For nearly two decades, CDs have been a medium of choice for archiving computer data, and they were later joined by DVDs. Anyone who has suffered from data loss knows how important it is to back up computer files – especially photograph collections. As a photo storage option, burning photo files onto a CD or DVD is fast, simple, and secure. Pictures stored on disc aren’t prone to loss if your computer crashes, and they can’t be accessed by hacking your computer or online accounts. But CD archiving and DVD archiving have their own potential issues, which need to be addressed in order to maintain a safe archival collection of your photo files for many years.
Potential CD Archival Problems
Although CDs and DVDs are very familiar and seem to be quite durable, the discs are actually fairly delicate things. The layer of a disc that holds the data is a thin layer of either aluminum or gold under a layer of protective lacquer. The protective layer is necessary for several reasons, but one of them is potential oxidation from air touching the data recording layer. If the aluminum in a disc oxidizes, the data stored at that location is lost.
Other issues can also plague CDs and DVDs. Physical damage can erase data on either side. The top side of a CD is actually more sensitive to damage than the “shiny” side on which the data is written, therefore damage on either side of a CD can ruin your data. Other environmental factors can also affect the materials in a CD or DVD, including the jewel cases in which the discs are most often stored. Plastic jewel cases may "outgas" harmful material, which can damage a disc.
Any of these types of damage can lead to "CD rot," a condition where CDs become unreadable. No CD has an indefinite shelf life. The "normal" lifespan of a CD or DVD is considered to be between two and 20 years. Protecting discs properly can extend their life and preserve the data written on them, which is especially important if the data is irreplaceable, such as a family's entire collection of special photographic memories.
Protecting CDs and DVDs
To protect and extend the life of an archival CD or archival DVD, proper storage and handling is key. Jewel cases should be replaced with binders containing disc storage pouches, which both saves storage space and prevents damage from outgassing.
Archival discs can be protected by storing them with anti-corrosive inserts. These inserts prevent oxidation by keeping air away from discs to prevent oxidation of the metal layer. You can invest in archival quality storage pouches, which include these protective inserts, or you can get adhesive anti-corrosive inserts to attach to jewel cases. Archival quality inserts can extend the life of a CD or DVD many years past its normal lifespan.
Correct handling of CDs and DVDs is also important to prevent corrosion and other damage. Discs should only be handled by the outer edges or the center hole. Avoid touching either surface of the disc and keep both sides of the disc clean. This protects the disc – and your computer equipment – from getting accidental dust or dirt inside. Only open cases or pull discs from pouches when you want to use the discs and return discs to their protective cases as soon as you’re finished with them. Keep CDs and DVDs out of UV light to prevent damage and store them upright rather than horizontally. Gold discs are also less prone to oxidative damage than silver aluminum ones.