Blu-ray Replication
Blu-Ray replication is the process which most Blu-ray disks (BDs) are made. Replication involves making a glass master from the digital audio, video, or data that will be on the disk.
This glass master has the shape of the pits and lands that are used to store the data on the disk. The glass master is used to make a metal stamper, which is a negative image of the BD.
The stamper is used as part of an injection molding machine to impress the shape into liquid polycarbonate as it cools inside the mold in a process called “coining”.
The polycarbonate disk is then coated in aluminum in a process called sputtering to reflect the laser beam of the reader so the disk can be read. The disk is then coated in lacquer to protect the data from scratches and oxygen.
If the BD is multi-layered, the other layers will be embossed into the lacquer which will then be sputtered with a semi-transparent layer of aluminum, then coated in lacquer again.
This process is repeated for each layer of data. A second type of lacquer (TDK® Super Hard Coat) is applied last to give it extra scratch resistance.
The BD is made to extremely tight tolerances for flatness, and this includes the lacquer layers. Then, finally, the BD is printed with a label. BD replication is the most efficient way to make a large number of identical BDs. The BDs produced by replication last much longer than duplicated disks.
Blu-ray Duplication
Blu-Ray disks may be duplicated by “burning” a copy of the information from one Blu-ray disk (BD) onto a recordable BD (BD-R). A laser in the recorder melts a pattern into the recordable disk that mimics the pattern of pits and lands found on a replicated BD.
BD duplication is good for making a small number of copies of a disk, but is not well suited to making large batches of BDs. Duplicated BDs do not last as long as replicated BDs, and are more prone to be damaged by things like sunlight or heat.