Audiophiles have seen many changes in preferred formats over the past decades – starting with Thomas Edison’s gramophone. The aluminum cylinders eventually gave way to shellac records. Small, black shellac singles eventually transformed to large, black LPs. LPs eventually progressed to 8-tracks and cassettes. After cassette tapes, we saw the final transformation of physical media as far as music goes – the compact disc.
Today, we realize that compact discs, or CDs, were not the life-altering format that they were hyped up to be. In fact, most music in 2018 is carried in a digital format. Still, when the CD was first introduced to the public, they were considered groundbreaking. They promised “Perfect sound forever.”
But, over the past 40 years, CDs, DVDs, and other optical discs have proven to be fallible.
Disc Rot is Deterioration in the Reflective Layer of a Disc
That’s right, over time optical discs are known to deteriorate – eventually to the point of being unplayable. That for-life DVD and long-lasting CD you were so proud of 20 years may not stick around as long as you’d hoped.
The first step to understanding more about disc rot is understanding some of the basics of how optical discs are made. Optical discs are the CDs and DVDs that you’re familiar with – but, there are also other lesser-known optical discs that experience disc rot as well such as the Laserdiscs of the 1970s and various sizes of discs for game consoles.
These discs are constructed of a polycarbonate plastic with embedded “pits” and “lands” representing the zeroes and ones used to digitally construct an audio waveform. The underside of the disc is coated with a metalized, aluminum layer that oxidizes over time. The oxidization interferes with the reflective qualities of the coating, and once it’s severe enough, begins to audibly affect the disc.
Disc rot has left many collectors and music-enthusiasts disappointed as the format was touted as revolutionary. This caused massive, crazed disc sales in the 80’s and 90’s for both CD and DVD formats.
In a 1988 newspaper, Michael Lee a spokesman for Nimbus records, commented on the inflated longevity claims by CD manufacturers.
“ We have been carrying on accelerated life tests and I’m afraid that a lot of compact discs will prove less durable than has been claimed. [And CDs will begin to] fade out after eight years’ use.”
Does Disc Rot Still Happen to Modern CDs and DVDs?
Disc rot happens in varying degrees to CDs and DVDs based on the process of manufacturing used, the year of manufacturing, and the factory where they were produced. There have been several well-known sources of disc rot, including reports of faulty discs produced by Warner Bros around
One well-recorded source of disc rot is the case of Philips & Du Pont Optical UK Limited, or PDO. PDO was a major manufacturer of CDs in the late 80s and early 90s. It was eventually discovered that PDO used a lacquer in the production of their optical discs that was unable to stand up to the sulfur found in promotional disc-case inserts and labels.
Corrosion of discs manufactured by PDO has been described as “bronzing” and is usually noticeable by small patches of slight discoloration. Though most reported problems with PDO CDs were in the 80s and 90s, some problems may still persist today. Luckily, there is an available list of potentially affected discs so you can easily check your collection. PDO suggests that customers inspect their discs in six-month intervals.
How to Avoid Disc Rot
Disc rot is not exclusively avoidable. In some instances it is inevitable. However, there are steps that can be taken to prolong the use of a disc. Many of these are general care tips for a disc but they are worth reviewing regardless.
- Handle CDs and other discs properly. Grasp only from the outer edges and inner-ring. You may think the label is safe but damage to the top of a disc can actually affect playback as well.
- Store CDs upright and in a cool, dry location.
- Store your CDs in their original jewel case as opposed to paper or another carrying case. If you damage the original jewel case, it’s best to replace it with another jewel case. Don’t go on using a damaged case.
- Don’t leave your CDs or DVDs out. As tempting as it may be to leave them in the player or on top of the stereo, go ahead and put them away.
- Use water-based ink is you must label a disc.
- If you don’t know how to clean CDs, be very careful or take them to a professional. If using a cloth, only use a clean and lint-free cloth.
As we mentioned, it is occasionally inevitable that you will experience disc rot. It is dependent on a myriad of different factors, many of which are out of your control. As a precaution, you may want to rip all discs to a digital library as soon as you purchase them. It’s also a good idea to back up your existing library digitally in case of the unfortunate circumstance that your collection eventually starts to experience disc rot.