Why do I need a DVD replication check disc?

A replication check disc is "pressed" with the actual DVD replication press, and it is created with the same glass master that will be use to press the rest of the project.

It is the only safe way to proof a replicated CD/DVD, because all the CD-R or DVD-R that we can create from computer & recorder are "burned", which is a different process than replication, in which the discs are pressed. A check disc is especially important to check the layer break of a DVD-9 project