The use of DVD and CD archival pens or archival markers is a very cheap way of labeling optical disc media. This method of labeling CDs and DVDs and other optical discs is also considered safe and will not cause damage to optical disc media if certain rules are followed.
The best place to label an optical disc is in the clear hub portion (the portion around the inner hole of the disc) of the disc and this is because there is no information stored in this area of the CD or DVD. Therefore, there is no concern about using the incorrect type of DVD or CD archival pen or archival marker. If a more reactive pen is used, but labeling or writing is restricted to the hub area, then no information will be lost should degradative chemical reactions occur as a result of the pen or marker.
However, the hub area does not provide much space to write. A couple of words can be written, but for the most part, only a code (text, numerical, or alphanumeric) can be written on the disc and the bulk of the labeling information cross-referenced in a database or text file. In some cases the hub area may be obscured by other labeling or manufacturer printing. In these cases, labeling will have to take place in areas of the disc where information is recorded underneath.
When deciding to write on a CD, DVD, or other optical disc in the non-hub area, then it is important to use only a soft felt tipped archival pen or archival marker. Avoid using any writing device that requires pressure to write on the optical disc such as a pencil or regular ink pen. Using minimal pressure to write is especially important with CD media, because the sensitive layers containing the stored information are very close to the top of the compact disc and in fact immediately underneath a thin top protective layer. Applying pressure will cause indents in the metal reflective layer within the disc and likely ruin the disk. For DVDs, the sensitive information layers are in the middle of the disc structure and for Blu-ray discs the information layers are completely at the other end of the disc. As a result, when pressure is applied, it will have less of an effect on these discs and metal layer damage is unlikely. Nevertheless, it is best to use as little pressure as possible when writing on any type of optical media just to be sure.
Next, it is important to choose the correct formulation of archival pens or archival markers for writing on CDs, DVDs, or other optical disc media in the non-hub area of discs. The marker should be a water-based permanent one and not solvent based. Solvent based archival pens or archival markers may damage the protective coating of CDs and result in damage to the information layers immediately underneath the protective layer. As was previously stated, this is less of an issue with DVDs and Blu-ray discs because the information carrying layers are deeper in the disc structure. However, as a general rule, even for these disc types, a water-based permanent marker is best.
Note that just because a manufacturer states that their archival markers or archival pens are safe for CDs and other disc media does not necessarily mean that this is so. Very little research has been performed to verify the safety of specific brands and types of markers in conjunction with their use on CDs and DVDs. Therefore, despite claims being made by manufacturers, it is best to stick with the basic rules already stated and summarized below.