CD Terminology Below, you'll find the most common terminology that relates to CD duplication. Even if you are new to duplication, the terms below may help you learn more. BLER Block Error Rate. This is the raw digital error rate before any type of error correction. CD This the Compact Disc, a digital medium that's formed of a 12cm polycarbonate substrate, a reflective metalized layer, and a protective lacquer coating. CD-R Compact Disc-Recordable. The term CD-R is used to describe the technology of recordable CD along with the equipment, software, and media that are used to make the recordable disks. Data layer With CD-R media, this is the organic dye that is sandwiched between the polycarbonate substrate and the metalized reflective layer of the media. CD-R disks don't have any data on them at all until the are recorded. Injection Molding This is a manufacturing method where the molten material is forced into a mold, normally under high pressure, then cooled so that the material will take on the shape of a mirror image in the mold. Media or blanks CD-R media are the disks that are used to record digital information using a special recorder and premastering software with a computer. These discs are made of a polycarbonate substrate, a layer of organic dye, a metalized reflective layer, and a coating of lacquer for protection. Organic dye The data layer of CD-R media is made from a dye that is melted during the process of recording. Where the dye is melted, becomes opaque or refractive, scattering the reading laser so that it isn't reflected back into the reading sensors. Reflective layer This is the metal later that sits on top of the dye that reflects the laser beam back to the reading assembly. This is normally 24k gold in CD-R disks, although it can be silver as well. (word count 307) PPPPP