Replication and duplication are terms referring to how your CD or DVD discs are manufactured. The words duplication and replication may seem interchangeable, but they are very different.
Duplication is the process of taking blank, recordable discs (CDRs or DVDRs) and writing the information on them with a laser. The laser beam burns the organic dye so that some parts reflect light and some are absorbed. Duplication is best for short runs under 500pcs.
Replication is the process of creating a glass master from your data CD Audio, CD-Rom, or DVD video. Over a series of many steps, a nickel stamper is created from the glass master, then placed in an injection molding line. The optical grade polycarbonate is molded to the stamper, creating a clear substrate that contains your data. The substrate is then metallised, lacquered, then either CMYK offset printed or screen-printed. The process can take 2-3 weeks depending on the project. Replication is best for larger run starting at 500 pieces or more.