The Manufacturing Process
The process of manufacturing a CD, DVD or Blu-ray begins with a data disc master. A data master (also known as disc master) has the program (either digital CD audio or computer files) as it will be on the manufactured disc.
This disc master is used to make a stamper (typically a nickel alloy) that has the inverted pattern of pits and lands, which contain the data. This stamper is attached to one side of a split-cavity mold.
Molten polycarbonate is squeezed into the mold at precise speed and pressure, then cooled. As the polycarbonate cools, additional pressure is placed on it by the mold cavity, pressing the pattern of pits and lands into the top-surface of the disc.
For a good data disc master:
- Check, double-check, and triple-check your files! Once a stamper is made, it cannot be changed. If you find errors after the stamper is made, a new stamper will have to be made!
- Use standard file formats for data discs. Avoid using exotic or proprietary files formats where possible to promote end-customer satisfaction.
- Burn data disc masters to high quality recordable media using DAO (Disc-At-Once) write mode ONLY. Do NOT use TAO (Track-At-Once) or SAO (Session-At-Once) modes. Although a stamper can be prepared from these, it requires additional processing and prevents bit-to-bit comparison of the replicas to the data disc master. A good alternative is to use a disc image in a standard format (DDP, ISO (DVD or data CD), or BIN/CUE (CD Audio) stored on removable media such as flash drives or cards (a DDP image is, in fact, ideal.) Checksums can be made to ensure data integrity.
- If using recordable media masters, ensure that the write session is “closed” when completed.
- Normalize audio tracks before mastering.
- Check your DVD menus thoroughly to ensure that they are easy to navigate and work properly.
- Try to keep CDs to less than 650 MB (74 minutes of audio) and DVDs to less than 4.7Gb (DVD5) or 8.5Gb (DVD9).
- Although modern recordable media sometimes have much higher capacities, the ISO standards were written for the above capacities. Discs exceeding these recommended sizes may not conform to readability standards and consequently, may have slight to severe readability issues.
- If distributing .pdf formatted files, it is recommended to include the freely distributable Adobe Acrobat reader so that end-customers can install it if they do not have a .pdf reader. Freely distributable readers for most other file formats exist as well and should be considered for inclusion where appropriate, especially if unusual or proprietary file formats are used.
- Check your data again, you can never be too certain.