15th EditionAppendix A: Design and Production—Basic Procedures and Key Terms
The most common type of printing used to produce books and journals is offset printing, or offset lithography. This process involves the transfer of images (text, illustrations, and any other marks that will be distinct from the background color of the page) from the printer’s plates to the paper through an intermediate cylinder. The printer applies ink to each plate, and the inked images are offset onto the paper through the rubber-blanketed intermediate cylinder (see fig. A.10). The printing press itself may be either sheet-fed, using sheets of paper that have been precut, or web-fed, using rolls of paper that will be folded and trimmed at the end of the printing stage.
A newer method, digital printing, uses technology similar to that of the traditional photocopier, in which images are printed directly onto paper through ink jets or thermal transfer. The quality of the reproduction is generally not as high as that achieved through the offset process. But digital printing makes it economically viable to print small quantities of a publication (three hundred copies or fewer) on demand, preferably from archived electronic files, and can assist publishers with inventory management.