Marlborough, Mass., laboratory that tests CDs.
The aluminum layer that reflects the light of the player's laser is separated from the CD label by a thin layer of lacquer. If the manufacturer applied the lacquer improperly, air can penetrate to oxidize the aluminum, eating it up much like iron rusts in air.
But in Hartke's view, it's more common that discs are rendered unreadable by poor handling by the owner.
"If people treat these discs rather harshly, or stack them, or allow them to rub against each other, this very fragile protective layer can be disturbed, allowing the atmosphere to interact with that aluminum," he says.
- CDs and DVDs Very Mortal
- Published: May 07, 2004
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- Section: Sci/Tech
- Filed Under: Music: News, Video: News
- Writer: Eric Olsen
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Comments on this articleComments
I've got CDs that are 17 years old and show absolutely no signs of this "rot" that he describes. I take great care of my discs, too, so I think that's the deciding factor. If you treat them like coasters, that's exactly what they will be one day. Treat them like you would vinyl and they'll last you forever. I never once believe the "indestructible" claims everyone else cites - we all know from the Titanic tragedy what happens when you boast how "indestructible" something is, don't we?
i have one CD that has become unplayable.
my copy of Marc Ribot's "Rootless Cosmopolitans" has more than just pinholes in it...the manufacturing process must have been bad because the hole are pretty big, like a couple of millimeters or so.
Tom: While poor treatment can clearly lead to problems, I don't think it will lead to the pinhole problems described. That seems simply to be a manufacturing defect, and I've got friends who treat their CDs very well indeed who have had one or two go south over time.
What we need are laser-readers for vinyl, so that the vinyl never wears down!
I've got a few CDs that wound up with holes in them because they unfortunately fell, were scraped, etc., and those have problems - but the problems are all due to those holes through the top layer.
I would urge anyone who uses those Case Logic notebook cases to be VERY careful - most of the CDs that I've had that had problems were stored in those cases. The problem with them is that while they protect the back side of the disc (non-label side) they don't protect the most fragile part, the layer under the label. The sleeves, as well as other CDs that face them on the opposite page rub against the thin coating over the aluminum reflective layer and slowly wear it away. Believe me - I have seen this on multiple discs, and I was able to confirm this several times. Those notebooks with sleeves are bad news for CDs. Had they a hard-cover that prevented flexing and crushing, they probably would have been fine. I lost some good discs that way.
Great points all - thanks!
can you tell me why these materials were chosen when first making dvds? i am doing a project for school about dvds and i would like to know so can you tell me i mean if you know
-thanks-
Tiffany, the clear material is polycarbonate, chosen probably because it's relatively strong, cheap, and light. The reflective layer is usually aluminum, but can be other metals like gold, too - it just needs to be reflective, so you'll see black discs being used as well (found especially in gaming devices.)
You may want to refer to the "freaks" over at CD Freaks for more info. Someone in the forums there will probably know a lot more about this subject than you're likely to find actually documented in layman's terms on the internet. Good luck!
thanks Tom, excellent info and suggestion
A great place to look for DVD related products and information. For all your dvd needs.
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Also, adverse changes in temperature in the area where you store CDs can cause them to deterioate, i believe.