Label Printing: Silk Screening vs. Offset
During large-scale replication of CD-ROM’s and DVD’s, label printing is accomplished using one of two technologies, either silk screening or offset. Silk screening is the older of the two types of printing, while offset is a comparatively new method, which is gaining popularity. The actual process for each is quite different, and is explained below.
Silk Screening Process
Silk screening is a process where the label art is printed onto negative films, one film for each color used. The films are then transferred to screens that are mounted to a press. Imagine a window screen with holes left open for ink to flow through and plugged where there is to be no printing. The operator fills the press with the appropriate color, and an automated squeegee pushes the ink through the screen onto the disc. A color is applied, the press spins under a UV lamp to dry the ink, and then alternated between ink and lamp until each color has been applied and dried. This process creates dots of color that our eyes blend together to form the label image.
Offset Process
Offset printing uses a technology where plates are created either as above or directly from the artwork itself, again with one plate for each color used. The plates are etched at a higher resolution than silk screening, which allows more color control and finer detail. The plates are attached to a press, roll over an inkpad and then roll over the disk, thereby applying the ink.
Pros and Cons
There are advantages and disadvantages to both processes. Silk screening generally costs less, but has more limitations as it has a lower resolution than offset printing. This can become an issue when there are many fine details in the graphic chosen for the label. However, custom color matching is possible with silk screening, so that a color can be created using PMS colors, and metallic and fluorescent inks can both be used.
Offset printing is a little more expensive, but for color control and intricate or detailed artwork, it is a much better method. Another advantage is that because the offset is direct to plate, there is less prepress time. An added benefit is that the ink is applied in a much thinner coat, giving the disk a more smooth and consistent feel. Because of the higher resolution used, the label tends to have a more photographic appearance. On the downside, offset printing can dull slightly because of the higher resolution and also because the process inks are transparent.
Recommended Usage:
When matching PMS Colors, use SILK SCREEN
When you want high color, use SILK SCREEN
When you have heavy photography, use OFFSET
When you have detail work, use OFFSET
When there are people in the artwork, use OFFSET
When you want a matte color, use OFFSET
When you have very small text, use OFFSET
When you have gradients, use OFSET
For a complexly smooth finish, use OFFSET
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