"Standard Commercial DVD's are pressed and literally stamped out at the rate of 700 or more per hour. DVD±R's are instead "burned" one at a time on stand alone DVD-R burners whereby a dye layer is "burned" by a small low power laser. Thus a DVD-R is constructed quite differently than a commercial stamped DVD.
A DVD-R will have a dark greenish - Blue appearance on the recording side, which is the dye layer. A stamped DVD has no dye layer and will appear shiny. Thus a DVD-R has a much lower reflectivity than does a standard DVD."

"Those DVD's are "replicated" and the data is actually stamped into the DVD's during a complicated manufacturing process. However, the same chemical burning process used by our desktop DVD burners is also used by some companies that will make mass copies of your DVD project: instead of replicating them with the stamping process, they duplicate them in machines that can burn several copies at once. The difference between burning - or duplication - and replication can be critical."