Printing is a process for mass reproducing images and texts. It is used in a wide variety of industries and applications, from books and magazines to advertising and transaction printing.
Traditionally, printing is defined as a process for reproducing color or black-and-white illustrations on a durable surface. Various techniques are employed to reproduce such images.
Before the introduction of electronic page making systems, printing was carried out using photomechanical methods. Before modern processes, which use highly specialized photographic materials, the print industry depended on mechanical concepts of pressure and coloring agent.
Since the late 20th century, the printing industry has developed away from lead types and ink to offset and computer-based techniques. However, printing is still an essential part of paper-based publishing.
Among the different processes, the two dominant printing technologies are offset and lithography. Offset uses opaque inks. The ink is applied to a blanket cylinder, which is then transferred to the paper. During the process, slight variations in registration occur, which can result in white space at the edge of the printed piece.
Another technique of indirect printing is letterpress. Letterpress is used for fine editions of books and business cards. Unlike offset printing, which produces a single copy of the work, letterpress produces two copies of the piece.
The printing industry is also heavily reliant on specialized photographic techniques and equipment. Such methods include microfilms and punch tapes. These devices preserve a large amount of information in a small, flat, and convenient form.