Silkscreen printing is a process that prints text and illustration on the top surface of CDs, DVDs, Blu-ray and other replicated or recordable discs by employing centuries-old techniques. The basic concept of general silk screening is pressing ink over a stencil with a roller and allowing the ink to spread across the desired surface through a fine mesh screen that rests below the stencil. Silkscreen disc printing is typically handled by professional media duplication or replication services.
The process for silkscreen printing on CD, DVD and Blu-ray discs is nearly identical to the processes developed hundreds of years ago. The disc rests in a tray of the automated, robotic silkscreen machine. Up to 5 spot or Pantone Matching System colors of specially lacquered ink are precisely measured and dispensed. Using too much ink will cause it to drip and spread an excessive amount which could therefore ruin the artwork or text.
Silkscreened discs also use a white undercoat, also known as a flood coat. These coats of white ink are like disc primers that are layered on prior to the application of the image and text. It provides a foundation which results in more accurate color usage. White undercoats and flood coats also function as a neutral base to prevent all or some sections of the silver disc reflection from showing through.
Next, a roller-which functions much like a household paint roller-smoothes the premeasured ink across the disc over a plastic design stencil and through open areas of the fine mesh screen. After each coat of ink, the disc rotates to account for ink drying while a new layer is applied by the roller. Following the ink rolling, the discs may be treated under an automated silkscreen machine's UV lamp for a damage-proof finish.
An alternative to a stencil is also used in silkscreen disc printing. Layers of photographic film in their individual colors can be geneated based off of a user's artwork to block parts of the mesh screen in order to comprise the image produced by the application of ink with the roller.
The print resolution (and therefore the quality) of disc silk-screening ranges between 80 and 200 dots per inch depending on the quality of the screens used by the printer.
The silkscreen process has a few advantages. It is a cost-effective method for high-volume CD, DVD or Blu-ray orders. For discs that require solid color surfaces or vector text and images, the silkscreen technique can provide the highest quality color matching as well as crisp text. One can also maximize the use of the disc's surface area, as images can be printed to the very edge of the disc.
One major disadvantages of the silkscreen disc method is that the lower resolution is not well suited for raster graphics such as photographs. This limits the type of disc artwork that can be used when compared with other print methods such as inkjet. Additionally, the high setup costs for silk screening do not justify its use for small duplication orders.