The Difference Between Duplication and Replication
Disc Replication
Replicated discs are created from a glass master, stamper, injection moulding line and specialised offset or screen print machines. Given the substantial setup costs involved, the minimum run size is 500 units and the price typically drops for higher quantities, especially 1000+.
Replicated discs are subject to stringent quality control checks at all stages of production. In the first instance, master disc data is loaded onto a hard disc drive and compared to industry standard formats, to determine whether the data fits one of the accepted standards.
Once the data is passed for replication, a glass master and stamper are produced. The stamper is then loaded into a hydraulic press. Optical grade polycarbonate is then fed into the machine and the discs molded under high pressure to create substrates. These substrates are metalized and lacquered, then passed through additional readability quality controls before being printed. The cycle time is generally around 2 to 3 discs per second depending on the line.
Discs are then printed using one of the high quality, high speed commercial print techniques (offset or screen).
This replication technique is used for virtually all commercial release DVDs and compact discs.
Disc Duplication
As a short run alternative, data can be copied from a master DVD or CD to a blank recordable media, typically DVD-R or CD-R. See the quick jump section for a full list of recordable media.
Multiple burner stations (or racks) are used by commercial duplicators to simultaneously burn multiple copies of a title onto discs. Depending on the sophistication of the setup, these multiple burners may have an auto load station which feeds the blank discs into the burners.
Before the blank discs are recorded, they are typically passed through an inkjet, thermal or some other printer to print the disc face. Printed labels are also used on occasion.
Which to Choose?
The advantage of duplication is that the setup time and costs are minimal. A duplication run is typically anywhere from one disc (e.g. burning on a home pc) to two or three hundred discs. Print techniques are improving also, so it is now possible to print a reasonable quality image onto the disc, depending on the quality of printer used. The turnaround time for production is also much quicker, with high speed facilities able to produce many thousands of discs each day.
The disadvantages of duplication are as follows: (i) the quality of the blank media can vary, which can result in unplayable discs (ii) the recorded discs do not play as reliably in some burners, especially older burners that would otherwise play a replicated disc (iii) the lack of quality controls at glass mastering could create a non standard disc that cannot be read by the intended player, (iv) the prohibitive cost of producing larger runs (duplicated discs are usually double the cost of replicated discs once you get above 500 units) and (v) the offset and screen print quality available for replicated discs is far superior (in terms of resolution and colour accuracy) to the short run print techniques. DVD-R blank media in particular is very unreliable in many players and should not be used for a commercially released DVD project.
The appropriate type of manufacture (pressing or duplication) will depend on the size of the project, the time available and the intended market (giveaway or retail sale). However, if it is possible to replicate the disc then this is clearly the superior production technique and the only technique used by Hollywood studios, commercial record labels and other commercial project developers.
