Disc rot affects CDs, DVDs or LaserDiscs in different ways depending on how they’re manufactured and structured. Generally speaking, disc rot occurs due to chemical reactions with the reflective layer of the disc, ultraviolet light damage, scratches that expose the delicate and corrosive layer to environmental factors, or the deterioration of manufacturing materials.
CDs are often touted as the most durable physical music format because of the lack of contact during playback, compared to vinyl records and cassette tapes. Hell, I’ll admit, that with the exception of surface abrasions, I thought there was little you could do to corrupt a compact disc. Check out the BBC’s Tomorrow World’s totally convincing demonstration of the marvels of the new CD format:
Which is why I was caught off guard when I came across this article on disc rot on Motherboard. Great, as if it wasn’t enough that my stylus is wearing out my records, and my tapes are all unspooled – now I have to worry about the degradation of my CDs, DVDs and LaserDiscs as well. In fact, no one knows how long CDs can last. The answer is dependent on a number of factors, including where the disc was manufactured and how it is stored.
So why have we been treating these flat plastic donuts as an indestructible format for music and video when really they’re a delicate, carefully balanced alchemy of audiovisual data?
CD Disc Rot
In the case of CDs, disc rot is the effect of oxidation of the reflective layer of the disc, resulting in what can look like bronze discoloration, or as one victim described it, “a constellation of pinpricks” in the data layer of the disc. As anyone who’s suffered the misfortune of a scratched or scuffed disc CD will know, it doesn’t take a hell of a lot of damage to render the disc unreadable, and once that data is gone, it’s gone for good. CD degradation can be caused by mishandling or improper storage, but disc rot is typically caused by a chemical reaction with the reflective layer of the disc.
DVD Disc Rot
Though they look almost identical to CDs, DVD structure is a little different, using a plastic disc over the reflective layer. This is good news if you get a scratch on your disc as it means it’s less likely to reach the reflective layer and expose it to environmental damage. However, because of this structure, they can also suffer from delamination, where layers of the disc separate. On the disc, delamination can look like a coffee stain. Poor case design has been blamed by some as the case for DVD disc rot. During playback, DVD disc rot appears as the picture pixelating or freezing in a specific spot, skipping, or again, becoming unplayable.
Is Blu-ray Safe from Disc Rot?
It seems less prevalent than for CD, DVD and LaserDisc, but it would be unwise to rule out Blu-ray disc rot. There are a few reports of disc rot on Blu-ray which has been described as ‘small mould blooms’ below the surface, rendering the disc unplayable.
The name given to LaserDisc’s own special brand of disc rot suggests the laser is to blame – similar to stylus wear – but again, it’s just the degradation to the disc. Speckling in the video and crackling in the audio worsen as disc rot advances. It’s usually attributed to oxidation of the aluminum layers by poor quality adhesives used to bond the disc halves together. Single-sided discs rarely suffer as badly as double-sided discs do.
LaserDiscs from specific manufacturers seem more likely to fall prey to laser rot. MCA DiscoVision discs are notorious for it, as well as discs pressed at Sony DADC in Terra Haute. Conversely, manufacturers like Kuraray were well known for their meticulous practices and have seen few instances of laser rot, to date.
Can I Prevent Disc Rot?
Unfortunately there doesn’t seem to be a surefire way to prevent disc rot due to many instances appearing due to manufacturing faults. However, proper care will help from exacerbating the problem, and it’s a timely reminder that your discs are by no means indestructible.
While some of the following tips are eye-wateringly obvious, they’re also often ignored. So let’s take it from the top.
Tips For The Correct Treatment Of Your Discs:
- Handle your discs correctly, touching only the outer edges and hole in the center. While it’s probably second nature by now to be cautious with the reflective underside of discs, you should also be careful of the top, printed layer as damage to this side can also impact playback.
- Store your discs in an upright position. Avoid keeping them in stacks, much like you would vinyl records. They should also be kept in a cool, dry environment.
- Keep your discs in jewel- or keep cases rather than paper sleeves. Anchor the disc using the anchor pin in the center of the case. This is the best way to ensure you’re preventing scratches and damage inside the case. If the anchor pin is broken, it’s best to replace the case. Stick to one disc per case, and always return the disc to the case after play (e.g. don’t leave it on top of the stereo)
- Label discs with a water-based marker. Hard tipped pens and chemicals can be abrasive and do damage to the data on the disc.
- Check the quality of the disc before you buy – especially for secondhand discs. Look out for scratches, discoloration or what looks like pinpricks in the disc. If you’re buying recordables, spring for the higher quality version.
Discs made with gold as the reflective layer are less vulnerable to disc rot, as it’s a less corrosive material, though obviously, these are rarer than their (much cheaper) aluminum counterparts. And sadly, your CD-Rs and DVD-Rs are more likely to suffer from disc rot due to the type of organic dye used in recordables.
So the takeaway here is treat your discs well and they could last you a lifetime. Or they might not. I don’t know anymore, this disc rot thing has thrown my whole world into chaos.