While most people are aware of the processes involved to duplicate a CD, DVD or Blu-ray disc, the term Replication is not as well understood. Replication produces a similar result and is a very economic method of producing thousands of Blu-ray, DVD or CD discs. You can check this link www.ommdvd.com/ to know more about DVD replication process.
The process of DVD replication (or pressing), involves firstly making a glass master and then pressing copy discs from this master. Traditionally offset or silkscreen printing is used to print directly on the face of the disc although high speed UV cured Digital disc printing is emerging in the market.
Replication takes a bit longer than DVD, CD and Blu-ray duplication, due to the time it takes to create the glass master, metal stamper and to set-up the offset or silkscreen CD and DVD printing machines. This production method tends to be the most cost effective for bigger runs of several thousand plus units.
During the traditional mastering process, a polycarbonate blank optical disc is stamped with millions of tiny indentations called pits, which are moulded in a spiral from the centre of the disk outwards. The disc is then coated with a thin layer of aluminum, giving the disc its characteristic silver colour. Unraveled and laid in a straight line the spiral of data would stretch for several kilometers.
Pits and Lands representing the data are created on the disc surface in several ways depending on how the disc is manufactured. The two types of optical discs created are replicated discs and recordable discs (CD-R and DVD-R). The method that they are read is similar.
A laser light is directed at the disc. When the light hits a land it is directed straight back towards a sensor. When the light hits a pit it is scattered, thereby reducing the intensity of the light reaching the sensor. The signal received back is either a 0 or a 1.