Exploring

Inherent Vice: Optical Media

Other Coatings

Because the data layer is so close to the label side of the disc in a CD, a thin layer of lacquer is usually applied to protect the data layer from exposure to the environment. (This is not needed in a DVD, due to the presence of a polycarbonate layer on both sides of the disc.) This lacquer layer may protect the CD somewhat from damage due to writing or labeling, but care must still be taken not to damage the coating during handling. Sometimes an extra surface layer is added to a CD or DVD to provide a surface for labeling, but this also must be treated carefully. The only truly safe surface for labeling is the clear inner hub or the "mirror" band, which do not contain data.