EEVblog Electronics Community Forum
General => General Technical Chat => Topic started by: Jan Audio on July 09, 2019, 12:52:45 pm
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Hi, i was searching about the lifespan of factory compact discs,
on wikipedia ( in dutch language ) i read this :
Vergankelijkheid
Ook het rechtop bewaren in een cd-doosje in plaats van liggend komt de levensduur ten goede
https://nl.wikipedia.org/wiki/Compact_disc
Translated :
Store your CDs standing, not laying flat, it improves lifespan.
I cant find anything about it in the english version.
Dont the electrons fall out ?, or is it a joke.
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CDs produced in series (not CD-R, which are engraved) are basically injection-molded/pressed polycarbonate, with a reflective layer of aluminum. Not sure what the joke about electrons is all about.
Both the polycarbonate and aluminum layer are not infinitely durable. They will degrade over time. I'm not sure why they would degrade faster while laying "flat", unless they are stored on top of one another (and not in their protective case), pressing onto the ones below... or would that be the effect of sheer gravity on the polycarbonate? ;D
The lifespan of series-produced CDs is said to be between 50 years and 200 years depending on the sources.
I'd suspect that UV light would accelerate degradation, so keeping the CDs out of sunlight would be a good start to maximize their durability. Speaking of that, the usual transparent CD cases are less than ideal, even with the paper covers.
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Thanks for reply
Some clown wrote that on wikipedia ?
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I don't know, there may be another reason to justify this I'm not aware of, but I can tell there are significant differences in this article in the various languages it's written in. I think Wikipedia should enforce stricter rules so that a given article reasonably gives the same level and quality of information in each language. It's not always the case, and I find this disturbing.
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OP, didn't feel like mentioning that the claim is referenced and backed up in the provided reference?
[9] https://web.archive.org/web/20120128065743/http://www.verbatim-europe.nl/nl_26/page_wat-is-de-gemiddelde-levensduur-van-een-standaard-cd-(industrieel-geperst-en-zelf-gebrand)-_220_4.html (https://web.archive.org/web/20120128065743/http://www.verbatim-europe.nl/nl_26/page_wat-is-de-gemiddelde-levensduur-van-een-standaard-cd-(industrieel-geperst-en-zelf-gebrand)-_220_4.html)
I'm not saying this makes it correct, but the real question here is whether there's a joker (or a scientist who's not aware of p-hacking) at www.verbatim-europe.nl (http://www.verbatim-europe.nl), not whether there's a joker on wikipedia.
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https://www.verbatim.com.au/media/brochureImage/brochurePdf/DVD-CD_Handling.pdf (https://www.verbatim.com.au/media/brochureImage/brochurePdf/DVD-CD_Handling.pdf)
DO
4. Store discs upright (book style) in plastic cases specified for CDs and DVDs
DO NOT
4. Store the discs horizontally for a long time (years).
Again, no hint what the underlying reasoning is, or whether it's even true, but Verbatim seem pretty keen on the idea.
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I don't speak dutch, but here is a translation from Google translate:
What is the average lifespan of a standard CD (industrially pressed and self-burned)?
Internal tests of the expected service life (in rooms with temperature control) have shown that a durability of approximately 100 years can be expected for both CDRs and DVDRs. This only applies if the discs are stored under certain circumstances. The original copy quality naturally also plays an important role. In that regard, there are preferred combinations for copy programs and media. The storage method also plays an important role (upright in a cdr or dvdr box, at a temperature of 20 - 25 ° C and a relative humidity of 55%, and protected against light, smoke-free, etc.).
Typically, any use of a cdr / dvdr shortens the service life since minor damage, such as scratches, fingerprints, dust and the like, is difficult to prevent. You can therefore extend the life of a disc by handling it with care. However, a specific lifespan cannot be promised due to the important role of the user.
Because we do not have test data, we cannot say anything about the lifespan of pressed CDs / DVDs. With a comparable production quality, however, they must last as long as writable media.
You'll see that 1/ there is no answer to the Op's question: they only talk about CD-R/DVD-R, and admit they have nothing to say about pressed CDs, and 2/ I haven't seen anything about storing the CDs flat or vertically... (they do talk about protecting them from light and that's pretty much what I said.)
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https://www.verbatim.com.au/media/brochureImage/brochurePdf/DVD-CD_Handling.pdf (https://www.verbatim.com.au/media/brochureImage/brochurePdf/DVD-CD_Handling.pdf)
Yes, this reference was not given in the dutch Wikipedia article though. And as I said, there are significant discrepancies depending on the language.
That said, I kinda remember this advice being given on CD-Rs packages back when I was still using them. I think this was pretty much what I hinted above, that is, avoid storing the CD-Rs laying flat WITHOUT any protective case (or with just a paper enveloppe, remember that many CD-Rs sold by 10 or more were sold without any hard case...) Which seems to make sense as the plastic used for CD-Rs (not sure it is polycarbonate) is much softer (and much more fragile) than what's used on pressed CDs. Storing CD-R laying horizontally but in hard cases should not make any difference IMO, as long as the engraved side is not directly touching anything, and Verbatim is not even explicit about that, but I'm pretty sure that's what they mean. Of course as I said above, maybe some physicist could enlighten us as to how gravity alone would degrade the surface faster if it's stored horizontally. I kinda doubt that, but hey.
Also again, this doesn't say anything about pressed CDs, as those Verbatim notes, AFAIK, are targetted at the recordable media, and not the industrially pressed ones.
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Ok, maybe they did not mention it applys to CDR only.
note : Verbatim is sold and is bad quality now a days.
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Ok, maybe they did not mention it applys to CDR only.
Verbatim did in their note though.
Now if this is indeed for the reason I'm suspecting (ie.: don't store your CDs laying flat DIRECTLY on their engraved/pressed surface, so that's not just a matter of being horizontal, but a matter of the surface directly touching another surface with some weight - its own or more if several are stacked), that sounds reasonable advice to me. But hard cases are made so the surface is not touching anything, so in hard cases, that shouldn't make a difference whether it's horizontal or vertical...
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Indeed the hard cases can build big towers.
case closed ?
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You could always ask Verbatim's support for more technical details about what they mean. I wouldn't expect more than a polite, "marketingly-correct" answer though. If you get any.
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For pressed CDs, the metalized aluminum layer is vulnerable through the thin labeling on top so pressure should not be applied there. DVDs are tougher in this respect because their pressed or written layers are embedded between layers of polycarbonate.