This article is from the CD-Recordable FAQ, by Andy McFadden (firstname.lastname@example.org) with numerous contributions by others.
If you've ever looked at a recorded CD-R, you've probably noticed that
the recorded and unrecorded areas have a different appearance. This is
usually visible as a slight change in color. By controlling the write
laser it's possible to mark the disc in a way that is meaningful to the
human eye rather than to a CD player. Unfortunately, the level of control
required to do this isn't achievable without firmware support.
In mid-2002, Yamaha announced "DiscT@2" (disc tattoo). This allows
moderate-resolution (approx. 250dpi) graphics to be drawn in the parts of
the disc that weren't recorded. Yamaha claims to get 256 shades of color
(green, blue, or whatever color the disc happens to be), though it works
best on dark blue azo discs. For more details and some pictures, see:
Yamaha left the consumer CD recording market in February 2003, and the
technology quietly disappeared.
In March 2004, HP announced a different idea: flip the disc over, and burn
a design on the label side. This requires a modified drive and special
media, but offers the possibility of high-resolution labeling without ink
or adhesive labels. The technology, dubbed "LightScribe", is described