CD-R blanks that can hold as much as 84 minutes of Red Book sound (see the next section) or more than 700MB of data are made of a polycarbonate core coated with layers of reflective metals and special photo-sensitive organic dyes (see Figure 14-3). During the burning process, laser light hits the layer of dye, bakes it, and forms a pit. A 74-minute CD-R disc contains 333,000 sectors * 2048 bytes / sector for a capacity of 650.4MB. An 80-minute disc contains 360,000 sectors * 2048 bytes / sector for a data capacity of 703.1MB.