Dissecting a CD for Design Sake
The individual parts of a compact disc provide unique graphic
design challenges and opportunities for desktop publishers and
designers. In this article we dissect a compact disc and analyze
its manufactured anatomy, explaining how the different parts
will affect your disc design. Knowing the medium you are
designing for helps prevent unwelcome surprises in the final
product.
Main printable area
The main section of the disc: This is where the audio or data
is encoded. Colors printed on this surface will tend to appear
darker than they would on white paper. Depending on the ink
coverage, differing amounts of the silver surface will show
through. Higher ink coverage (darker colors, in general) means
you'll see less of the reflective surface showing through. Less
ink coverage, with print dots more spaced apart (lighter colors,
in general), will reveal more of the underlying disc surface.
The only way to have something appear white anywhere on the disc
surface is to print with white ink (see "white base coat"
below).
Mirror band
This is the ring area just inside of the main print area. The
mirror band is not encoded with data so it has a different
reflective quality, appearing darker than any other part of the
disc. Generally the mirror band is etched with the name of the
manufacturer, as well as a number or barcode identification
associated with the client audio master. The effect of printing
on the mirror band is a darkening of the text or images as
compared to that of the main print area. Just inside of the
mirror band is the stacking ring.
Stacking ring
On the underside of each disc, this thin ring of raised plastic
is used to keep a small amount of space between each disc when
stacked up for boxing and/or shipping. It prevents the flat
surfaces from scraping against each other, which could scratch
either the printed tops or the readable bottoms of the discs.
Even though it is on the underside, some manufacturers are
unable to print over the stacking ring area due to a small
"trough" created on the top surface when they mold their discs.
Other manufacturers mold discs that are smooth on the top and
have no problem printing over the stacking ring area.
Hub
This is the innermost portion of the disc, made of clear
plastic, and includes the stacking ring. Printing over the hub
area is similar to the effect of printing on transparency media.
The lighter the color, the more the transparency effect is
present, due to the small, widely spaced print dots that are
used to produce light colors. With heavy ink coverage over the
hub, the transparency is far less noticeable. However, all
colors will appear different when printed over the clear plastic
hub as compared to the other opaque surfaces of the disc.
A Basic Solution to the Inconsistencies
Applying a white base coat over the disc's entire print area
before printing the design lessens the darkening effect of the
mirror band, and also lessens the transparency effect of the
plastic hub. The white base (sometimes termed "white flood")
acts like a primer coat, so the final design more closely
resembles printing on the white paper of standard jewel case
inserts, wallets, posters etc. If your cd design includes
photos, particularly faces, a white flood will make them look
more natural. It can also help to match colors used on the
printed inserts. Most manufacturers will not automatically
suggest a white flood, and they may charge for it as they would
any other ink, but it can make a big difference in the
appearance of your designed disc.
Professional design encompasses much more than manipulating
images, text and colors with computer programs: Even the most
carefully chosen typeface won't communicate effectively if
visually lost over the different areas of a printed surface;
clouds or snow on a cd design will be white only if you use
white as one of your printed colors. The characteristics of the
tangible item you are designing for play a critical role in the
overall design process. The compact disc is no exception.
Knowing its anatomy helps make better design decisions, and
better designers.