prepress

Prepress is the term used in the printing and publishing industries for the processes and procedures that occur between the creation of a print layout and the final printing. The prepress process includes the preparation of artwork for press, media selection, proofing, quality control checks and the production of printing plates if required. The artwork is quite often provided by the customer as a print-ready PDF file created in desktop publishing.

==Processes== thumb|Digital prepress thumb|Color matching thumb|Color swatches thumb|Imposition layout Binding selection gives the customer multiple options for the spine of the publication such as Saddle-stitched, Perfect Bound or Case Bound, also Spiral, Wire and Comb binding are possible. Each has its merits and suits a particular number of pages. Preparing artwork involves setting color profiles, bleed, registration and crop marks as specified by the printers, use spot colors, trapping and overprint as needed. Check transparency flattening results and allow for creep. Pre-flight is an automatic scan of the document using the printers pre-defined profile to find errors before submitting. Raster Image Processor (RIP) is the software/hardware that processes the print-ready files into a rasterized format that the printer can understand. Proofing involves creating an accurate copy of the artwork before beginning production runs. This serves as a bond between the printer and their customer that the final product meets an agreed-upon standard. Proofs in general can be done for all parts (images, illustrations, text and colors) of the print product. In this part, three types of proofing should be checked and printed out: the print-ready PDF files, the printer's proof and the imposition proof. Print-ready PDF files should be made after the layout using preflight at the printing house. The printer's proof should be printed out in high resolution and checked by the customer. The imposition proof, which is usually done by the printers, should also be printed out to check and adjust the printing press. Soft proofs are digital proofs that simulate accurately how the finished publication will look, intended to highlight any future issues. Hard proofs are physically printed proofs that simulate accurately how the finished publication will look, intended to highlight any future issues. A Contract Proof serves as the agreement between a customer and a printer which is signed-off before the printing can begin. This can be digitally signed as a digital contract using services like Acrobat Sign. Quality control is performed throughout the prepress process but especially after the proofs are produced. Imposition is the arrangement of the printed product’s pages on the printer’s sheet, in order to obtain faster printing, simplify binding and reduce paper waste. Computer to plate (CTP) uses a laser to burn the image from a computer file onto a printing plate. Plates are made of different materials, depending on the needs of the printing method, usually Thermal, Photopolymer or Silver-Halogen (violet) plates are used. They usually have a processing stage in chemicals or liquid although process free plates are available.