This is to just share information. cheers
Basically, ROM are professionally done by a Media Manufacturer, and are of better quality, and do cost more to produce, as the MOQ is rather high & have a Stamper Fee. Most of these professional shops have strict Quality Checks, from verifying the Master, producing the Glass Master & the stamping & label printing process. Lots of automation, so less human finger prints on the Media. Less handling, less scratches.
R media (Recordable) can be done by anyone with an appropriate burner & software (single copy). For multiple copies, most Duplicating Towers can do COPY as well as COMPARE the duplicated medias vs the Original in the "Master Drive" if this option is selected prior to copying. But by doing so, the copying time is pretty much doubled.
Most places do not do an "Analyze Test" to grade the quality of the Originar Master Disc or the copied R media as far as readability/playability. NOTE - The copies can never have a higher Grade than the Original. If the Original is a grade "C", the target copies can never achieve an "A or B" Grade. (Grade A is the best quality).
The Faster the Copying Speed used, will normally result in a lower grade copy.
The brand & specifications of the R media also plays a big part on the quality. Avoid using extremely cheap R media, we have found majority gives us a D grade. Still playable/readable, but ....... ?
R media also do not last as long, that is why it is good to back it up, provided there is no "protection", otherwise you will need to do some extra effort to back it up to HD.