All optical discs require special care. It is basic, but most users ignore that detail, and as if that weren't enough, they don't need our help to fall apart. The supposed invulnerability of optical discs becomes a simple anecdote against the effects of the so-called disc rot, a combination of physical and chemical deterioration that inevitably leads to read errors, and in the worst case, total data loss.
A disease can present several symptoms at once, and they most likely begin as something harmless. A pain here, a little cough there... honestly, I could write a book about it. But like this humble servant, there are certain everyday objects that suffer health problems. Most of them are avoided with minimal maintenance and caution. Air filter, oil change, voltage stabilizers, cleaning... the list goes on. And then there are others that manifest over time. A good example is the optical discs.
Some people are left heartbroken when they discover that their precious CD collection could end up as dust if manufacturers didn't do their job at the time. The "good" news is that we always have the possibility of making a backup before it's too late. The "bad" news is when there is too much data to back up, or the original disc is irreplaceable.
Disc Rot, the Silent Enemy of Your Optical Discs
Disc rot is not something new. In 1988, a representative of Nimbus Records, the first manufacturer and distributor of CDs in the United Kingdom, dropped the bomb: compact discs would "self-destruct" in eight or ten years. The rest of the companies involved in the CD market wanted to decapitate this representative, but his explanation was precise. The inks used to print on the top face of the discs eat through the protective lacquer that covers the aluminum layer. Once exposed, the aluminum oxidizes, the reading laser does not reflect correctly, and the errors begin.
There are two ways to detect this. The first is to hold the disc up to a light and look on the surface for small pinholes that let light through, no larger than the tip of a needle (basic surface damage can be confused with disc rot in this way). The second is what is described as a "tea stain" on the reading surface. Another variant is the so-called "bronzing" of the disc. Although it is much rarer, an affected disc begins to take on the color of bronze, from the edge toward the center.
And no, disc rot is not limited to audio. PC, Mac, Sega CD, Saturn, Dreamcast... few escape its destruction once it begins. Fans of the LaserDisc format can tell one horror story after another with their "laser rot", also associated with the oxidation of aluminum layers, caused by mediocre adhesives. And vinyl enthusiasts have their hands full. Heat deformation or poor storage, humidity, groove burn, or poor quality vinyl are their enemies.
Now, what can we do? The Library of Congress of the United States shared some data: DVDs are a bit more resistant to disc rot because the reflective layer is inside the polycarbonate, home-recorded discs don't last as long, and proper storage (controlled environment, without large temperature and humidity variations) definitely helps (several decades for a standard disc), as does proper handling.
