MODEL RELEASED. Compact disc production. Technic- ian in clean room clothing visually inspects a newly-produced compact disc (CD) as part of quality control. The disc stores data (such as music, text or images) as a series of fine depressions on the disc's plastic surface, representing a digitised signal capable of being read by a laser. To reflect the laser light, the coded layer is coated with a fine film of metal which follows the depressions exactly. This layer is covered by another layer of transparent plastic which prevents dust and scratches from affecting the readout. Audio compact discs have high sound quality.