Printing Glossary

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Anti-aliasing: The process of averaging between pixels of different colors. This results is a smoother, more blended transition between the edge of two areas rather than a distinctly jagged appearance.

Bleed: Printing that goes to the edge of the sheet after trimming.

Brightness: The brilliance or reflectance of paper.

Burn: Exposing a printing plate to high intensity light or placing an image on a printing plate by light.

Color separations: The process of preparing artwork, photographs, transparencies, or computer generated art for printing by separating into the four primary printing colors.

CTP - Computer-to-Plate: A printing technology in which digital files are output directly to the printing to the plate. CTP eliminates the need for film and the chemicals associated with it.

Copy: All furnished material or disc used in the production of a printed product.

Crop: To cut off parts of a picture or image.

Crop marks: Printed lines showing where to trim a printed sheet.

Dot: An element of halftones. Using a loupe you will see that printed pictures are made many dots.

Dot gain or spread: A term used to explain the difference in size between the dot on film v paper.

DPI: Dots per inch used to express the resolution of a printer, that is, the number of individual dots of ink within a linear one-inch space.

Drop-out: Portions of artwork that do not print.

4-color-process: The process of combining four basic colors to create a printed color picture or colors composed from the basic four colors.

Gang: Getting the most out of a printing press by using the maximum sheet size to print multiple images or jobs on the same sheet. A way to save money.

Grain: The direction in which the paper fiber lie.

Grippers: The metal fingers on a printing press that hold the paper as it passes through the press.

Gutter: A blank space or margin between components on a printed piece or press sheet.

Halftone: Converting a continuous tone to dots for printing.

Image area: Portion of paper on which ink can appear.

Kerning: The narrowing of space between two letters so that they become closer and take up less space on the page.

Line Screen: Refers to the fineness of a halftone screen used to reporduce phots when printing. For example, most newspapers print with an 85-lines-per-inch screen.

Lines per inch: The number of rows of dots per inch in a halftone.

Offset: An erroneous variation of the word "setoff". Ink that is unintentionally transferred from a printed sheet to the back of the sheet above it as the pieces are stacked in a pile when printed.

Offset printing: The most commonly used printing method, where the printed material does not receive ink directly from a printing plate but from an intermediary blanket that receives the ink from the plate and then transfers it to the paper.

Overrun: Quantities of sheets printed over the requested number of copies.

Pica: Unit of measure in typesetting. One pica = 1/6 inch.

Plate: The sheet of metal that holds the ink and the image to be reproduced using a printing press.

PMS: The abbreviated name of the Pantone Color Matching System.

PostScript: The computer language most recognized by printing devices.

Preflight: The first step in prepress, preflighting ensures that all the files needed for a print job (fonts, images, etc.) are present and properly formatted.

Prepress: The steps taken to prepare digital files for final printing of a printing press. These may include preflight, color correction, imagesetting and platemaking.

Press Check: The press is stopped after a few impressions are made to ensure accuracy.

Process colors: Cyan (blue), magenta (process red), yellow (process yellow), black (process black).

PPI: Pages per inch or pixels per inch.

Register: To position print in the proper position in relation to the edge of the sheet and to other printing on the same sheet.

Register marks: Cross-hair lines or marks on film, plates, and paper that guide strippers, platemakers, pressmen, and bindery personnel in processing a print order from start to finish.

RGB: The color space of Red, Green and Blue. These are the primary colors of light, which computers use to display images on your screen. An RGB computer file must be translated into the CMYK (the primary colors of pigment) color space in order to be printed.

RIP: Raster Image Processor. This refers to a piece of hardware that converts Postscript data to a high-resolution raster image.

Saddle stitch: Binding a booklet or magazine with staples in the seam where it folds.

Skid: A pallet used for a pile of cut sheets.

Specifications: A precise description of a print order.

Spine: The binding edge of a book or publication.

Stet: A proof mark meaning let the original copy stand.

Stock: The material to be printed.

Tints: A shade of a single color or combined colors.

Trapping: The ability to print one ink over the other.

Trim marks: Similar to crop or register marks. These marks show where to trim the printed sheet.

Trim size: The final size of one printed image after the last trim is made.

Under-run: Production of fewer copies than ordered. See over run.

Up: A term used to describe how many similar pieces can be printed on a larger sheet; two up, four up, etc.

Vector: Graphics that are based upon mathmatical equations to represent the image. These graphics are resolution independent, that is, the can scale to any size without loss of quality. By contrast, a raster images is best described as a collection of pixels.

Web: A roll of printing paper.

Web press: The name of a type of presses that print from rolls of paper, usually cutting it into sheets after printing.