What is the difference between factory-press CD, CD-R and CD-RW ?
On a factory-press CD, data is stored in transition between pits and lands (low and high reflectance) so that Laserdiode of the CD-ROM drive can pick up and recognize the signal. On a CD-R, on the other hand, a pregrooved (physical tracks) Photosensitive Organic Dye is used to record digital information. Laser beam with high energy can change the reflectance of the photosensitive dye so that holes and lands (higher and lower reflectance) can be made hence picked up by CD-ROM drive’s laserdiode.(see figure below) However since CD-RW discs have a reflectance of only around 15~25%, which is about a third to that of pressed CD or CD-R, they must use a laserdiode that is more optically sensitive. Therefore the CD-RW discs cannot be read by ordinary CD-ROM laserdiode, but those with a wider range of reflection acceptance .This kind of CD-ROM drive is Multi-Read capable. Nowadays newer CD-ROM drives come with this feature. Philips, the originator of the compact disc storage solution, has more
