General discussion

1/27/06 How long do burned CD-Rs and CD-RWs last?

Jan 25, 2006 9:54AM PST
Question:

I recently read an article by a data storage expert who claimed that burned CD-Rs and CD-RWs can be expected to last only two to five years and not a whole lot more. I personally have commercially pressed CDs from the 1980s that still play fine, but I have begun to notice that some of my burned CD-Rs are beginning to skip, or not start (player shows "no disc"), or have a strange echo that was not on the original. This sounds serious! The expert suggests that for secure long-term storage, high -quality magnetic tape is the way to go. Are any of your readers beginning to notice this problem with their burned CDs, and are there other opinions about how to combat it? Are some burnable CDs of higher quality than others? What are the best storage methods for the discs that will make them last longest?

Submitted by: Carl N. of Cottonwood, Arizona

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Answer:


Factory-pressed CDs are totally different from recordable CDs. In a pressed CD, the data is literally "molded into" (actually pressed into) the media and will not disappear unless the CD is physically damaged. Recordable CDs use a dye that changes color or reflectivity when heated. There are different dye types commonly used in recordable CDs--phthalocyanine, azo, and cyanine, in particular--and they do not all have the same life expectancy and stability.

All of the studies that I have seen except one suggest that properly burned one-time media (-R media, but not -RW media; see below) has an expected life of decades to possibly even centuries. There was a study by NIST (a U.S. government agency, used to be the National Bureau of Standards) on the relative stability of different media here:

http://www.itl.nist.gov/div895/gipwog/StabilityStudy.pdf

You can see some comparisons in the NIST study of the different dye types. But this study did not attempt to extrapolate the data to a life expectancy, although it did provide data about the relative stability of the different dyes and reflection layers behind them.

However, opinions still differ as to how long such media will last. The OSTA (Optical Storage Technology Association), in a report here:

http://www.osta.org/technology/cdqa13.htm

suggests that optical recordable media will last 50 to 200 years. This observation is backed by quite a number of studies that I have seen done both by the media makers and others. However, some storage experts suggest numbers more in line with your question, for example the expert in this report suggests a life of only 2 to 5 years:

http://blog.eogn.com/eastmans_online_genealogy/2006/01/life_expectancy.html (I have a suspicion that this is the article that you read).

The bottom line is that you are not going to get one single answer that everyone agrees on, although I personally am confident that properly recorded CD-R media can last decades if not a century or two. These 3 articles provide a good starting point for understanding some of the variables involved, which include:

-Dye type
-Physical construction of the media
-Storage conditions (temperature, humidity, light exposure, mechanical stress, chemical exposure and air quality)
-Manufacturing conditions (can vary from batch to batch in otherwise identical media of the same brand)

Now let?s mention some other things that are relevant and important:

-The quality of the burner. A borderline defective burner can ?under expose? the media to the laser beam, producing a seemingly good recording (at the time of burning) that will ?fade? over time (failing weeks, months, years or decades sooner than it should have had the laser beam intensity been correct)
-Recording speed. Fast burns (52X) are probably less stable than somewhat slower burns (say 16x to 32x), but you can burn media too slowly also. There is a very good analogy here to photographic film and exposure levels. The dyes on a given media have a certain range of acceptable ?exposures? and outside of that range, you can either under or over expose the media to the laser beam. However, mechanical jitter and certain other variables (largely a function of the quality of the drive) generally will be unconditionally worse at faster speeds.
-Your own handling and storage practices. On a CD, the data ?exists? in a dye layer on the label side of the media. This can be scratched from the back (from the label side), which will literally and directly destroy the data. The front side is clear plastic but can also be scratched. While front side damage may make the data less readable or completely unreadable, the data is still intact and undamaged on the label side, and the scratches on the front can normally be removed by polishing the plastic. On recordable DVDs, the data is on a layer ?inside? the media, but the media is a laminate of several layers and can delaminate, destroying the data. Flexing ? even VERY minor flexing ? is particularly bad at causing such damage. And, also, recordable DVDs tend to fail from the outside in, so you can increase your success rate and decrease the incidence of failures by not recording such media beyond 80% to 90% of capacity, leaving the outside edge, where the failure rate is greatest and failure occurs first, blank anyway.

-Labeling: The glues in adhesive labels, or the solvents in pen-type markers, both applied to the label side (the side containing the data) can SLOWLY penetrate the reflective backing and dye layers and destroy the data. Therefore, for archival media, the safest policy is to not label the CD or DVD itself at all. If you do label it, with either a label or a pen, you are, at best, taking a chance with your data (hint: it is safe to write on the clear inner hub (where there is no data at all) with a suitable pen that won?t rub off).

And, finally, I would be remiss if I did not mention one other factor which is really huge: Eraseable ?RW? media is FAR less stable than one-time (?R?) media and should absolutely not be used for any permanent recordings of any kind whatsoever. There is no question that RW media can and does ?fade?. Although I?ve never seen failure of ?R? media that I could attribute with absolute certainty to dye instability, I routinely see ?RW? recordings that are unreadable after periods of months to a year or two when there is really no other explanation for the failure. I see this both on CD-RW and DVD+/-RW media, and I advise people in the strongest possible terms not to use ?RW? media for anything that they want to consider permanent. Since RW media is also both more expensive (a lot more expensive) and slower, from my perspective the decision to never even buy RW media at all is an easy one from my perspective.

Submitted by: Barry W. of North Canton, OH

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Comments
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CD - Rs and Photos
Jan 26, 2006 11:06PM PST

Does this apply to photos?

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I have over 4000 cd-r's of legal live music - read my advice
Jan 26, 2006 11:07PM PST

I have been recording legal live music to CD-R for 4-5 yrs. now (Phish, Grateful Dead, etc), after switching from analog cassette tape. So the longevity of my collection is of extreme importance to me. Here is what I post on my website:

--I don't accept Taiwanese Fujis (very common nowadays), Memorex, Imation, Maxell, TDK's, Sony, or any generics in TRADES. I will accept Verbatim, Japanese Fujis, Mitsui, Kodak Gold, and Taiyo Yuden's. For the MOST PART, I've learned the general rule of thumb, is to only use discs made in Japan. Anything else just doesn't cut it. Discs made in Taiwan use cheaper dye that deteriorates much more quickly than the dyes used to make Japanese discs (again, for the most part!). I use most of these brands at different times -- mainly Japanese Fujis. Again, I've found the consensus criterion of what discs not to use are any discs manufactured outside of Japan.

--For labeling, you should NEVER write on the printed, data portion of the disc. Rather, ONLY write on the clear inner ring in the middle of the disc. This part of the disc does not contain any data. I recommend using a Sharpie Ultra Fine Point black marker.

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if i were you...
Jan 29, 2006 4:06AM PST

i would record all those CD-Rs to metal cassette tapes , just in case. keep the CDs..but if they decide to go south ,youl still have the tapes.

we KNOW tapes last atleast 30 years...(i have tapes that are 30YO and are fine anyway) CDs and especialy recordable CDs ,we just dont know.

or if you want to keep them digital, i would invest in 1 or 2 large hard drives (in the 400GB range) and rip all your CDs to them and store them as lossless FLAC or APE files. and then if your reely anal...copy that drive to an identical one or even set up a RAID, then you have 2 copys (3 if you count the origanal CDs)and the possibility of losing ther songs to a mechanical HDD failure will be virtualy non existant.

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The real question is...
Jan 26, 2006 11:16PM PST

I have a room full of backup tapes from the past decade. There is no equipment that can read the tapes, since the technology out ran it.

The CD/DVD burners today will also be left behind, and what do you have? Pretty little circles of plastic coasters for your drinking pleasure.

The real question is what are you going to use to read that disk 10 years from now? The operating system will change, your software will change and you will be on your 4th new computer, with all the "current" whiz-bang technology, which will not be able to access those beer coasters.

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Magnetic Media Instabilities
Jan 26, 2006 11:31PM PST

I'm not so sure about tapes either. I've been working with computer systems for 20 years now and have seen tapes fail (non mechanical) in 3-5 years as well. The media being used was not cheap run-of-the mill stuff. The usual rules of keep in a cool place, retension, etc. were followed but I learned that if it was really important, you probably should have two tape copies of it as one of them was guaranteed to have a read failure if you really needed the data.

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CDR Types
Jan 26, 2006 11:36PM PST

Do you have a preferance to any brand of CDR's for longer lasting or more stability?

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Please clarify -- "label side"
Jan 27, 2006 12:11AM PST

In Barry W.'s reply, he stated:

"-Labeling: The glues in adhesive labels, or the solvents in pen-type markers, both applied to the label side (the side containing the data) can SLOWLY penetrate the reflective backing and dye layers and destroy the data."

Was that a missprint? "the side containing the data"?? I generally don't consider the label side to be the side that contains the data. I can only guess that he means that "the label side (the side not containing the data) can SLOWLY penetrate . . . "

Otherwise, I see no reason to mention a problem with labels -- I don't know anyone who would mark the data side.

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Re: Please clarify -- "label side"
Jan 27, 2006 12:48AM PST

I think the reference was to the way a disc is built: the underside of the disc is thick plastic but the label side has a reflective coating just under the surface, into which the data is written. It's the side which is most easily damaged which is why it's not a good idea to write or stick things on it.

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Try scratching it off . . . .
Jan 27, 2006 1:13AM PST

The back of the "lable side" is where the data is written, and if you have a CD you don't want, just use a key, coin, or knife to scratch it off (or bend it) and you will see it flakes off with a shiny back like mirror backing -- then when you look at it you only have a clear plastic disk in that area. The data went "bye-bye" with the reflective coating from the "back", "top" or whatever you call the side that has the place to write on, or the imprint of the manufacturer's name.

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yea...
Jan 27, 2006 2:48AM PST

The cd (different from dvds) is a piece of plastic, with a metallic sheet stuck on. The metallic sheet is the sheet that you can label, and although your drive reads through the plastic part, the actual data is on the other side of the plastic, on that metallic sheet. got it?

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Bottom Line: Don't Bake Your CD/DVD-RW's
Jan 27, 2006 12:12AM PST

The "stress test" to show degradation used temperatures of 90-100 degrees CELCIUS. That's over 200 degrees FAHRENHEIT.

So the bottom line is:

DON'T USE YOUR OVEN TO STORE YOUR CD-RW or DVD-RW COLLECTION. For you kiddies, this also means don't store your CD-RW's loaded with stolen music on your car's dashboard in the hot summer sun.

If you keep your CD-RW or DVD-RW indoors on a shelf or out of the sun, you can be fairly satisfied that it will still be usable in 100 years. And by that time you'll have probably upgraded to the new 1/2" optical chip storage, the next generation of Flash ROMs.

So this "concern" is a snoozer.

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DVD +RW use
Jan 27, 2006 12:39AM PST

I agree on not paying the price for DVD RW media, except... Happy

I use DVD+RW to record TV movies on an RCA 8000N DVD recorder, for later viewing. I edit the movie and ''hide'' all of the commercials, then re-record it to DVD+R. I erase the RW and use it many many times. The end result is a collection commercial-free movies on +R media that will probably outlive me. Happy

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I use cd-rw, but not for archiving
Jan 27, 2006 12:55AM PST

I like this post a lot. The one thing I would add is that cd-rw media does have its place. I don't use them for archiving, but I have a couple of discs that I use to transfer files between my desktop and notebook. One could easily use a thumbdrive or other removable media, but cd-rws are very cheap in comparison, and pretty well any computer built these days can burn them, so they make a pretty good option.

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What about the "Inkjet" printable lables & "lightscribe" ?
Jan 27, 2006 1:06AM PST

Can anyone shed any light (no pun intended) on the newer, or more recently available, inkjet printable lables? Are their adheasives more stable, or is there a problem about them too? I thought they weould be somewhat of an advantage even if I didn't print on them because the printable surface would "provide" some "protedtion" to the "foil" or whatever it is on the back of CD's that when it get's scratched looses all of the data in that area.

A further extrapolation or carry on/over is a similar question about the newest "technology" the HP "Lightscribe" CD's and DVD's don't they by definition have the dies, or whatever on both surfaces, and would that have any affect or effect on the longevity of them?

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RW-media
Jan 27, 2006 1:12AM PST

The basic idea about RW-media is that you rewrite. RW-media are great for transfering data between different computers or making temorary back-ups.

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RW Media
Jan 27, 2006 1:13AM PST

I agree that you should NEVER save any important data on RW media. But there is a place for this media. I use RW for temporary backups (generally useful for only a few months anyway). If you back up every month, and keep three sets in the rotation, the data only has to survive for 3 months. I've never had such a backup fail if I needed it.

I also use RW media to offload DVD files from my digital video recorder. Then I either transfer the contants to read-only disks if I want to keep it, or I recycle the RW disk for another use. Again, short time needs.

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why?
Jan 27, 2006 1:28AM PST

Why did Barry say about labelling ... on the side of the data???? No way!!!
You should NEVER EVER write or label the data side of any R or RW disc!

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Labeling the Data Side of a CD-R,
Jan 27, 2006 2:53AM PST

You may have misunderstood the comment. The data side of the CD-R is not the clear side which is read by the laser beam. The data layer is actually on the other side, protected by only a thin overlayer of spun on laquer (with or without an overprinted label). You must label this data side because writing on or otherwise labeling the other side would block the laser beam and make the disk unreadable.

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how long do burned CDR's and CD-RW's last
Jan 27, 2006 1:50AM PST

I'm as big a fan of technology as the next guy. We have both MAC as well as PC technology. Love the improvements in the digital photography area. However, the bottom line is, if you want to have a picture to last ... it needs to be on a negative. That, when stored adequately (archival sleeve etc) will take the test of time.

Here at Diagraphix, we not only still pull picture files for our customers which are well over 10 years old, but we finish pictures for museums on very old negatives. Any picture taken which needs to be preserved (oil & gas, mining, exploration, reclamation etc) is always taken with analog technology.

This is not only the best (responsible) option for businesses, it also sometimes is a smart personal choice. Such events as weddings, births, reunions ... think about it ... how long do you want these to last ?

Although the digital camera technology has come a long way (we do use it also), any picture which is deemed vital either personally or to a business, should be taken on a negative. Then ... you know for sure for how long this will picture be available to you.

Just my 2 cents worth ...
Have a great day all ...
Diane
www.diagraphix.com

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factory pressed CDs and DVDs
Jan 27, 2006 3:08AM PST

I think this is the best way to go on music if you are a collector since the quality control can but not always be better.
I've noticed more variation in quality with home made or(burned in copies. The time it takes to copy or minimize the possible defects in copying a song can be excruciating.

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Compliment
Jan 27, 2006 3:09AM PST

Barry W. This is the most comprehensive and well described explantaion of a particular topic I have ever seen. You must be in the business. I applaud you. The information has helped me tremendously, THANKS.

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Reply How long do burned CD-Rs and CD-RWs last?
Jan 27, 2006 3:27AM PST

Iv found if that CD's are proberly the most unreliable source of storage i prefer the LP and have a great device that lets me put tracks from my computer on my LP's. I also have a huge CD collection though and after losing all my computer tracks i reliased i needed more than my computer to back up my CD. I have taken advantgae of being able to have an additional hard drive. I brought a harddrive for

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Bravo for a first rate summary of the situation
Jan 27, 2006 3:33AM PST

I truly believe that your review of the issues involved with CD & DVD longevity is one of the clearest & most concise writings I've seen on most any technical subject. Thanks so much.

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Wrong on Factory-pressed
Jan 27, 2006 3:41AM PST

This may have been covered elsewhere in the sea of replies, but the statement "In a pressed CD, the data is literally "molded into" (actually pressed into) the media and will not disappear unless the CD is physically damaged" is misleading. Rot of the metallic layer is common, especially in discs produced early in the history of commercial CDs but also seen periodically in much newer discs. The discs (or at least parts of them) become unusable to play (or to rip to a CD-R.)

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Am I impressed or what?
Jan 27, 2006 4:34AM PST

Thank you Lee Koo for all that great concise and understandable information. This one article is invaluable especially since I have been archiving data on CD-RW which I now know to be a big no-no amongst other things.

I sure would like to have your email or other kind of contact information as computer knowledgeable people like you are a golden find. In the words from Wayne's World, I bow before you and state "I am not worthy". Wink

Again thanks and I will share this with several of my Assoicates.

Irish Bob

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Don't thank me--thank the CNET community members who
Jan 30, 2006 8:11AM PST

participate in the newsletter and these here forums! I'm only on the side lines directing the Q&A --the rest is all up to our members. Job well done everyone!

-Lee

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cd-rw and dvd-rw
Jan 27, 2006 4:48AM PST

Don't go too far, Barry - I find RW media invaluable for checking the end product and avoiding the coaster pile. Burn it, save the project, check the disc on the player (obviously, I am talking mostly about aspect ratio and audio playability on dvd's), then burn it again on CD-R or DVD-R. I'm probably up a couple of dozen discs with this technique.

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My experience with CD-R
Jan 27, 2006 4:56AM PST

I just copied a bunch of CD-Rs I have recorded over the years to my hard drive to prepare for writing to DVD-Rs. The oldest CD-R was about 7 years old and it even had a full adhesive label on it (I don't do this anymore since I read about the possible problems). The CD-R was essentially full of data and I received no errors in reading it.

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Another note on longevity
Jan 27, 2006 5:04AM PST

Though there are many different answers as to how long any optical media may last, it is a moot point. 10-15 years is most likely long enough since the technology continues to change. Once a new technology "takes over" in the market place you have to convert all your old media over to the new anyway. This has been a big problem with any person/company/organization/etc. that has large amounts of data to archive.

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(NT) (NT) How long do the Gold plated CD/DVD's -+R/RW last?
Jan 27, 2006 5:55AM PST

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