Table 4: Types of optical discs [35].

Carrier Period Type of recording Composition

CD 1981–today    Digital Base: polycarbonate
Reflective layer: aluminium, varnish, inks

CD-recordable 1992–today    Digital Base: polycarbonate
Reflective layer: gold, silver, varnish, inks

CD-rewritable 1996–today    Digital Base: polycarbonate
Reflective layer: varnish, inks

SACD 1999–today    Digital Base: polycarbonate
Reflective layer: silver
Coating: lacquer

DVDA 2000–today    Digital Base: polycarbonate
Inner layer: aluminium
Outer semireflective layer: gold
Coating: lacquer