CD and DVD Duplication Optical Disc Types

Although all CDs and DVDs may look the same, and they do comply to standard sizes, there are different types of discs used for CDs and DVDs and the different functions and format types. Therefore, in order to be able to Duplicate the different types of formats the right type of disc needs to be used.

The standard CD was developed out of the same basic theory as the old vinyl records, but using light reflection variations to determine the information. The initial discs were meant solely for audio playback, and designed with a single, read only function as this was all that was required for music albums. However, as the potential applications of CDs developed, so the discs themselves had to also. Though there are now many variations, there are two basic types; recordable and re-recordable. Discs that can only be written to once use an organic dye that is altered to create the variations in reflections required, as this dye cannot be remoulded. Re-writable CDs don’t have this layer of dye. Instead they have crystals that can be heated to change their shape, which in turn varies their reflective properties. As these crystals can be remoulded, the disc can be written to many times. In order to use either of these types of disc in CD Duplication different equipment and software is required, although many CD Duplicating machines now incorporate both as standard

DVDs are read using a laser with a lower wavelength than ordinary CDs, of 650nm compared to the 780nm. As a result, the pits that are created onto the discs that vary the reflection of light can be much smaller, allowing for more of them to be created on the disc and thus increasing the storage size. This can be up to seven times that of an ordinary CD, depending on the type of DVD used. A DVD can either be a single sided disc or a double sided disc and have one or two layers available on each side, allowing for four types of discs using combinations of each and offering varying storage capacities. As with CDs, DVDs can be used for Duplication as DVD-ROMs, writable and re-writable options, each requiring a specific type of disc. There are also DVD video and DVD audio formats that offer very high quality playback for video and audio recordings.

Blue Ray Discs use a laser with a much shorter wavelength still even than DVDs, utilising light in the violet spectrum, allowing for data to be packed much closer together on each layer. This means that up to five times more data can be stored than on a standard DVD. There are mainly two types of discs used for Blu Ray technology, BD-R, which can only be recorded to once, and BD-RE, which can be recorded onto many times. There are three types of BD-R discs and four types of BD-RE discs, each using a different file system and format arrangement that is best suited for different functions. Both BD-R and BD-RE are now also available on Mini Blu-Ray Discs which are much smaller in physical size and used in devices such as camcorders. Other variations of Blu-Ray discs developed include the DB9 and DB5, which are cheaper alternatives, the BDXL which supports much larger amounts of data with 100GB or more, and the IH –BD which is a duel layer disc supporting a read only and a write once layer. Some of these discs are compatible with standard Blu-Ray players but others have their own additional specifications. When duplicating a Blu-Ray disc, the right one for the type of device used to read it, as well as the type of data to go onto it, must be selected.