Accordion Fold: A term used for two or more parallel folds on a printed piece, that allow it to open like an accordion.
Acrobat: Adobe software that creates and reads files in the PDF Format.
Additive Primaries: In Color reproduction, Red, Green and Blue (RGB). When added together in equal parts, these three primaries produce white light on a computer monitor or television screen.
Aqueous Coating: A printing coating sealant that increases optical gain on the printed sheet. In offset printing, a special press unit prints the overall coating followed by an extended delivery dryer. Compare with varnish.
Basis Weight: The weight in pounds of 500 sheets of paper cut to a given standard parent size for that grade. For example, 500 sheets of 25 x 38″ 80# book weighs 80 lbs. Different paper grades are calculated from different parent sizes, for example copier paper weights are based on 11 x 17″ sheets.
Bleed: An extra amount of printed image which extends beyond the trim edge.
Bond Paper: A grade of writing or printing paper; typically used for letterheads, business forms, etc.
Book Paper: A general term for coated and uncoated paper in a weight suitable for books.
Caliper: The thickness of paper expressed in thousandths of an inch.
CMYK: The subtractive primary ink colors Cyan, Yellow, Magenta and Black (Key) used in Process Color printing.
Cookie: A cookie is a piece of data stored on the user’s computer. By setting a cookie on a user’s computer, we are able to link that user to their uploaded files for the purpose of producing print jobs.
Coated Paper: Paper having a surface coating which produces a smooth finish.
Cover Paper: A term applied to heavier-weight papers, often used to add substance to a printed piece, and for covers of catalogs, brochures, booklets, etc.
DPI (Dots per Inch): A measure of the resolution of a screen image or printed page. Dots are also known as pixels. 300 dpi means that there are 300 dots per square inch. Also known as PPI (pixels per Inch). Photographic images and other half-tones in printed material print at a certain line screen, often 150 lines per inch. The digital file should have roughly twice as many dpi as the line screen, in this case 300 dpi.
EPS Encapsulated PostScript® File: A portable, device-independent file format which allows Postscript data to be stored, edited, cropped, resized, and viewed on screen. An excellent format for transferring files between compatible applications. Most publishing applications support EPS. EPS files can include both vector and raster information.
Gripper Edge: The leading edge of the paper as it passes through the printing press.
Gripper margin: The unprintable edge of paper on which the grippers clamp as the sheet passes through the press.
Grippers: Metal fingers that clamp on paper and control its flow through the press.
Halftone: When reproducing a continuous tone image using a printing press, the image is broken down into small dots to emulate the continuous-tone look. See line screen.
JPEG (Joint Photographic Experts Group): File format which uses a “Lossy” compression method to create the final file. This means that the final image is not the pixel-by-pixel equivalent of the original, but is compressed, so file size is smaller.
Line Screen: The number of halftone dots per inch in a printed image. Often 150 lpi, although this varies depending on the printing method.
Overprint: The process of printing one ink on top of another. Black type, for example, often overprints images below it.
PDF (Portable Document Format): Introduced in 1991 by Adobe Systems, Inc. PDF is a file format designed for universal document communication across a wide variety of computer platforms, operating systems and networks, and printable on any modern printer.
PMS (Pantone Matching System): Pantone is best known as the company that produces color references for selecting, specifying, matching and controlling both Spot colors and CMYK colors.
PostScript®: A page description language developed by Adobe Systems to generate complex pages using a series of written commands, allowing for text and graphics to be rendered with mathematical precision and device independence. Properly created PostScript files should render the same when output to different PostScript-compatible devices.
Preflight: The process whereby files are checked for correct components before being submitted to print. Components include fonts, graphic files, color format, positioning within crop marks, etc.
“Preflight is the process of checking digital files for potential errors prior to output (Exporting to PDF or Printing). This process should be done on native or source file types, such as Adobe InDesign, Illustrator or QuarkXPress, everytime before saving or sending the job onto another party. Postflight is checking the resulting PDF, which is also a real must in the print-media workflow.” (comment by David, Markzware, define preflight).
Process Colors: The subtractive primary colors (Yellow, Magenta and Cyan), plus black (K), used in four-color process printing. Nearly all full color printed matter (brochures, magazines, etc.) are printed using process color.
Raster Information: The representation of images as a collection of pixels (dots).
Resolution: see DPI.
RGB: The additive primary colors Red, Blue and Green, used in phosphors of display devices and scanners.
Rich Black: A Black color in printing that includes Cyan, Magenta, and Yellow to create a richer, more consistent color coverage. A common formula for rich black is 40C, 30M and 30Y. Rich black is recommended for large areas of solid black.
RIP (Raster Image Processor): A device that renders PostScript code into the actual pattern of dots that will print on a given output device or printer.
Rosette: The pattern created when CMYK colors are printed at different angles. This method produces the best results when printing full color images.
Scoring: An indentation made along the fold line prior to folding. Scoring minimizes paper and ink cracking.
Spot Colors: Spot Colors, also called solid colors or Pantone colors, are premixed inks that are not attainable by combining CMYK inks.
Stock: Paper or other material to be printed.
Stochastic: Stochastic, also called FM screening (frequency modulated screening) contrasts with AM screening (produces rosettes at fixed angles). Stochastic screening produces fixed spot sizes usually measured in microns , 20 microns or as small as 10 microns), around the thickness of a human hair. Very high detail and wide dynamic range is possible with current direct-to-plate technology.
SWOP (Specifications for Web Offset Publications): SWOP, Inc. was established in 1974 to set standards for the printing industry so that quality and color issues could be made consistent throughout the print industry. SWOP states their mission to be “to continually raise the level of quality of publication printing by setting forth specifications and tolerances.”
TIFF (Tagged Image File Format): A file format for graphics that is particularly suited for representing scanned images and other large bitmaps. TIFF is platform-neutral, which aids in cross-platform compatibility.
Trapping: In printing, refers to printing over previously printed wet or dry ink. In prepress, refers to choking or spreading colors where they meet to prevent white gaps that could occur between colors in the printing process.
Uncoated Paper: Paper that has no coating applied. Most copier, business printing and letterhead papers are uncoated.
Varnish: A thin coating applied to printed matter for protection and to enhance and sharpen appearance.
Vector Information: Vector graphics describes the use of geometrical primitives such as points, lines, and curves to represent images in computer graphics.
Z-fold: A type of paper fold with the front and back flaps folded in the opposite direction to form a “Z.”