CDs and DVDs Not So Immortal After All

[BJ_M]

http://apnews.excite.com/article/20040505/D82CIN9G0.html


Dan Koster was unpacking some of his more than 2,000 CDs after a move when he noticed something strange. Some of the discs, which he always took good care of, wouldn't play properly.

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.

Part of the problem is that most people believe that it's the clear underside of the CD that is fragile, when in fact it's the side with the label. Scratches on the underside have to be fairly deep to cause skipping, while scratches on the top can easily penetrate to the aluminum layer. Even the pressure of a pen on the label side can dent the aluminum, rendering the CD unreadable.

Koster has taken to copying his CDs on his computer to extend the life of the recordings. Unfortunately, it's not easy to figure out how long those recordable CDs will work.

Fred Byers, an information technology specialist at the National Institute of Standards and Technology, has looked at writeable CDs on behalf of government agencies, including the Library of Congress, that need to know how long their discs will last.

Manufacturers cite lifespans up to 100 years, but without a standardized test, it's very hard to evaluate their claims, Byers says. The worst part is that manufacturers frequently change the materials and manufacturing methods without notifying users.




"When you go to a store and buy a DVD-R, and this goes for CD-R as well, you really don't know what you're getting," he says. "If you buy a particular brand of disc, and then get the same disc and brand six months later, it can be very different."

This renders the frequently heard advice to buy name-brand discs for maximum longevity fairly moot, he says.

DVDs are a bit tougher than CDs in the sense that the data layer (or layers - some discs have two) is sandwiched in the middle of the disc between two layers of plastic. But this structure causes problems of its own, especially in early DVDs. The glue that holds the layers together can lose its grip, making the disc unreadable at least in parts.

Users that bend a DVD to remove it from a hard-gripping case are practically begging for this problem, because flexing the disc puts strain on the glue.

Rewriteable CDs and DVDs, as opposed to write-once discs, should not be used for long-term storage because they contain a heat-sensitive layer that decays much faster than the metal layers of other discs.

For maximum longevity, discs should be stored vertically and only be handled by the edges. Don't stick labels on them, and in the case of write-once CDs, don't write on them with anything but soft water-based or alcohol-based markers.

Also, like wine, discs should be stored in a cool, dry place. Koster's friend Mark Irons, of Corvallis, Ore., stored his CD collection in a cabin heated by a wood-burning stove. The temperature would range between 40 degrees and 70 degrees in the space of a few hours. Now, the data layer of some of his CDs looks as if it's being eaten from the outside.

Irons is still pretty happy with CD technology, since it beats vinyl LPs and tape for longevity. Now that he's moved his discs to an apartment with a more stable temperature, he's noticed that the decay has slowed.

"I'm hoping they'll hold out till that next medium gets popular, and everyone gets to buy everything over again," he says.

[BJ_M]

dosn't look like rot to me -- looks more like cheap disks

[teegee420]

No kidding. Get discs with frosted or painted tops, or put a label on it(CD's) you cheap bastard.

[adam]

Judging from that guy's picture, my guess is that he accidentally tried to smoke them.

[SLK001]

Too much cannabis smoke, I'm presuming. Anyway, this is an old, known problem. This is the reason that DVD's have better protection of their aluminum layer.

[flaninacupboard]

dunno about the picture, can't tell if that's a pressed disc or a CD-R.

however, laser rot is nothing new, i've got a few laserdiscs which have become awful to watch. i even found a website discussing it showing up on DVD's, and i've had to return several dual layer dvd's that were visibly badly bonded as i know they'll rot in no time. i've had CD-Rs that had discoloured spots form on them and become unplayble. they were kept underground in a moderately humid but cool environment.

optical media just seem doomed.

[Josef K]

Whoa! Something nasty is growing off that. And the CD doesn't look too healthy, either.

It's that same old problem, though. You never can tell how long anything will last until it lasts long enough for you to know.

[FulciLives]

You never can tell how long anything will last until it lasts long enough for you to know.

... and of course by then ... it is too late!

- John "FulciLives" Coleman

[WeedVender]

I have that same problem with my CDRWs... they are supposedly Sony CDRW but they SUCK ! I bought a 25 pack a while ago and wasnt impressed at all... But going back to the CDRWs, I have the same thing on the other layer and ive been noticing the same thing on my TDK cdrs but not to that extent..I believe it was caused by the heat of the sun on the crate that they used to transfer all my stuff when I moved and inside, under serveral heating blankets and beach towels was my CD stash... and they were just thrown in there no Jewel case or stack method. I have to say that up to this point... TDK is an EXTREMELY good brand... who knows if they will turn to crap....

[Capmaster]

http://www.gcn.com/23_5/news/25166-1.html

According to this there is evidence that our recordables might just outlast the pressed commercial DVDs and CDs. They're saying 100 - 200 years is possible Provided you don't use it as a hotpad or as a real coaster

[BJ_M]

thats a good thing about printable cdr's they have good back surface protection ...

[BJ_M]

Judging from that guy's picture, my guess is that he accidentally tried to smoke them.

there is a lot of green leafy mater in the background to be sure ...

plus isnt it ileagal in the USA to back up your cds anyway ?

so whats with all the pill bottles near the stack of blanks ?

looks like he is RIPPING dvd's also !!!

[axolotls]

We were all told that CDs were well-nigh indestructible when they were introduced in the mid '80s,"

how optimistic... i thought them people ?'d authority... man.....

[teegee420]

Exactly. This is probably the same generation that believed life by now would be just like as depcted on the Jetsons. I'm still waiting on my Food-a-rac-a-cycle.

[VCDHunter]

http://www.gcn.com/23_5/news/25166-1.html

According to this there is evidence that our recordables might just outlast the pressed commercial DVDs and CDs. They're saying 100 - 200 years is possible Provided you don't use it as a hotpad or as a real coaster

100 years ! Well that beats vinyl hands down or should that be pants down Cap ??

[Capmaster]

http://www.gcn.com/23_5/news/25166-1.html

According to this there is evidence that our recordables might just outlast the pressed commercial DVDs and CDs. They're saying 100 - 200 years is possible Provided you don't use it as a hotpad or as a real coaster

100 years ! Well that beats vinyl hands down or should that be pants down Cap ??

Depends on what the hand is on

[Oscar wallace]

Anybody know how to burn a 2 hour film into a stone tablet?...Well at least we know they last at least 3000 years

[Capmaster]

Anybody know how to burn a 2 hour film into a stone tablet?...Well at least we know they last at least 3000 years

The big problem with stone is interlacing

[somebodeez]

Part of the problem is that most people believe that it's the clear underside of the CD that is fragile, when in fact it's the side with the label. Scratches on the underside have to be fairly deep to cause skipping, while scratches on the top can easily penetrate to the aluminum layer. Even the pressure of a pen on the label side can dent the aluminum, rendering the CD unreadable.

In this case wouldn't labels help protect CDs?

[MeTaLgEaRsOoTy]

yeah,but i wonder what size of burner would have been needed for burning those stone babies..maybe thats what the pyramid tops were for,and thats why there worn down now.
and stonehenge is an ancient record player with multiple needles.

if you want to see a cd rot quick,stick it in a dish with some pepsi,or coca-cola..thatll do the business.

[raffie]

Anybody know how to burn a 2 hour film into a stone tablet?...Well at least we know they last at least 3000 years

and

The big problem with stone is interlacing

what kind of drive do you use for stone tablets anyway?

[JimJohnD]

Why a "HARD" drive, of course.

[Capmaster]

Why a "HARD" drive, of course.

[Snakebyte1]

What format of stone tablet has the most compatibility? Granite or Marble

[smearbrick1]

When this guy was "moving", where did he store this stuff before he unpacked it? I think anything will rot if subjected to enough heat and moisture. Probably had it sitting under a carport or something. Maybe stored in a dank, damp basement. For christ's sake mister, buy some better cd-rs and not something without a protective layer!!!

...also, have a visit to the barber.

[ROBERT BLACK]

I'm willing to bet he stored his cd-rs in the hothouse where he keeps his plants. Any takers?

[triphop]

LOOK!!! Its Jesus!

[Roderz]

Dan Koster was unpacking .......

[flaninacupboard]

i don't have the beard but my hair is as long as that...

i sometimes get called jeezy creezy.

[offline]

Laser rot.. blah.

Try K. I. D. S.

for thermonuclear results try R.E.L.A.T.I.V.E.S

(for capmaster)

V.Y.N.A.L