CD-R Technology is used for Duplication.
A CD-R in the most simple terms is a recordable compact disc. It was first produced in 1988 and originally called CD-WO or CD Write Once. By 2003, the yearly world-wide production volume was around 10.5 billion units. The standard CD-R is 120mm in diameter and has a storage capacity of 74 minutes of audio recordings or 650MB of data. There is also the mini disc (80mm in diameter / 180MB) and the ever so popluar marketing tool, the 'business' card disc (58-68mm / 50MB ).
CD-R's are made of polycarbonate pellets, a type of thermoplatics, which provides transparency, stability, and is impact resistant. There are three basic steps that get applied to the polycarbonate disc once it has been pressed with a metal stamper to form a pre-groove or sprial track where the data will be stored.
The first step will be to add a very thin layer of organic dye on top of the sprial groove. This process is applied by spin coating. The second step adds a thin reflective layer of silver or gold. This is accomplished by a procedure called sputtering. The reflective layer is applied by magnetic bombardment of the silver or gold atoms which affix themselves to the disc. The last step adds a protective coating of a photo-polymerizable lacquer that is then cured with a uv-light.
CD-R's were made to last. The estimated life span, based on acelerated aging, ranges from 100 to 200 years. However proper care must be taken when working with these discs so as not to reduce the life span to only a few years. First and foremost the CD-R's recording surface that is modified by heat, to store data, can be susceptible to material deterioration. The data can actually shift on the surface making it unreadable to the laser. So try to burn at speeds of 4x or 8x (this will produce fewer errors), try not to multitask on your computer when burning, store the CD-R in a jewel case to protect the surface, and of course hold the disc by lightly gripping its edges.
One other useful bit of information is to only clean the disc if playback is affected. When you need to remove fingerprints, grease, dust, and or very minor scratches, rub toothpaste over the entire bottom of the CD. Let it sit for 30 to 60 seconds, then hold the disc under running water and use a circular motion to remove all the toothpaste. Allow the disc to air dry.