The on disc templates show guides for bleed, the physical edge of the disc, the live print area, safety guides and where the mirror band / metallized disc area begins.
Unlike white paper, a disc has three distinctly different surfaces.
a) The regular surface of the disc is silver (or reflective aluminum, technically). Depending on the
lighting and angle at which you hold the disc, the surface appears to have a tonal value of about 15 percent black.
b) The mirror band. This is a highly reflective ring just outside the center of the disc that
contains information about the disc itself; track information, artist, job number, etc.
c) The stacking ring is a lip in the center of the disc, between the mirror band and the hole.
(While not recommended, you can print on this area but your text may look slightly different due to the various textures)