Offset Printing

Offset printing, or "offset lithography," reproduces flat images on the paper. It is the most common form of printing.

The printing plate is coated with light-sensitive emulsion. The plate is exposed to the images to be printed, much the way film in a camera is exposed to images. The image areas on the plate are treated to attract ink and repel water; the non-image areas are treated to repel ink and attract water.

The plate is inked in the press and the image is "offset" from the plate to an intermediate blanket that, in turn, prints the image on the paper. Offset printing is simple and does not have any of the tactile qualities of the other forms of printing, such as engraving, embossing and letterpress. Yet it is very versatile.

Applications
Offset is characterized by its faithful reproduction of images, such as color photographs. It prints well on a variety of papers, and accurately renders halftones, screens, solids, shadings and patterns. It is also economical for any size run and virtually any format, such as booklets, brochures and posters.