The difference between compact disk (CD) replication and CD duplication is that replication is a professional process that creates a CD by molding the disk to be an exact copy of the original master. Data cannot be added or changed in this case. Duplication, on the other hand, refers to burning data to a disk, as is done in home computing.

Duplicating CDs for personal use is inexpensive and convenient, making it the better choice for low-run needs. CD burners and popular software both do an admirable job of duplicating audio tracks or data files to CD-R (recordable) or CD-RW (read/write) disks.

However, there are instances when replication is a better choice. For example, if you have mastered a CD of original music and would like to make 500 copies or more to send out as promotional material to national radio stations, music labels, and talent scouts -- or to sell at gigs -- replication will be cheaper and will ensure a durable, reliable copies of the highest standard. Replication will also include label art and packaging, giving your CDs a professional look.

In CD replication your original master is used to make a glass master which in turn allows a set of stampers to be made. High-tech injection-molding makes exact clones of the master, using the stampers. A coat of reflective aluminum follows, sealed with a protective coat of lacquer hardened by ultraviolet light. Every CD is made in this fashion, essentially a first generation replica. From here the disks pass through a printing device for label artwork.