Printing Terms Glossary

Aliasing: Result when graphics, either constructed with lines (vector) or dots (bitmap), show jagged edges when magnified.

Artwork: A general term used to describe photographs, drawings, paintings, hand lettering, and the like prepared to illustrate printed matter.

ASCII: American Standard Code for Information Interchange. ASCII text can be recognized and understood by other computers and is useful when importing text from a word processing program into a typesetting system.

Author Alterations: Changes made to the document by the author after the first proof.

Autoflow: A mode of text placement where text flows continuously onto successive pages or columns. Depending on the program, additional pages are created automatically.

Bar code: Series of lines printed on a book which denote indexing and publisher information. Generating a bar code requires an ISBN number.

Baseline: Typography term -- the imaginary horizontal line upon which typeset characters rest.

Batch scan: Process of scanning several halftones at one time.

Binding: Fastening assembled sheets or signatures along an edge of a publication; e.g. saddle-stitch, perfect bound, case bound.

Bitmap: Representation of characters or graphics by individual pixels arranged in row and column order. Bitmapped font: A set of dot patterns that represent all the letters, characters and digits in a type font at a particular size.

Bitmapped graphics: Graphic images which are formed with sets of pixels (or dots) with a specific number of dots each. Also referred to as raster graphics, which are the opposite of vector images.

Blanket: A fabric coated with natural or synthetic rubber which is clamped around the blanket cylinder which transfers the ink from the press plate to the paper.

Blanket cylinder: The cylinder via which the inked litho plate transfers the image to the paper. The cylinder is covered with a rubber sheet which prevents wear to the litho plate coming into contact with the paper.

Bleed: A printed image that extends beyond the trim edge of the paper. To accommodate a bleed in book printing either the book is under-trimmed by 1/8" or a larger press sheet is used.

Blind emboss: A raised impression made without using ink or foil.

Blueline proof: A type of proof made by exposing the finished film on a proofing machine to light, which burns the image onto a special paper. It's then folded, trimmed and checked as a final checkpoint before printing.

Brightness: In color, the difference in range from white when compared to dark tones and colors, or contrast. In paper, the reflectance or brilliance of the paper.

Bullet: A large dot preceding text to add emphasis.

Calibration bars: On a negative, proof, or printed piece, a strip of tones used to check printing quality.

Caliper: The thickness of sheet of paper or board expressed in microns (millionths of a meter). Also the name of the tool used to make the measurement.

Camera ready art: Best results achieved from a laser printer with 600 dpi or better. Art that is ready to be shot on a camera or scanned into a computer for printing. Usually, if any additional alterations are made, corrected art is sent by the customer.

Caption: Also called a cutline. The line or lines of text that refer to information identifying a picture or illustration.

Case bound: A hardback book made with stiff outer covers. Cases are usually covered with cloth, vinyl or leather.

Cast Coated: Art paper with a exceptionally glossy coated finish usually on one side only.

Clip Art: Copyright free photos or drawings.

CMYK: Cyan, Magenta, Yellow and Black. The four colors used to create the illusion of a full color image in printing. Also referred to as four color process.

Coated paper: Printing papers which after making have had a surface coating with clay etc, to give a smoother, more even finish with greater opacity.

Collate: To gather separate sections or leaves of a book together in the correct order for binding.

Color correction: The process of adjusting an image to compensate for scanner deficiencies or for the characteristics of the output device.

Color proof: A representation of what the final printed composition will look like. The resolution and quality of different types of color can vary greatly.

Composite: In film terms, the negatives are stripped together and a proof provided.

Continuous tone: A photographic image which hasn't been screened for printing. An example would be a developed print in either black and white or color.

Contrast: Tonal gradation between highlights, mid tones and shadows in a graphic.

Crop: Mostly done in a computer environment, such as Photoshop, unneeded parts of a photo or graphic are removed to focus on the intended elements.

Cutline: Also called a caption. The line or lines of text that refer to information identifying a picture or illustration.

Densitometer: A device sensitive to the density of light transmitted or reflected by paper or film. Used to check the accuracy, quality, and consistency of output.

Density: A measure of the relative difference between a white area and a toned or black area.

Die: A hardened steel engraving stamp used to print an image.

Die cutting: The process of using sharp steel rules to cut special shapes into printed sheets.

Dithering: Simulating gray tones by altering the size, arrangement or shape of background dots.

Dot: The individual element of a halftone. Its size (or density) can be related to the density of the original used to produce the halftone dot. The dots are what the press sees when it prints a photo.

Dot gain: An increase in the size of halftone dots that may occur as a result of imperfections in any of the steps between screening an image and printing it onto paper. Common causes of mechanical dot gain are incorrect plate exposure, excessive tack or incorrect viscosity of printing ink, excessive ink film thickness, internal reflection of the ink or too much pressure between the blanket roller and the impression cylinder.

DPI: Dots Per Inch. A measurement of output device resolution and quality. Actually it measures the number of dots a printer or imagesetter can create per inch both horizontally and vertically.

Double page spread: Two facing pages where the textual material on the left hand side continues across to the right hand side.

Dummy: A preliminary layout before proofing.

Duotone: A two color halftone from a one color photograph.

Emulsion side: The side of the film coated with the silver halide emulsion which faces the lens during exposure. Most US printers use film that has emulsion down.

Encapsulated Postscript (EPS): EPS translates graphics and text into descriptions to a printer of how to draw them.

Film: A negative or positive, photographic or lithographic record made on a light sensitive material.

Flop: Turning a negative over to create a mirror image. Folio: A page number.

Foil stamping: The process of applying a thin film of colored foil to paper or cover material for decorative purposes.

Footer: Most often a publications name with a page number that appears on the bottoms of the pages of a publication.

Font: A graphical design applied to all numerals, symbols and characters in the alphabet. Also referred to as typeface.

FTP: File Transfer Protocol. Using an FTP site, you can upload and download information faster than any current method on the Internet. It's a format commonly used by printers to receive files from customers.

Four Color Process: The four basic colors of ink (CMYK--yellow, magenta, cyan, and black) which reproduce full-color photographs or art.

Galley proof: Text copy shown to a customer before it's formatted to a page.

Gathering: The operation of inserting the printed pages, sections or signatures of a book in the correct order for binding.

Graduate screen: A smooth transition between black and white, one color and another, or color and the lack of it.

Grayscale: A range of luminance values for evaluating shading through white to black. Also, a term used when referring to a black and white photograph.

GIF: Graphics Interchange Format. Commonly used for graphics on the Internet because the compressed size creates a smaller file. They are not suitable for printing because of that smaller size.

Grayscale: The range of shades of black in an image.

Gripper: The unprintable black edge on which the paper is gripped as it passes through the printing press.

Gutter: The two inner margins of facing pages in a publication.

Hairline: A .25-point rule.

Halftone: The production of continuous tone artwork, such as a photograph, through a screen that converts the image into dots of various sizes.

Hardback: A case bound book with a separate stiff board cover.

Hard copy: A printed rendition of what the final artwork should look like. Many printers require a hard copy to accompany a submitted disk so their pre-press operators will have something to follow.

Header: Text that appears at the top of every page.

Hickies: A dust particle sticking to the printing plate or blanket which appears on the printed sheet as a dark spot surrounded by an halo.

High resolution: Increasing the dots or pixels to create a better quality image. Also referred to as high res.

Highlight: The lightest or whitest part in a photograph represented in a halftone reproduction by the smallest dot or absence of dots in the highlight.

Imagesetter: An imaging device used to create film and sometimes plates. Capable of producing very high resolution output and a cornerstone in many pre-press environments.

Imposition: Laying out pages in a press form so that they will be in the correct order after the printed sheet is folded.

Insert: A printed piece usually independent of the original publication that will be merged in the finishing/binding stage.

ISBN: International Standard Book Number. The US agency, R.R. Bowker, assigns a publisher prefix number with a block of ISBN's. The ISBN is converted to a Bookland EAN number whereby a bar code can be generated and printed on the book. The bar code, then, acts as a standard cataloging system for the book for Internet, retail and library systems.

Italic: Type with sloping letters.

JPEG: Joint Photographic Experts Group. Another file extension used primarily on the Internet for graphics. As it's highly compressed, it's not ideal or recommended for printing.

Justify: The process by which a line of text is spaced between specified right and left hand margins.

Kerning: The amount of space between characters.

Keyline: An outline drawn or set on artwork showing the size and position of an illustration or halftone.

Knockout: A shape or object printed by eliminating (knocking out) all background colors. Contrast to overprinting.

Laminate: A thin transparent plastic coating applied to paper or board to provide protection and give it a glossy or matte finish.

Layout: The drawing or sketch of a proposed printed piece.

Leading: The distance between baselines of printed text, or the space between the lines.

Line screen: The resolution of a halftone expressed in lines per inch.

Lines per inch: A measurement of resolution.

Margins: The non printing areas of page.

Matchprint: A color proof created from the final film.

Mechanical binding: A method of binding which secures pre-trimmed leaves by the insertion of wire or plastic spirals through holes drilled in the binding edge.

Mock-up: (or layout dummy). The rough visual of a publication or design.

Moire pattern: The undesirable pattern which exists because of one screen angle overprinting another or several other screen angles.

Mylar: A polyester based film specifically suited for stripping film upon because of its mechanical strength.

Negative: Film containing an image in which values of the original are reversed to that the dark areas appear light and vice versa.

OPI: Open Prepress Interface. A viewing file which provides a link between the image placed in a page layout program and the high resolution separation needed by the imagesetter. It is automatically swapped out when the file is prepped for output.

Overprinting: Printing over an area that has already been printed. Often used to enhance a particular color.

Pagination: Typesetting term which copy, page numbers and other elements of a printed page are assembled. Pantone colors: Also referred to as PMS colors. A series of over 1200 colors which have become standard inks in the printing business.

PDF file: Portable Document Format, is a file format created by Adobe Systems, Inc. PDF uses the PostScript printer description language and is highly portable across computer platforms. PDF documents have a .pdf file extension.

PICT: A picture file format developed by Apple. It stores the image with a lower resolution.

Pixel: When an image is defined by many tiny dots, those dots are pixels.

Positive: A film or pint containing an image in which the light and dark values are the same as the original. The reverse would be negative.

Postscript: A page definition language commonly used in the printing industry. Postscript files are necessary for creating PDF files. Postscript is unique because it is platform independent and doesn't rely on a specific program.

PPD file: Postscript Printer Description file. A file that contains information on screen angle, resolution, page size and device-specific information for a file to be printed on a postscript device.

Pre-Press: A department within a printing company where film, plates and proofs are assembled.

Proof: A representation created either with finished film or from a laser printer to be approved before committing ink to paper.

Raster image: An image displayed as a series of lines of dots or video "blips."

Reader's spread: Two sequentially numbered pages of a document placed side by side.

Register: The fitting of two or more images on the same exact spot either on paper or mylar thereby insuring exact alignment with each other.

Resolution: Measure of image output capability usually expressed in dpi (dots per inch). Measure of halftone quality usually expressed in lpi (lines per inch).

RGB: Red, green, blue. The additive primary colors used for computer monitor displays; also a color model. Cannot be used for printing. All RGB files must be changed to CMYK to be printed.

Right reading: Normal left to right image reproduction. Usually referred to as right reading, emulsion down in terms of film.

RIP: Raster Image Processor. The RIP converts data which has been stored in a computer into a series of lines of tiny dots which are output on film or paper.

Sans serif: Typefaces that have the same weight and thickness throughout.

Scan: To convert photos or graphics into files that can be placed into a page layout program or manipulated by a graphics program.

Screen angles: it is necessary to rotate the angles of the screens in order to create a rosette pattern. Using a horizontal line as a base plane, the first angle would be found at 45 degree angle from the base, 75 degrees would be the next, 90 degrees and finally 105 degrees.

Screen font: A raster font designed to duplicate a printer font on the screen. When submitting Type 1 fonts it's vital to include both the screen and printer versions of the fonts.

Serif: Short cross lines appearing at the ends of the main strokes of characters in a typeface.

Signature: A printed sheet containing several pages in such an order that when folded comes out in sequential order.

Tack: The property of cohesion between particles in printing inks.

TIFF: Tag Image File Format. The file format of choice for photographs.

Trapping: The ability to print wet ink film over previously printed ink. Improper trapping will cause color changes.

Trim marks: guides that show where a document will be cut.

True type: A font format where all the elements are contained in one file.

Varnishing: A finishing process whereby a transparent coating is applied over the printed sheet to produce a glossy finish.

Vector: Images defined by sets of straight lines, defined by the locations of the end points. At larger magnifications, curves may appear jagged.