How long will our discs last?

For years now, end users have relied heavily on optical storage media to store their crucial projects. We were encouraged to put our digital photos on a CD-R, and more recently on a DVD-R (or DVD+R). We all bought those shiny discs by the armload, up to 100 at a time. In the next year or two, we’ll be burning them on one of the newer formats, either Blu-Ray, HD-DVD depending how that impending format war shakes out.

I remember a few years ago hearing that NASA was archiving its data from magnetic tape to optical media. I figured that if it was good enough for the space administration, than it should be more than adequate for my last trip to Disney. I now religiously back up my digital photos on optical media upon returning from a trip, just after I unpack my luggage.

Now we’re seeing reports contesting the life span of the optical disc. Earlier this month, an article on Yahoo came out and stated that:

“Unlike pressed original CDs, burned CDs have a relatively short life span of between two to five years, depending on the quality of the CD," Gerecke says.

This was a cause of concern, as I have lots of pictures on these discs, and no desire to start recopying them at this point. The author brings up that the cheaper discs use inexpensive dyes that allow shifting, which results in an unreadable disc. Then again, in the same article, the author suggests not using unreliable hard drives, and recommends magnetic tape. At least in the home market, very few of us ever used, and even fewer currently use magnetic tape to store anything so this recommendation was a little surprising.

On the other hand, now we have some of the disc vendors, specifically TDK and Memorex, saying that their discs can last for seventy years. At least “down under,” in Australia, TDK backs up their claim with a limited lifetime warranty. While I’m impressed with their lifetime warranty, in 70 years, I won’t really care about exchanging the disc for a new one, but rather showing the graduation photos to the grandkids. Of course, I doubt that the makers of the media would willingly admit that their product stinks.

What can we take away from these two articles both released this month? The logical conclusion is that a disc will last anywhere between two and seventy years, which is little help on whether they can be trusted or not for the long term. However, this is an important issue as many of us have a lot of memories riding on these discs.

I started burning my first discs at the end of 1998. Thankfully, they all still are readable, and none of them have gone bad. On the other hand, all of my rewritable media, first CD-RW’s, and more recently DVD+RW’s have gone bad within a year or two. They are ok for an ongoing project, such as a PowerPoint presentaion, but certainly not for archival storage. For archiving purposes, I only use write once media.

Why have discs lasted so long in my personal experience? These are the reasons I think are behind their longevity.

1- They were name brand discs. My first spindle was of 50 Ricoh’s. Those no name brand discs are simply cheap, but don’t have the same quality. Just like when shopping at the grocery store “no frills” saves money, on some items the quality is just not there. On a pound of sugar it may not matter, but with discs it definitely does.

2- Proper storage goes a long way towards disc longevity. Even the best bottle of wine turns to vinegar if not taken care of properly. Discs should be stored vertically in their boxes to avoid warping. Likewise, they should be kept cool, but not frozen. Also, low humidity is favorable for archiving these materials.

3- Keep the discs out of the light. This is true both before burning as well as after. Sunlight could burn some extra pits and valleys into the disc if sufficiently strong, for a long enough period of time. Likewise, the effect of the UV rays on the dyes can cause some degradation. I’ve seen plenty of people that leave their discs, readable side up, on their dashboard of their car. Between the heat, and the light, they’re just asking for an unreadable disc.

4- Avoid those labels. The stickers that folks put on their discs bond with the surface, and may effect what is underneath. Also, never use a ball point pen which can scratch the upper surface. A Sharpie marker, although not too spiffy looking is safe. The newer LightScribe technology is also safe, although I have no direct experience with it.

5- Always hold the disc by the edges. The sweat from your fingers contains salts, and fats that can degrade the optical surface both short term, from smudges, and long term from chemical degradation. Never touching your discs on the bottom avoids this problem. Many people are more careful with the top than the bottom of the disc, which doesn’t make any sense because the bottom contains the data.

So there you have it. With the tips I’ve outlined, I have no doubts that your discs will last a lot more that two years. I’m not sure if they will make seventy years, but recopying them every few decades onto a newer format may be a good thing. It will give you a legitimate excuse to look at those old photos that otherwise are in a dark shelf in the back of the closet.