PREPRESS TERMS

 

Bleed: Artwork which extends beyond the edge of the trim area of a print piece. The purpose of bleed is to safeguard against unsightly results that might otherwise be created should the piece be trimmed slightly beyond the intended trim area due to machine tolerance or human error.

 

Color Separation: The process of separating artwork into the component printing colors to be used in production, most often the four process colors: Cyan, Magenta, Yellow and Black, for later recomposition on press. During separation, continuous tone artwork is broken down into tiny dots through the aid of line screens to be specified by the printer.

 

CMYK: “Cyan, Magenta, Yellow, Black”’—A color formulation standard, used for print production.

 

Creep: The phenomenon by which spreads in the middle of a thickly bound piece, especially bound by saddle stitching, tend to “creep” out from the center fold line of the piece due to successive layers of spreads bound together. The result of creep may include the outer edges of middle pages being inadvertently trimmed off in an unattractive manner. Creep should be accounted for in prepress by adjusting layouts either manually or via imposition software.

 

CTF: ‘Computer to Film’—A process by which color separations are made from computer to Film, from which printing plates are then burned using a refined photochemical process. Advantages include the control afforded by seeing wet proofs made from film, examining films for problems with Moïre patterns and Overprints, the ability to strip in or strip out corrections or remake films affordably, and—In China—lower cost. Disadvantages include the potential loss of quality due to one additional transfer step and the extra time required to make films.

 

CTP: ‘Computer to Plate’— The process by which color separations are made directly to printing plates from digital files, without the aid of an intermediary step. Advantages include quality afforded by eliminating the intermediary step, speed and convenience. Downsides may include an inability to identify problems with Moïre patterns and Overprints, the usual omission of accompanying wet proofs, which might allow identification of costly mistakes before press time, and—in China—higher cost.

 

Digital proofs: Proofs made by a proofing method such as inkjet, color laser, dye sublimation, or thermal wax to produce an approximation of the color to be expected in the final product.

 

DPI: “Dots Per Inch”— The print industry standard resolution metric. For printing in China, image files should be 300 dpi.

 

ICC Color Profiling: “International Color Consortium” profiling—A Universal color management specification created to allow color management across various platforms and vendors.

 

Live Area: The area inside the trim lines; The area of artwork intended to be included in the final work.

 

Moïre Pattern: An unsightly criss-cross pattern created when previously printed material has been scanned and color separated once again, resulting in a conflict of screen angles.

 

Overprint: The process by which a color, quite often black due its density, is surprinted on top of a previously printed color area. For instance, small black or other dark type laid over a lighter color in a design, should normally be overprinted, to avoid registration problems on press. When providing PDF files, designers should ensure that the overprint setup is as desired, as it will be difficult in the preflight stage for China Printing Solutions to make changes to such setup.

 

PDF: “Portable Document Format” —A file format developed by Adobe which permits linked images, fonts and color profiles to be embedded in a single file which may be opened and sent through a RIP for color separation without the native software package used to create the original file. Extremely advantageous for avoiding inadvertent prepress errors, but difficult to change. Customers providing PDF files should be skilled in their creation.

 

Printer’s Spreads: A page layout configuration which is arranged in the order most convenient for printing, where up to 16 pages are generally imposed together on a single large printing sheet.

 

Reader’s Spreads: A page layout configuration which mimics the final order of pages as will be seen by the reader in the final piece.

 

RGB: “Red, Green, Blue”—A Color formulation standard commonly used for viewing art on a computer monitor.

 

Trim: The point on each side of a printed piece at which the artwork is intended to be cropped.

 

Wet Proofs: Proofs made by real printing ink, generally on the paper to be used on the actual print run. Wet proofs in China are run on hand presses using temporary mylar plates and, while they may still exhibit discrepancies in registration or pressure-induced color shifts, are considered by many to be the closest sensual equivalent to the final product possible. Ideal for checking crossovers, construction, overprints and bleeds.