Orbit II Disc-to-Disc Copier Reference Manual – Revision J
6
Section 3 — CD-R Media Recommendations: (cont.)
Although you cannot select CD-R media based upon color alone, there is a correlation between
“reflectivity” and media performance. The CD or CD-R drives that read the CD-Rs you duplicate project a
laser beam through the thickness of the plastic disc. The laser beam is reflected by the metallic coating on
the back of the CD-R and returns through the thickness of the plastic to the drive’s optical detector. For
CDs, the minimum reflectivity specification is 70%. CD-Rs are permitted to have slightly less reflectivity.
Their minimum specification is 65%. Hold a commercial CD up to a light. Place your fingers a few inches
behind the CD. You will typically not be able to see the shadow of your fingers looking through a CD. For
CD-Rs to work in a large number of CD or CD-R drives they should have similar reflectivity and opacity.
Reflectivity and opacity become increasingly important as read drive speeds increase. A modern 52x read
drive requires more reflectivity than an 8X read drive. It is best to avoid CD-Rs that are less reflective
and/or opaque than the CD-Rs you are using as your reference sample.
CD-RW media has about ½ of the signal strength of CD-R media, even though they may appear to be
highly reflective. The lower signal strength of CD-RW media is one of the reasons they may not work in
older CD-Audio, CD-ROM, or CD-R Drives. Recognizing the need for CD-RW compatibility, Compact Disc
media and drive manufacturers met and established a specification that is intended to assure CD-RW
interchange capability. Products compliant with this new specification carry a “MultiRead” qualified label on
their faceplate, or in their product manual. CD-RW media should only be used in CD-Audio, CD-ROM, CD-
R, or DVD Drives that have MultiRead certification.
