Collectors beware – there is a new pandemic in 2021 that can effect your entire CD-based games library! Ok, perhaps this statement has been taken out of proportion across the Internet for sensationalist purposes, but the truth is that there is still something that is called Disc Rot that can massively damage your games. The most concerning thing – there is little you can do to prevent this.
What is a CD?
To understand what disc rot is we first need to understand how discs (CD and DVD) are constructed. Both variants of discs have something called a reflective layer. This is the layer that holds the information, or more accurately it is the layer that reflects the laser back to dictate the information held.
A CD will have a polycarbonate layer at it’s base – this is the layer that usually becomes scratched when a disc is mishandled. The reflective layer is next, followed by a lacquer that prevents oxidisation. Above this goes the artwork for the disk.
Now most people think that keeping the polycarbonate layer protected means that the disc will always stay readable, and while this may be correct for the most case, it is not this area that causes disk rot.
What is disc rot?
Disk rot is a case when a CD or DVD becomes unreadable because of chemical or physical deterioration. This can include oxidisation (the thing the lacquer layer tries to prevent), scuffing, ultra-violet damage, reactions with contaminants and also de-bonding of the adhesive used to create the disk. The issue is not new as it was first discovered in the 1980’s on laser discs.
The rot can be identified by holding a disk up to a light source. If it has rot then there will be light appearing through small pin holes or large chunks of missing data. Other identifying marks are things like disk decoloration – a coffee stain-like mark on the underside of the disc, which is sometimes referred to as CD Bronzing – an issue I have faced by overplaying DVD discs.
The issues this causes are errors on games, usually audible, or unreadable disks. Sometimes a game will load but if the rot has affected or removed part of the programming it can cause sudden crashes and make the game further unplayable.
One of the most well documented occurences of this issue is from the GameCube game Metal Gear Solid: The Twin Snakes. There are statements that say most owners of this game perceive disk rot (which appears as chipping paint from the label) on at least one of the discs for this game. Even copies that have been unplayed have major signs of this issue. The issue causing this variant of disc rot is the glue used to seal the label to the top of the reflective layer, not that the discs are infected with FOXDIE.
How can this be prevented?
This biggest cause for concern is that disc rot cannot always be prevented. The easiest way to keep your games safe is to store them in a dry, cool place, with minimal humidity and if possible away from sunlight. The best way of keeping your games in working order it to make sure the label side of the disc is kept free of scratches. Remember that this is the label that keeps the lacquer protected on the reflective layer – scratching the label can seriously damage the data integrity underneath.
However, disc rot can appear on brand new and sealed games as much as older games. Unfortunately one of the biggest causes for disc rot is actually due to manufacturing faults, where the layers have not been correctly adhered to each other, causing untold amounts of issues with the games. DVD’s are safer as they have a protective layer above the reflective layer, but they are also still susceptible to their own version of this issue.
Other variants of disc rot exists for both laser discs and HD-DVD or Blu Ray’s too. Warner Bros. HD-DVD’s that are produced between 2006 and 2008 all developed disc rot not long after production, again showing that manufacturing issues are mainly to blame.
So there you have it – that collection of 3,000 PlayStation 2 games you have sitting in cold storage somewhere may be facing off a nasty fungal-type infection that is slowly removing all the data you have invested in over the years. The odd’s are that your games are fine, but it is definitely something to check for and something to consider when you decide on how to store large collections.
It may also be a good thing to keep in mind when buying second hand media. Although it is uncommon, it shows that the CD and DVD technologies aren’t as hardy as people believed, with manufacturers not considering the long term. Those old cartridges don’t seem so bad now do they?