CD Formats

Known by its abbreviation, a Compact Disc is a polycarbonate injection-moulded disc with a metal layer capable of storing digital information. The most prevalent types of compact discs are those used by the music industry to store digital recordings. This type of compact disc is read-only, which means that once the data has been recorded onto them, they can only be read, or played. The process starts with the making a glass master from which a stamper is "grown" using an electroplating process. Polycarbonate discs are replicated from this stamper, comprehensive bit-for-bit verification and other quality assurance measures are performed, and the discs are then ready for on-body printing and packing.

The process of making a CD-ROM is identical to the process of making CD audio discs; it is a polycarbonate injection moulded disc with a metal layer capable of storing digital information. The most common users of CD-ROM are the games and software industries, while corporate use (technical information, product brochures, annual reports, etc.) is growing rapidly. First a Glass Master is created from the master supplied, from which the stamper is made.

Discs are then replicated from this stamper. When the first discs comes off the presses, the master and a manufactured disc are compared in a bit-for-bit test, an automated process which checks every single piece of information on the manufactured disc against the supplied master. The disc will also be manually checked on a number of computers, and when the CDs have passed these tests, replication of the complete order will proceed, followed by on-body printing and packing

A screen is made of porous, finely woven fabric (originally silk, but typically made of polyester or nylon) stretched over an aluminum frame. Areas of the screen are blocked off with a non-permeable material - a stencil - which is a positive of the image to be printed; that is, the open spaces are where the ink will appear.

The screen is placed on top of the disc. Ink is introduced to the top of the screen, and a rubber blade(squeegee) squeezes the ink evenly into the screen openings and onto the disc. The ink is dried rapidly using infra-red light before the next colour is transferred.

Silk-screen printing is most effective for one or two spot colours, and is not very successful for full colour.

Litho printing is a widely used printing technique where the inked image is transferred (or "offset") from a plate to a rubber blanket, then to the printing surface. When used in combination with the lithographic process, which is based on the repulsion of oil and water, the offset technique employs a flat (planographic) image carrier on which the image to be printed obtains ink from ink rollers, while the non-printing area attracts a film of water, keeping the non-printing areas ink-free.

Litho-printing is mainly used for full colour and more complicated designs where the images need to be very clearly defined and gives superb results.

Ink-jet Printing

This is primarily used for short runs of CD and DVDs as set-up time and materials are minimal, thus reducing costs. When using industry-standard ink jet printers, as installed in All Write Media, the quality is excellent on full-colour artwork and photos, however, ink-jet printing is not ideal for spot colours or solid black images.