CD-RW ASAP

CD Media: Rainbow of Media

Gold, silver, blue, green... How does color affect the longevity of CD recording media--and the integrity of your data? Read on.

A CD-R disc has a reflective layer and a dye layer. The composition of the reflective and dye layers might influence the disc's longevity, but considerable debate persists over which combinations will last longer, and for how long. Accelerated life tests--necessary since CD-Rs have been around only for the past decade--suggest that a CD-R disc will last between 60 and 100 years at room temperature, inside a dust-free jewel case, at normal or low humidity, with no exposure to UV rays or sunlight (which can cause the dye to fade).

The color of the disc's writing surface will vary based on the combination of the dye and the reflective layer used. While many experts believe that a gold (colored) reflective layer will last the longest, few vendors use gold any longer--except in their premium discs. Today's silver reflective layers are considered by many to be as good as if not better than gold. A silver reflective layer is less expensive to produce, and it has a higher reflectivity value than gold, making it inherently more compatible with the lasers currently being used in CD-RW drives.

The vast majority of CD-Rs sold today use a silver reflective layer and phthalocyanine dye. (Some disc manufacturers use a silver reflective layer with silk-screened gold coloring on top of that.) Also popular are cyanine dye and Azo dye (distributed by Verbatim and used in the mass production of DVD-Rs).

The latest manufacturing trend is to make CD-Rs more fashionable by producing them in different colors, ranging from bright red to sleek black. Disc producers start with a colored plastic disc and then apply the reflective layer and the dye to it. Opinions differ as to whether colored media will affect the reliability and longevity of the disc. Black discs are generally accepted to be on par with standard silver discs in both reliability and longevity.

Reusable CD-RW discs have a shorter life span--estimated at 30 to 50 years, if you record to them many times. But they're more rugged than CD-R discs: Their phase-change dye layer renders CD-RW discs less sensitive to light and heat than regular CD-Rs.