or should i be using the more expensive brand of CD wallets? I've been using the cheapie ones... (i like "media source" because it's a looseleaf binder)CDR = time bomb?
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CDR = time bomb?
a few messages on this forum seem to imply that CD-Rs inevitably fail after a certain amount of time... is this true? some of my CDR discs that i copied last year are, maddeningly, giving telltale "scratch" noises in some places... is there a better brand i should be buying? i was kind of hoping i'd be able to play these CDs for my grandkids and stuff... or should i be using the more expensive brand of CD wallets? I've been using the cheapie ones... (i like "media source" because it's a looseleaf binder)
or should i be using the more expensive brand of CD wallets? I've been using the cheapie ones... (i like "media source" because it's a looseleaf binder)
Good question. I did a little surfing just now. Here's an interesting quote from a 2001 article from Information Week about the dyes, which are the main reason for failure over time:
http://www.informationweek.com/story/IWK20010719S0003
Cyanine is the most widely used and cheapest CD-R dye. It looks bluish (as its name suggests) or blue-green when backed by a silver foil, but can look distinctly green when backed by gold foil.
Estimates of the dye's useful life range from 10 years to as high as 75 years. But data-storage is an inherently conservative business, so it's wise to assume the worst and plan only on a lifespan of 10 years or so. This makes cyanine-based CD-Rs OK for most routine backups and legal archival purposes. But they may be less acceptable for very long-term historical, business, or family archives, unless you plan to re-record the data onto a new or different medium every decade or so.
Phthalocyanine is an-almost transparent, very light aqua color, and usually is backed with gold foil, so a phthalocyanine-based CD-R usually looks golden. For this reason, and because the dye is exceptionally durable, it's sometimes called the "gold standard" of CD-Rs.
Although phthalocyanine CD-Rs may be expensive overkill for routine storage, they're tops for long-term archiving, with a reputed shelf life of something like 100 years.
Formazan is a light green color, and is usually backed by gold foil, producing a greenish gold CD-R. It's actually a hybrid of cyanine and phthalocyanine, and combines the qualities of both.
Metallized AZO is a dark blue, and is normally used with silver foil, which gives the CD-Rs a dark blue appearance. Metallized AZO is said to have a long shelf life, approaching that of phthalocyanine.
http://www.informationweek.com/story/IWK20010719S0003
Cyanine is the most widely used and cheapest CD-R dye. It looks bluish (as its name suggests) or blue-green when backed by a silver foil, but can look distinctly green when backed by gold foil.
Estimates of the dye's useful life range from 10 years to as high as 75 years. But data-storage is an inherently conservative business, so it's wise to assume the worst and plan only on a lifespan of 10 years or so. This makes cyanine-based CD-Rs OK for most routine backups and legal archival purposes. But they may be less acceptable for very long-term historical, business, or family archives, unless you plan to re-record the data onto a new or different medium every decade or so.
Phthalocyanine is an-almost transparent, very light aqua color, and usually is backed with gold foil, so a phthalocyanine-based CD-R usually looks golden. For this reason, and because the dye is exceptionally durable, it's sometimes called the "gold standard" of CD-Rs.
Although phthalocyanine CD-Rs may be expensive overkill for routine storage, they're tops for long-term archiving, with a reputed shelf life of something like 100 years.
Formazan is a light green color, and is usually backed by gold foil, producing a greenish gold CD-R. It's actually a hybrid of cyanine and phthalocyanine, and combines the qualities of both.
Metallized AZO is a dark blue, and is normally used with silver foil, which gives the CD-Rs a dark blue appearance. Metallized AZO is said to have a long shelf life, approaching that of phthalocyanine.
and here's everything you needed to know on media, from the CR-R FAQ. (forgot about that):
http://www.cdrfaq.org/faq07.html#S7-5
One quote:
The manufacturers claim 75 years (cyanine dye, used in "green" discs), 100 years (phthalocyanine dye, used in "gold" discs), or even 200 years ("advanced" phthalocyanine dye, used in "platinum" discs) once the disc has been written. The shelf life of an unrecorded disc has been estimated at between 5 and 10 years. There is no standard agreed-upon way to test discs for lifetime viability. Accelerated aging tests have been done, but they may not provide a meaningful analogue to real-world aging.
Exposing the disc to excessive heat, humidity, or to direct sunlight will greatly reduce the lifetime. In general, CD-Rs are far less tolerant of environmental conditions than pressed CDs, and should be treated with greater care. The easiest way to make a CD-R unusable is to scratch the top surface. Find a CD-R you don't want anymore, and try to scratch the top (label side) with your fingernail, a ballpoint pen, a paper clip, and anything else you have handy. The results may surprise you.
Keep them in a cool, dark, dry place, and they will probably live longer than you do (emphasis on "probably"). Some newsgroup reports have complained of discs becoming unreadable in as little as three years, but without knowing how the discs were handled and stored such anecdotes are useless. Try to keep a little perspective on the situation: a disc that degrades very little over 100 years is useless if it can't be read in your CD-ROM drive today.
http://www.cdrfaq.org/faq07.html#S7-5
One quote:
The manufacturers claim 75 years (cyanine dye, used in "green" discs), 100 years (phthalocyanine dye, used in "gold" discs), or even 200 years ("advanced" phthalocyanine dye, used in "platinum" discs) once the disc has been written. The shelf life of an unrecorded disc has been estimated at between 5 and 10 years. There is no standard agreed-upon way to test discs for lifetime viability. Accelerated aging tests have been done, but they may not provide a meaningful analogue to real-world aging.
Exposing the disc to excessive heat, humidity, or to direct sunlight will greatly reduce the lifetime. In general, CD-Rs are far less tolerant of environmental conditions than pressed CDs, and should be treated with greater care. The easiest way to make a CD-R unusable is to scratch the top surface. Find a CD-R you don't want anymore, and try to scratch the top (label side) with your fingernail, a ballpoint pen, a paper clip, and anything else you have handy. The results may surprise you.
Keep them in a cool, dark, dry place, and they will probably live longer than you do (emphasis on "probably"). Some newsgroup reports have complained of discs becoming unreadable in as little as three years, but without knowing how the discs were handled and stored such anecdotes are useless. Try to keep a little perspective on the situation: a disc that degrades very little over 100 years is useless if it can't be read in your CD-ROM drive today.
Ron's posts are excellent. The gist: blue and green discs are bad, gold and silver discs last longer. The dye can simply lose the impressions burned onto it after time.
There are two other factors besides the dye used based on the adhesion of the dye layer to the disc: scratches and bubbles.
Keep in mind that the data on a CD and CD-R is kept on a thin sheet adhered to the top of the disc, not on the surface of the underside of a disc. The laser must penetrate through the silicone/plastic disc to read the data. You can peel the data layer of a CD-R off the top of the disc, unlike a commercial CD. (As an experiment, apply a petroleum thinner or spot remover (Goof Off) to the top of the disc, and you can sometime remove the entire data side.)
Scratches to the underside are correctable. The underside can be resurfaced to eliminate scratches that impair the ability of the laser to get to the data. Scratches to the top side ruin the CD.
First, the data layer of a CD-R is more flimsy and scratches much easier than the data layer of a commercial CD. Some brands of CD-Rs contain protective layers that help prevent scratches. But you should always be gentle with them and not treat ANY CD-Rs like you would a CD.
Second, the "glue" can fail over time and create "bubbles" in the data layer. Extreme heat or cold, and solvents can accellerate the failure of the "glue."
There are two other factors besides the dye used based on the adhesion of the dye layer to the disc: scratches and bubbles.
Keep in mind that the data on a CD and CD-R is kept on a thin sheet adhered to the top of the disc, not on the surface of the underside of a disc. The laser must penetrate through the silicone/plastic disc to read the data. You can peel the data layer of a CD-R off the top of the disc, unlike a commercial CD. (As an experiment, apply a petroleum thinner or spot remover (Goof Off) to the top of the disc, and you can sometime remove the entire data side.)
Scratches to the underside are correctable. The underside can be resurfaced to eliminate scratches that impair the ability of the laser to get to the data. Scratches to the top side ruin the CD.
First, the data layer of a CD-R is more flimsy and scratches much easier than the data layer of a commercial CD. Some brands of CD-Rs contain protective layers that help prevent scratches. But you should always be gentle with them and not treat ANY CD-Rs like you would a CD.
Second, the "glue" can fail over time and create "bubbles" in the data layer. Extreme heat or cold, and solvents can accellerate the failure of the "glue."
Just a couple of weeks ago I pulled a CD-R I haven't touched in years out of its plastic sleeve--- and part of the top layer just peeled right off! This was an earlier CD-R with no protective coating on top. I wouldn't expect this to happen with anything made in the last few years. Surprisingly, the last 2/3 of the disc still plays fine!
I have had Kodak Gold disks--using the best dye and with one of the best protective coatings on the market--fail after only two years when stored under ideal temperature conditions and literally not being touched. (I took it out of the jewel case I had not opened in two years, and it skipped all throughout the disk because the dye failed. It was not scratched or bubbled). I also have had cheap CD-Rs survive in my book for four years despite rough handling.Mike wrote:Just a couple of weeks ago I pulled a CD-R I haven't touched in years out of its plastic sleeve--- and part of the top layer just peeled right off! This was an earlier CD-R with no protective coating on top. I wouldn't expect this to happen with anything made in the last few years. Surprisingly, the last 2/3 of the disc still plays fine!
A friend of mine recorded several hundred compilations on cheap-o, generic, blue CD-Rs without knowing the difference, and literally half his compilations became skittish after a year and a half.
That only emphasizes the inconsistent nature of CD-Rs: they might work fine, but their long-term viability is so inconsistent that they are not long-term guarantees. But they still are fantastic short-term resources that I find irreplaceable for creating more-efficient compilations (more songs per CD) of the original CDs that I now keep at home for safekeeping.
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Mr Awesomer
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In addition to media issues, the hardware used to burn said disc can effect the quality and longevity of the discs produced.
Reuben Brown
Southern California
Southern California
Exactly. Not all data errors come out as skips or jitters: either because the human ear doesn't notice it or because the player can figure out the music without all the relevant data. (I can't remember which one.) Skips or jitters only comes out when the error or gap in data is significant or large enough; minor data flaws do not always show up. When you burn quicker or on cheaper disks or with sub-par software/hardware, you increase the risk of missing some data, which increases the risk that a corruption of an already-weak data spot could result in an audible skip or jitter.
Technically, a perfect source disc, a perfectly clean lens, a perfect destination disc, and the right software and hardware should produce just as good a copy at 1x as it does at 48x. The speed shouldn't affect it unless 1) the hardware/software really can't handle the speed, 2) the source disc is dirty/scratched so as to interfere with reading the data, or 3) the disc or lens is dirty/scratched so as to interfere with the laser doing its job. Slowing it down decreases the impact of these factors and gives the computer time to compensate.
Technically, a perfect source disc, a perfectly clean lens, a perfect destination disc, and the right software and hardware should produce just as good a copy at 1x as it does at 48x. The speed shouldn't affect it unless 1) the hardware/software really can't handle the speed, 2) the source disc is dirty/scratched so as to interfere with reading the data, or 3) the disc or lens is dirty/scratched so as to interfere with the laser doing its job. Slowing it down decreases the impact of these factors and gives the computer time to compensate.
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Toon Town Dave
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What kind of plastic was the sleeve made of?Mike wrote:Just a couple of weeks ago I pulled a CD-R I haven't touched in years out of its plastic sleeve--- and part of the top layer just peeled right off! This was an earlier CD-R with no protective coating on top.
I can't emphasize enough DON'T USE VINYL/PVC sleeves for important stuff. PVC oil leeches out of this material over time and destroys stuff it contacts. I've seen yellowed baseball cards and silver coins covered in green slime that were stored in PVC sleeves. I expect bad things would happen to CD's too.
Use polyethylene/polypropylene (cheap and okay) or mylar (expensive and best) for archival storage. If/when the sleeves start to feel oily, replace them quickly.
I use 100% polypropylene sleeves from Univenture. I'm wondering if the sharpie marker weakened the disc, or if it was just a crappy brand. I'll post when I get home and check it out.
i was buying for a while the blank cds that look just like regular cds -- i like how they look, more professional, just a clear shiny top. but maybe the ones with the frosty top (that spell out the brand name, etc.) are better because the top is protected more?
and how does one know what his sleeves are made out of?
and how does one know what his sleeves are made out of?
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funkyfreak
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