Offset CD/DVD Printing
The Offset printing method combines ink and water to stamp artwork and text onto the surface of a replicated or prerecorded CD, DVD or Blu-ray disc. The concept of offset disc printing is similar to lithography as well as newspaper and magazine presses. Offset printing produces images at a resolution of approximately 175 dots per inch (dpi). This process is usually performed by professional printing or media duplication and replication services.
The photographic results of an offset CD, DVD or Blu-ray image are derived from its use of a CMYK ink system. This color spectrum stands for Cyan (C, or blue), Magenta (M, or red), Yellow and Black (which uses the letter K to prevent mistaken identity with blue). Within this spectrum there are an infinite number of color possibilities and combinations to choose from.
Before actual printing begins, the offset equipment may lacquer the CD, DVD or Blu-ray with a white flood coat, also known as a white overcoat. This layer functions as a primer base that lays the groundwork for easier and more accurate color application. This coat also functions as a neutral foundation to prevent all or partial areas of the silver disc reflection from being a part of the design.
Offset disc printing equipment uses four machine plates that are each applied with an ink color of the CMYK system and another plate for spot color. The original image intended for the disc is applied to each of these plates after encountering a chemical procedure that functions similar to the science behind photography. This results in a reverse image that rests on the plates.
After each plate is inked with its unique image information, they are blanketed with a rubber layer which is then affixed to cylinders. Subsequently, each cylinder of single colors from the CMYK system are rolled or transferred (offset) onto the disc one at a time. Therefore, the reverse image that was applied to the plate is restored to its proper orientation when printed to the disc. The result is a four-color printed image with a matte finish.
In addition to CMYK ink, water or a water-based film may be applied to the plates. This serves to draw ink away from disc surface areas that must remain blank or without color because of the nature of the image. When ink and water are used together, the effect is similar to oil and water.
There are a number of advantages to choosing offset printing for CDs, DVDs or Blu-rays. Due to its nature of high resolution and countless color variations, offset reproduces photographic quality images and intricate color patterns with vibrancy. The matte finish remains smudge-proof and virtually scratch-proof. While silkscreen uses a fine mesh screen, offset printing uses plates. This processing method translates to a more evenly covered, smooth disc surface where fine mesh screen marks cannot be traced.
Offset printing is intended for high-volume or replication disc orders. When it comes to thousands of copies, offset disc printing is quick, highly efficient and economical in such bulk quantities. However, like silkscreen printing, the professional fees for equipment setup costs do not justify the expense for the majority of smaller volume or duplication orders. Offset printing generally takes several business days to complete since it is associated with higher volume disc orders as opposed to other printing methods.