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...the previous link I originally posted is for subscribers only. The one listed above should work for non-subscribers, too. Nope, asked me to register.
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There was an article in one of the newspapers or magazines here in the UK recently on this subject. CD rot is only likely to affect CD-R discs....not normal CDs (unless they have some sort of manufacturing defect)or CD-RWs. There were a few 'experts' wheeled out who explained why this was; I can't remember the explanations now as I was only half interested. I do remember that one suggestion as to how to avoid it (other than not use CD-Rs in the first place) was to regularly copy any CD-Rs onto new discs etc which I guess isn't rocket science for anyone.
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Posted: |
May 7, 2004 - 3:04 PM
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By: |
w-dervish
(Member)
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YES, CDs can "rot". I registered, and grabbed the article. here it is: CD ROT SHOWS THAT DISCS AREN'T SO RELIABLE AFTER ALL. By Peter Svensson, The Associated Press. Thursday May 06, 2004. His music collection hasn't always been stored in the best conditions, Mark Irons of Corvallis, Ore., admits. But he's still dismayed by the deterioration of CDs such as this one. 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, would not 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 many 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 from 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, said 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. In Hartke's view, however, it is more common that discs are rendered unreadable through 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 is the clear underside of the CD that is most fragile, when in fact it is 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. 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. 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 who 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. For maximum longevity, discs should be stored vertically and handled only 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 is 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 has moved his discs to an apartment with a more stable temperature, he has 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. Caring for Discs Handling tips for CDs and DVDs from the National Institute of Standards and Technology: • Handle discs by the outer edge or the center hole. Your fingerprints may be acidic enough to damage the disc. • Use a felt-tip permanent marker to mark the label side of a CD. The marker should be water-based or alcohol-based. In general, these will be labeled "nontoxic". Stronger solvents may eat through the thin protective layer to the data. (this tip obviously referrs to CDRs -- although pressed disc CAN rot). • Keep discs clean. Wipe with cotton fabric in a straight line from the center of the disc toward the outer edge. If you wipe in a circle, any scratches may follow the tracks of the CD, rendering them unreadable. Use CD/DVD-cleaning detergent, isopropyl alcohol or methanol to remove stubborn dirt. • Return discs to their plastic cases immediately after use. • Store discs upright (book style) in their cases. • Store discs in a cool, dry, dark place with clean air.
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DRY LAND IS A MYTH!
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Those who deny the existing of CD rot, do you think the people who have had discs rot are lying? I think the misunderstood message is about the inevitability of CD rot, that it is a factor of age. I think that's incorrect. CD rot does happen but is normally due to flaws in the disc and is not an inevitability. Of course, the CD will be lost eventually. But I think most CDs will live up to their guarantee of lasting a long time. Cheers
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Posted: |
May 7, 2004 - 6:06 PM
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By: |
Krell
(Member)
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Interesting article, but does'nt take into account the age of the CD player the person in the article owned. Some CD's that refuse to play on my Denon portable ( purchased in 1989 ) play fine on a more recent vintage CD player ( 2000 ). That 'pinhole' effect, when a CD is viewed back lit ,has been around since the beginning, I can remember checking my CDs when I first read about it back in the mid 90's, along with darkening the edges of CDs with a green marker to reduce the pickup laser beam from 'leaking' out the edge of the disc and CD stabilizers ( remember those ! ). The pinholing is attributed to the fact that some CDs are plated heavier than others, I have some CDs that are virtually like mirror sunglasses, you can see thru them, they're plated so thinly. Even if there was CD rot, I don't think it would cause pinholes, when aluminum oxidizes it's dulls.
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"CD Rot" is definitely real, though it can of course be debated what causes it. However, I have over the years encountered an (admittedly very small) number of CDs that suffer from unexplainable deterioration over the years. And it can be "measured" (by re-ripping the CD every few years, for example). I've had CDs I ripped over 10 years ago which had a small number of sectors affected, and years later again and the number of sectors was significantly larger. (Despite the CD not being played in between an just sitting straight in the shelf.)
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Posted: |
Oct 28, 2024 - 11:30 AM
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By: |
Andy
(Member)
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most of my CD-R from 20 years ago are "dead". But to bring some fresh air in the old thread. i own a bigf DVD /Bluray collection too, an here rotting is very prominet of blurays too. nearly 20 blurays rooted away, not playable (mostly manufactured 2008-2011) e.g. Cowboys and Aliens, Kings Speech, El Cid, Fall of the Roman Empire, Inglorious Basterds, Jaws, Alexander, The Pianist, Centurion, Becket, Pandorum)
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Posted: |
Oct 28, 2024 - 11:35 AM
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By: |
Thor
(Member)
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most of my CD-R from 20 years ago are "dead". But to bring some fresh air in the old thread. i own a bigf DVD /Bluray collection too, an here rotting is very prominet of blurays too. nearly 20 blurays rooted away, not playable (mostly manufactured 2008-2011) e.g. Cowboys and Aliens, Kings Speech, El Cid, Fall of the Roman Empire, Inglorious Basterds, Jaws, Alexander, The Pianist, Centurion, Becket, Pandorum) That's what you get from storing them in your aquarium of sulfuric acid all these years.
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most of my CD-R from 20 years ago are "dead". But to bring some fresh air in the old thread. i own a bigf DVD /Bluray collection too, an here rotting is very prominet of blurays too. nearly 20 blurays rooted away, not playable (mostly manufactured 2008-2011) e.g. Cowboys and Aliens, Kings Speech, El Cid, Fall of the Roman Empire, Inglorious Basterds, Jaws, Alexander, The Pianist, Centurion, Becket, Pandorum) That's what you get from storing them in your aquarium of sulfuric acid all these years. Hahaha.
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A random reply 20 years later, or was there something that spurred this, Nicolai? No, not entirely random. :-) There was indeed something that spurred this. Since you asked (I just give the extra short version): I accidentally came across some weird errors while ripping a set of new Chandos CDs I just ordered (everything turned out fine in the end, by the way), so I decided to check with some other CDs that showed some strange errors when I ripped them years ago. And I re-ripped them. I noticed that the error rate in some (two) of these CDs since then has increased considerably, even though they were kept well, have no visible scratches, were just sitting in the jewel case in the shelf since the last time I took them out.
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