Many people find it convenient to use a marker on a CD or DVD for home-recorded media, but controversy persists over the practice. At issue is the thin layer that protects the writeable surface that lies just below the label. In some cases ink might degrade protective coatings over the long haul, resulting in a disc that will eventually generate errors. However, it would appear from general chatter in the Internet community that the majority of people that use markers on media haven’t experienced problems.
A study performed by Media Sciences subjected marked CDs from different manufacturers to 100 hours of high humidity (85% relative), and temperatures of 140 degrees Fahrenheit (60 degrees Celsius) to simulate accelerated aging. Results indicated no single disc type or ink marker performed consistently better than another. All discs degraded, with the upshot being that using a marker on a CD potentially reduces the life of the media to an estimated 20 years. However, Media Sciences itself points out that there are too many variables to offer a definitive answer.
Ink formulas are one factor when it comes to using a marker on a CD. Manufacturers are constantly changing their processes and materials. Chemical interactions between ink formulas and materials used in media manufacturing are unpredictable as such. Media Sciences did deem water-based inks safest, though some media packaging recommends alcohol-based markers for their discs. In all cases use a soft, felt-tipped marker. Ballpoint pens should not be used as the sharp tip can damage the disc. Solvent-based inks such as those used in permanent markers might also be more harmful to some types of discs than other ink formulas.
“Printable discs” have an ink absorption layer for ink-jet printing, (an available feature on some ink-jet printers). The ink absorption layer is a paper label designed to protect the writeable surface and its coating beneath, adding one more safeguard for those who prefer to use a marker on a CD or DVD. Storage and handling of media also affects its life. Small scratches, fingerprints and dust can make a disc unreadable. Environmental factors, such as keeping CDs in a car, subjecting them to heat spikes and humidity can also cause damage.
If you take good care of your discs and find a 20-year life expectancy acceptable for the media, choose a marker made for writing on CDs and DVDs to reduce risk as much as possible. Sanford has a special line of Sharpie® markers for CDs and DVDs. Other companies also make CD/DVD markers. Dixon’s RediSharp Plus!®, Staedtler’s Lumocolor CD/DVD Markers® and Memorex’s CD Markers® are a few examples.
To be safer still, you can write with a marker on a CD or DVD on the clear inner hub of the disc. This doesn’t afford much room, so some people use an indexing system, placing a code in this area. Discs fill from the inner hub out towards the edge. Once written to, the disc becomes darker. If the disc isn’t full, try using a marker on a CD or DVD along the outer edge so the ink isn’t positioned over data on the opposite side.
If you prefer labels, use those made for CDs and DVDs. Adhesives and glues on other types of labels might damage your media. Additionally, a small label not designed to fit over the entire disc can unbalance it as it spins, creating wobble.
While countless discs have survived many years after being labeled with a marker, you might want to take special precautions with home movies or other materials that are irreplaceable. One option is to keep such materials backed up to an external hard drive with a USB port, which can easily be moved from laptop to desktop, or from family member to family member. If the CDs or DVDs should ever fail, the original files will still be available for transferring to new media.