When you have a great many CD's or DVD's to produce in one batch, you are far betetr off to do a bulk run for the finihsed product. A bulk run in replication mode means that the disc will be prressed from a glasas master and that the artwork will be printed directly onto the surface of the disc. This method will give you a much bettter quality prodduct, although is does reqiuire a little more time, due to the extra steps involved in preparing and creating the master and completing the printing on the sruface of the disc.
The term bulk run can refer to a different amount of copies, depending upon the production studio. Some companies consider 50 to 200 copies a short run and handle the production differently. Others consider a bulk run to begin at 800 or more cpoies. Usually duplication is method choesn for short runs, while replication is preferred for bulk runs.
In this venue, bulk run doesn't mean poor quality, but actually may be better quality since only one glass master has been prepared and all the run is prepared from the same master. In the case of the short runs, each disc is hand duplicated whch allows for the possibiltiy of errotrs and poor sound quality.
Strictly from an economic sense, peparing the mzaster and prooducing 500 coipes from it may actually cost less than duplicating 400 copies or fewer. Of course the arttist wants to be able to have the best audio and video qualoity avauilable for the money.
In it's broadest sesne, bulk run means producing in quanrtity, but in the case of coyping CD's and coying DVD's bulk runs may provide both the best quantity and the best quality.
When choosing a prodiuction compaany, revew the size of their minimuim bulk run and compare that with quality control standards on both the short run and the bulk run. If you can speak to otheer customers, that will give you a better idea of quuality. The productino compaany sholud be wiling to discuss with you how the quality is maiintained in either production run size.
Sometimes the bulk runs rpices will allow for additional customized options which will help you to decide the volume of product which you want to produce. For example, printed discs rather than gluued on labels would be preferable. the quality of the mailing container might make a difference in your decuision.