Prepress is the term used in the printing and publishing industries for the processes and procedures that occur between acceptance of a written manuscript and original artwork, and conclude with a printing plate, image carrier, or (traditionally) forme, ready for mounting on a printing press.

During the 1980s and 1990s, electronic publishing techniques largely supplanted the traditional processes, and as of 2004 the word prepress has become almost synonymous with digital prepress .

The processes of copyediting, markup, proofreading, typesetting of text, photography of artwork, retouching, screening (of continuous-tone images such as photographs), trapping (also referred to as spreading and choking), page layout, page assembly ("stripping"), imposition (combining of many pages into a single signature form), and photomechanics (exposure and processing of a photomechanical printing plate) are all considered part of prepress, and are largely common to traditional and digital prepress. Some prepress processes specific to digital workflows include preflighting (verifying that all files needed are present and valid), color management, and RIPping.

The specific processes used in a particular printing application are called workflows and, of course, vary, depending on the printing process (e.g. letterpress, offset, digital printing), the final product (books, newspapers, product packaging), and on choices of technology.

Before computer layout and design, the prepress stage used a large format camera to make plate or bromide of the completed text and images. Computers now rasterise the completed layout with either lasers or thermal diodes to a plate in a Platesetter, this is referred to as Computer to Plate (CtP).