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Do audio compact disks deteriorate or have data loss? A catalog of archival storage materials (acid-free photo albums, storage boxes, etc.) makes the claim that CDs can corrode in the polystyrene jewel boxes supplied by most record companies, and that polypropylene ("milky" plastic) jewel boxes or special corrosion resistant inserts should be used in exsisting jewel boxes.

Is there anything to this, or is it all just a load of puckey?

[ July 05, 2001: Message edited by: MacDuff ]

As far as I know all CDs deteriorate over time from the simple wear and tear involved in using them. Eventually data will be lost but the advantages of digital data are that small mistakes are "recoverable" (CDs use very sophisticated error correction codes as the pressing process is not hugely accurate)
and you can always make perfect copies of your CDs as back ups. As long as you do that, at least in theory, you are statistically highly unlucky to lose data.

How long a CD will last with "normal" usage I'm afraid I don't know (it depends on the quality of the CD itself).

As to a chemical reaction with the case, I can't imagine this is terribly significant, but in all honesty I don't really know

[ July 05, 2001: Message edited by: Diarmuid ]

I've never heard of that chemical reaction, I'm somewhat skeptical about it. I've never seen or heard of a CD becoming defunct from that cause. The plastic itself should probably last longer that most of our bloodlines . When it sits in a normal jewel case I think the only part of it that has contact is the inner part of the hole.

As far as wearing out from normal use, there should be no wear at all. There is no contact or friction with any part of the cd while it is working except for it being held by the central hole. Scratches can accumulate over time from careless handling, but these can be taken out. They offer for sale kits to do this, I imagine it's not too different from the stuff to take scratches out of motorcycle helmet face shields. The part that actually stores the data is a sort of metallic foil disc that is embedded in the plastic, towards the top of the CD. I have seen an istance of this foil getting gouged from the top, I don't even want to KNOW how that one happened. That CD is cooked, or at least the f- nocturne of Chopin is.

[ July 06, 2001: Message edited by: Joe ]

Joe I know that CDs aren't touched when being read by a laser, I was referring to the normal, unavoidable and realistic wear and tear whilst being handled over the course of many years. CD companies have more or less admitted to this.

And yes the "other" side (the side with the printed stuff) is the worst place to scratch!

D:
What do you mean by "realistic wear and tear"? When I take a CD out of the jewel case, I handle it as recommended by the edges and centre hole, only, and similarly when I put it back. I don't leave them out of their cases when they are not in the CD player, nor do I use them as coasters for my hot chocolate in the winter. Where is there wear and tear in this process?

Several years ago - it may be as many as ten - either Chandos or Hyperion had a notice on their website about the potential for deterioration of the plastic sealant or coating used to protect their CDs. In that generation of CDs, the deterioration was, according to the manufacturer, visible in the form of discoloration. The coating, instead of remaning clear, tended to discolor. The manufacturer offered to replace - free of charge, of course - any CD that was subject to this deterioration and that subsequently failed to play.
I have several Chandos CDs of that vintage that have turned decided brown around the edges. However, they continue to play, and I have not been concerned about them.
I haven't recently checked the web site to see it that announcement is still there.
Regards,

Bravo Bruce, you are most carefull and diligent, and providing you always stick to such a perfect routine you'll be fine.

However, bear in mind that most (non jewel!)CD cases are not ideal and can contact the face of the CD. The face of the CD can come into contact with the CD tray when it is initially put into some players. Even you might drop one once in a while. Someone else might handle it incorrectly e.t.c e.t.c e.t.c and unless the chemical coating on them is completely inert it will degrade over time simply from contact with the air! (perhaps we should keep them in a vacuum?).

p.s. I don't use them as hot chocolate coasters either

if the coating is made of any up-to-the-standard plastic it should not degrade when in contact with air right? plastics are the things that when buried in the ground will remain around for hundreds of years... the only way to destroy them quickly is by burning... am i right on this?

http://www.hyperion-records.co.uk/bronzed.html

This URL will take you to Hyperion's web site where the deterioration I referred to is discussed at some length.

The discussion refers as well to CDs manufactured under the following labels: ASV, Unicorn-Kanchana, Pearl, DGG, IMP, Decca and Collins; with DGG and Decca (London) showing up on this list, we might be concerned for some older CDs in our collections.

Regards

[ July 06, 2001: Message edited by: BruceD ]

[ July 06, 2001: Message edited by: BruceD ]

My sarcasm was lost on you Magnesium (even with the vacuum comment!).

Yes they will degrade (very slowly) on contact with the air (some oxidation? and friction?) and yes it will take an extremely long time (and remember too that underground they will have less contact with air!).

[ July 06, 2001: Message edited by: Diarmuid ]

sorry... haven't been thinking properly lately... if i ever was thinking properly anyway... =]... have been studying intensively for exams at school... but now it's over!! yay! =]

[ July 06, 2001: Message edited by: magnezium ]