DVD-R discs are
recordable DVD media that can be written to only
once. The discs can be writen in standard DVD writer
drives. The DVD-R format was developed by Pioneer
in 1997 and is the most commonly used type of writable
DVD (other types include DVD+R and the re-writable
DVD-RW/DVD+RW).
DVD-R discs have
much higher storage capacities than CD-R discs by
using smaller pit sizes and narrower track pitches
in the spiral groove that runs around the
discs. These smaller pits and grooves require a different
wavelength of laser light (650nm) to that used in CD drives (780nm) and therefore DVD discs cannot be read
in standard CD drives.
The DVD-R discs
are available in two main sizes of circular diameter
12cm and 8cm. The 12cm discs are the typical size
for CDs and DVDs and have a capacity of 4.7GB and
the 8cm discs have a capacity of 1.4GB.
DVD-R discs are
made from two 0.6mm polycarbonate layers that are
bonded to each other. One of the layers contains
a grooved reflective surface and a recording dye
(hence the slightly green/blue colouring of DVD-R
discs when compared to replicated
discs). The other layer is just clear and is
used to create the required disc thickness of 1.2mm.
Below is a diagram
illustrating the difference in track pitch between
CDs and DVDs:
View other CD
and DVD production FAQs.
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