Pre-press Terminology

November 27, 2006

Pre-press Terminology

Half-tone (2040-41) - 1. the reprographic technique, developed in the 1880s, of reproducing a continuous tone image on a printing press by breaking it up into a pattern of equally spaced dots of varying size. This determines tones or shades - the larger the dots, the darker the shade. 2. Any image reproduced by the halftone process.

Half-tone screen (2045) - conventionally, a sheet of glass or film cross-hatched with opaque lines, used to convert a continuous tone image into halftone dots so it can be printed. Computer applications generate a halftone screen digitally without ht he need for a physical halftone screen, by generating each halftone dot as an individual "cell," itself made up of "printer" dots. Also called cross line screen or contact screen.

Continuous tone (2105) - (CT) - an image that contains infinite continuous shades between the lightest and darkest tones, as distinct from a "line" illustration that has only one shade. Usually used to describe an image before it is either broken up by the dots of a halftone screen for printing or "dithered" into a pattern of colors for viewing on low-resolution monitors. Also called contone.

Color separation (2104) - the process of dividing a multicolored image into the four individual process colors - cyan, magenta, yellow, and black (by using red, green, and blue filters) - so the image can be reproduced on a printing press. Conventionally, this is done using the filters in a "process" camera, but color separation are now prepared digitally on a scanner or on a computer.

Moiré (2061) - an unintended pattern that occurs in halftone reproduction when two or more colors are printed and the dot screens are positioned at the wrong angles. The correct angles at which screens should be positioned usually depend upon the number of colors being printed, but the normal angels for four-color process printing, and thus the default setting in many computer applications, are: cyan 105; magenta 75; yellow 90; black 45. A moiré pattern can also be caused by scanning or rescreening an image to which halftone screen has already been applied

Proof (3749-52) - a prototype of a job, taken at various stages from laser printers, imagesetteters, inked plates, stones, screens, block, type, or so on, to check the progress and accuracy of the work. Also called a pull.

Highlight (4126) - the lightest tone of an image, the opposite of shadow.

Midtone (3532) - the range of tonal values in an image, anywhere between the darkest and lightest, usually referring to those approximately halfway.

Shadows (3551) - the areas of an image that are darkest or densest.

Stochastic screening (2083) - a method of reproducing an image by applying a "screen" of scattered microdots, each one sometimes no larger than a machine dot, and by which 256 grays (or more) can be rendered without varying the dot size. It differs from conventional halftoning in that the dots are not distributed in a grid pattern, but placed in accordance with an algorithm that statistically evaluates their distribution within a fixed set of parameters. Stochastic screening offers many advantages over conventional halftone screening because as well as giving the impression of a continuous tone reproduction (it is sometimes described as "screenless" printing), it eliminates "moiré" patterns, allows a wider range of colors, and does not cause a shift in colors if there is misregister during printing. Also called FM screening.

Screen angle (2067) - the angel at which halftone screens of images printing in two or more colors are positioned to minimize undesirable dot patterns (moiré) when printed. The angle at which screens should be positioned depends upon the number of colors being printed, but the normal angles for four-color process printing are: cyan 105; magenta 75, yellow 90, black 45.

Screen frequency (2069) - the number of line rulings per inch (lpi) on a halftone screen.

Screen ruling (2073) - in halftone screens, the number of ruled lines per inch or centimeter. The greater the number, the finer the resolution. The range in common use varies from about 85lpi for halftones printed on newsprint, to 150lip or more for those printed on art papers. The default setting on laser printers is usually about 80lpi. Although the abbreviated form, lpi, is sometimes use, it is more usual to express a "150lpi" - screen, for example, as a "150-line" screen.

Screening (2076) - turning a continuous-tone image into a pattern of dots of various sizes by photographing it through a halftone screen placed in front of the photographic emulsion.

FM screening (2036) - frequency modulated screening: a method of screening an image for reproduction that uses a random pattern of dots to reproduce a continuous tone image. Also known as stochastic screening.

AM screening (1994) - amplitude modulated screening: an alternative name for conventional halftone screen - those screens that break up a continuous tone image into a regular pattern of different sized dots.

Dot gain (2016) - the tendency, during the reproduction chain from original to printed image, of halftone dots to grow in size, either photographically in prepress stages, or in ink during printing. This often leads to inaccurate results, but, if the dot gain characteristics of a particular printing press are known, compensation can be made during reproduction. A dot gain scale - part of a color control bar - is usually included on proofs to check this occurrence, and is specified as a percentage of the size of the dot. Dot gain is the opposite of dot loss.

Calibration (3492) - the process of adjusting a machine or piece of hardware to conform to a known scale or standard so it performs more accurately. In graphic reproduction it is important that the various devices and materials used in the production chain, such as scanners, monitors, imagesetters and printing presses, conform to a consistent set of measures to achieve true fidelity, particularly where color is concerned. Calibration of reproduction and display devices is generally carried out with a "densitometer."

Calibration bar (2102) - the color device printed on the edge of color proofs or in the trim area of press sheets that enables the repro house and printer to check - by eye or with instruments - the fidelity of color separations and the accuracy of printing. The color bar helps to monitor such things as ink density paper stability. Dot gain, trapping, and so on. Also called a codet.

Registration (2696) - the correct positioning of color plates when printed one on top of another, or of the pages on one side of a sheet relative to the other (called "backing up"). When a color or page is incorrectly positioned, it said to be "out-of-register" or "misregistered." As distinct from "fit," which applies to the correct positioning of individual items on a sheet.

Tack (2834) - the degree of "stickiness" of printing ink, in other words, the degree to which it will divide ("split") between two surfaces so some prints on the substrate (without damaging it) while some remains on the printing surface.

Registration marks (2132) - the marks used on artwork, film, and printing plates that are superimposed during printing to make sure the work is in register. Many graphics applications automatically generate register marks outside the page area. Also called crossmarks or t-marks.

Coated paper (2486) - a general term describing papers that have had a mineral coating applied to the surface - after the body paper was made, such as art chromo, and enamel papers. Coated paper is also known as surface paper.

Dpi (1031) - dots per inch - a unit of measurement used to represent the resolution of devices such as printers and imagesetters, and also, erroneously, monitors and images, whose resolution should more properly be expressed in pixels per inch (ppi). The closer the dots or pixels (the more there are to each inch), the better the quality. Typical resolutions are 72ppi for monitor, 300 dpi for laserwriter, and 2450dpi (or more) for an imagesetter.

Dot (1030) - a term that can mean one of three things: halftone dot (the basic element of a halftone image), machine dot (the dots produced by a laser printer or image setter), or scan dot (strictly speaking, pixels, which comprise a scanned bitmapped image). Each is differentiated by being expressed in lpi (lines per inch) for a halftone dot, dpi (dots per inch) for a machine dot, and ppi (pixels per inch) for a scan dot - although the latter is sometimes being expressed erroneously - in dpi. Thus, because the term dot is used to describe both halftone and machine dots, scan dots should always be referred to as pixels.

Spot color (2723) - any color used for printing that has been "custom mixed" for the job, as opposed to one of the four standard process colors.

Varnish (3358-59) - a liquid that dries with a hard surface and that is generally insoluble in water. It is used in the manufacture of printing inks, in some dying agents, and as a surface protector.

Solid (2832) - an area printed with 10 percent of color.

Screen tint (2046) - a printed area of even tone, achieved by uniform halftone dots. Tints are specified in percentages of the solid color. Also called a screen tint.

Pantone (3536) - The proprietary trademark for Pantone Inc.'s system of color standards, control and quality requirements, in which each color bears a description of its formation (in percentages) for subsequent printing. The PANTONE MATCHING SYSTEM is used throughout the world so colors specified by any designer can be matched exactly by any printer.

Make-ready (2645) - the process of preparing a printing press before a new run, to establish register, ink density, consistent impression, and so on

Separations (2161) - the set of four films for each of the four process colors - cyan, magenta, yellow, and black - generated as a result of the color separation process.

Aqueous -

UV coating -

Lacquer (3307) - a solution that provides a glossy finish and a protective coating.

Knockout (2051) - an area of background color that has been masked "knocked out" by a foreground object, and therefore does not print. The opposite of "overprint."

Knocked-out type (1848) - type that is reversed out of its background to read, for example, as white on a color.

Cross-overs (3920) - an image or tint that extends across the gutter onto both pages of a double-page spread. Also called break across, or reader's spread.

Matte (2299) - a paper with a flat, slightly dull surface

Gloss (2284) - the amount of light, reflected by the surface of paper ("reflectance"). Machine-finishing under pressure through rollers can give a slight gloss.

Direct to plate (2590) - (CTP - computer-to-plate) the process of making printing plates directly from digital data, without the need for film.

Ink drawdown (2786) - the technique of assessing the color of a printing ink by thinly spreading a small amount on a sample of the paper on which it is finally to be printed.

Solid (2832) - an area printed with 100 percent of a color.

Dot gain (2016) - the tendency, during the reproduction chain from original to printed image, of halftone dots to grow in size, either photographically in prepress stages, or in ink during printing. This often leads to inaccurate results, but, if the dot gain characteristics of a particular printing press are known, compensation can be made during reproduction. A dot gain scale - part of a color control bar - is usually included on proofs to check this occurrence, and is specified as a percentage of the size of the dot. Dot gain is the opposite of dot loss.

Finish (2275) - the surface of a paper, usually one that is coated or embossed.

Dot shape (2020) - the shape of the dot in a halftone screen. Although traditional halftones use round dots (which actually look square in the midtones), some applications or output devices allow you to choose between round, square, linear (not actually dots, but lines) , and elliptical dot shapes. Elliptical dots are less prone to dot gain than round dots, while linear screens are used for visual effects rather than for any particular benefit to the reproduction of the image.

Scatter proof (2224) - a single-color proof containing unrelated images placed randomly and without reference to their final position. The process is used to cut costs when large numbers of pictures are needed, for example, in a magazine or illustrated book. Also called a random proof.

Color separation (2104) - the process of dividing a multicolored image into the four individual process colors - cyan, magenta, yellow, and black (by using red, green, and blue filters) - so the image can be reproduced on a printing press. Conventionally, this was done using the filters in a "process" camera, but color separations are now prepared digitally on a scanner or on a computer.

Screen angle (2067) - the angle at which halftone screens of images printing in two or more colors are positioned to minimize undesirable dot patterns (moiré) when printed. The angle at which screens should be positioned depends upon the number of colors being printed, but the normal angels for four-color process printing are: cyan 105, magenta 75; yellow 90; black 45.

Ink coverage (2803) - the measure of the area that a given amount of printing ink is capable of covering satisfactorily.

Preflight (0767) - the process of checking and collating front, graphic, picture, and all other items associated with an electronic file that are required for output to imagesetter.

Duotone (2029) - a monochromatic image combining two halftones with different tonal ranges made from the same original, so that, when printed in different tones of the same color (usually black, when it is sometimes described as a "double-black duotone"), a wider tonal range is reproduced than is possible with a single color. Special effects can be achieved by using the same technique printed with different colored inks. The term I sometimes used erroneously to describe a "duplex halftone," or "FALSE DUOTONE" (a duplicate halftone printed in two colors)

Screen tint (2046) - a printed area of even tone, achieved by uniform halftone dots. Tints are specified in percentages of the solid color. Also called a screen halftone tint.

Spot color (2723) - any color used for printing that has been "custom mixed" for the job, as opposed to one of the four standard process colors.

Thermography (2988) - a printing process that emulates die stamping (but without embossing), in which sheets are printed with a sticky ink or varnish and then dusted with a fine, pigmented powder that forms a raised surface when fused to the paper by heat.

Trapping (2085) - the slight overlap of two colors to eliminate gaps that may occur between them due to the normal fluctuations of registration during printing. Also refers to printing an ink color before the previous one has dried - also called wet tripping.

Choke (1998) - one of the "trapping" techniques (along with "spread)) used in print preparation for making sure two abutting areas of ink print without gaps. A choke traps a surrounding light background to a dark, inner foreground object by expanding the edge of the inner object so the two colors overlap. Because the darker of the two adjacent colors defines the visible edge of the object, it is always preferable to extend the lighter color into the darker. Traditionally, spread and chocks were achieved by slightly overexposing the film so the image areas expanded, and the piece of film used for the choke was alternatively termed a "skinny." Nowadays, software applications provide automatic trapping features.

Spread (2080) - one of the "trapping" techniques (along with "choke) used in print preparation for making sure two abutting areas of ink print without gaps. A choke traps a surrounding light background to a dark, inner foreground object by expanding the edge of the inner object so the two colors overlap. Because the darker of the two adjacent colors defines the visible edge of the object, it is always preferable to extend the lighter color into the darker. Traditionally, spread and chocks were achieved by slightly overexposing the film so the image areas expanded, and the piece of film used for the choke was alternatively termed a "skinny." Nowadays, software applications provide automatic trapping features.

Creep (3259) - the displacement of the leaves in each signature of a book due to the effect of folding. Creep increases with paper thickness. Also known as thrust, shingling, and pushout.

Setoff (3066) - the accidental transfer of wet ink on a freshly printed sheet to the back of the next on the delivery pile.

Paste-up (4055) - the layout of a design, including all elements such as text and illustrations. A paste-up will either be "rough" for layout and markup purposes or "camera-ready" (also known as mechanical), which will be used to make film for reproduction.

Stripping (2148) - the gathering together and arrangement of all the separate components used to make final film, or "flats," used for platemaking. Also called stripping, film assembly, film makeup, or image assembly.

Service bureau (2225) - a company that provides digital image services, such as color scanning and high-resolution imagesetting.

Wood cut (3033) - a traditional method of printing using images and type carved - out of wood - in relief.

Relief block (3025) - a letterpress line or halftone block

Relief plate (3026) - a printing plate with a raised printing surface

hot metal (1802) - the general term given to type set on a compositing machine, now largely obsolete, which casts type from molten metal either as single characters (as per Monotype) or as complete lines (as per linotype.)

Manuscript (3737) - an original text submitted for publication

Illuminated (4127) - a term describing the technique of embellishing letters, pages, manuscripts, and so on, by using gold, silver, and colors; common in medieval times

Letterpress (3015) - the original relief printing process in which the surface of a raised, or relief, image or piece of type is inked and then pressed onto paper or some other surface.

Compositor/typesetter (1795) - the person who sets type - originally individual pieces of metal set by hand, but now by any method. An increasingly rare breed since the computer has all but eliminated this trade. Traditionally called a "typographer" in the US, which, now that the designer has total control over typography, is probably a more appropriate description. In the days of metal type, the compositor would also make up and impose pages. Also called a typographer or typesetter, although the latter can also mean the machine upon which type is set.

Casting (1788) - the traditional method of generating type characters by using machines that, fitted with a mold or "matrice" (mat), would cast the type characters from hot molten metal. Type would either be cast as individual characters using a "monotype" machine, or as complete lines ("slugs") using a "linotype" machine.

Intaglio (2872) - a printing process in which the image to be printed is recessed below the surface of the plate, such as in commercial gravure printing or fine-art etching.

Lithography (2937) - a "planographic" printing process invented in 1798 by Aloys Senefelder, a German, in which an image is produced from a damped, flat surface, using greasy ink; based on the principle of the mutual repulsion of oil and water

Silkscreen printing (3049) - a traditional method of "serigraphic" printing in which ink is forced through a stencil fixed to a screen made of silk. Today, however, the screen is made of synthetic material and the process is generally called "screen printing."

Tip(ped) in/on (3072) - a page or image inserted separately into a book and secured by pasting one edge.

Emboss(ing) (3444) - relief printing or stamping in which dies are used to impress a design into the surface of paper, cloth, or leather so the letters or images are raised above the surface. Also known as waffling

Flatbed (2979-81) - a type of printing press on which the paper sheets sits on a horizontal surface; used for proofing

Upper case (1990) - the capital letters of a type font, the term deriving from the compositor's "case" - trays of type that were generally used in pairs, upper for capital letters and lower for small letter

Lower case (1968) - the small letters in a font, as distinct from capitals - upper case. Also called minuscule.

Etching (2177+2865) - to dissolve away an area of printing plate to produce either a relief image or intaglio image (depending on the printing method) or, on film, to reduce the size of halftone dots. The term is also used to describe the process of desensitizing the nonimage areas, which are protected by a "ground," of a litho plate to make them receptive to water instead of ink.

Engraving (2863-64) - a block or plate made from wood or metal into which a design or lettering has been cut, engraved, or etched; a print taken from an engraved plate or block

Collotype (2913) - a "planographic," photomechanical printing process that uses a gelatin-coated plate onto which the image is photographically exposed without using a halftone screen, thus achieving continuous tones. Colletypes are typically used for short-run fine-art edition prints. Also known as photogelatin printing.

Continuous tone (2105) - an image that contains infinite continuous shades between the lithest and darkest tones, as distinct from a "line" illustration that has only one shade. Usually used to describe an image before it is either broken up by the dots of a halftone screen for printing or "dithered" into a pattern of colors for viewing on low-resolution monitors. Also called contone.

Stencil (3051) - in screen printing, the material used to prevent ink transferring through the screen to the nonimage areas of the paper.

Squeegee (3050) - a blade or paddle device, usually made of rubber or plastic, that forces ink through the open areas of the mesh and stencil in the screen-printing process.

Photo typesetting (2179) - at one time, a term describing typesetting output onto photographic paper or film form a film matrix, when it was also called "filmsetting" or "photocomposition," but now extended to include, by virtue of the output medium being photographically based, computer typesetting produced on an imagesetter.

Mechanical (4013) - CRC - material such as artwork, prepared and ready for photographic conversion to film in preparation for printing. Also called camera-ready, composite art, or paste-up.

Graphic arts (3688) - the general term encompassing the entire craft of reproduction by means of any of the many printing processes. As distinct from "graphic design" - providing a graphic solution to a specific problem and the implementation of that solution by whatever means.

Graphic design (3689) - strictly speaking - and in its literal sense - graphic design is the arrangement and combination of shapes and forms based on 2D processes, such as typography, photography, illustration, video motion picture, multimedia, and various print methods, but not necessarily excluding 3D design, because graphic design is utilized in many 3D contexts, such as package design, product design, exhibition, and architecture. In its less literal sense, graphic design embodies the profession of visual communication in as much as it forms an integral part of any marketing concept or strategy. Traditionally called commercial art, there are many alternative names, such as graphic arts (although this implies more technical connotations), graphic communication, and so on, but it should not be confused with "desktop publishing."

Galley (3724) - a proof of typeset text before it is integrated into a page design, deriving from the days when metal type was proofed from a long, shallow, three-sided metal tray called a "galley." Also called a slip proof, referring to the broad strip of paper on which a galley proof is printed.

Markup (4046) - a set of instructions and specifications for any material prepared for typesetting, reproduction or printing.

Dummy (4023) - a mock-up of a design, such as a pack or illustrated book, showing the position of headings, text, captions, illustrations, and other details.

Comprehensive (4018) - a preliminary rendition of a design, simulating the printed item, but to show intent rather than final detail. A typical comp will consist of illustrations, photographs, and typeset text, - not necessarily those that will actually be used, but that are close enough to convey the concept. Also variously called a mockup-, presentation visual, finished rough, or dummy.

Stripping (2141) - inserting a typeset correction into film or camera ready art

Platemaking (2675) - the process of making an image on a printing plate by whatever means, but usually photo mechanically transferring it from film

Offset (2943) - a printing technique in which the ink is transferred from the printing plate to a "blanket" cylinder and then to the paper or material on which it is to be printed.

Offset litho(graphy) (2946) - a lithographic printing technique, developed in the United States in the early 1900s, in which the image is printed indirectly by "offsetting" it onto a rubber-covered cylinder, called a "blanket" cylinder, from which the image is printed. It is one of the most widely used commercial printing processes.

Blanket cylinder (2906) - in offset litho printing, the cylinder to which the blanket is attached. The blanket transfers the inked image from plate to paper.

Sheet-fed press (2714) - a printing press into which single sheets are fed

Impression cylinder (2628) - the cylinder on a rotary press that holds the paper as it is brought into contact with the type, plates, offset roller, or blanket cylinder. Also called a back cylinder.

Web offset (2962) - a rotary printing press that uses a continuous reel-fed paper "web" where the impression (image) from the plate is offset onto a blanket (usually rubber) before being printed onto the paper. There are three main systems: "blanket to blanket," in which two plates and two blanket cylinders on each unit print the web; three-cylinder systems, in which plate blanket and impression cylinders print one side of the paper only; and satellite or planetary systems, in which two, three, or four plate and blanket cylinders are arranged around a common impression cylinder, printing one side of the web in as many colors as there are plate cylinders.

Blanket-to blanket press (2909) - in offset printing, a configuration in which a continuous web of paper is fed between two blanket cylinders, printing both sides at once. Also called a perfecting press.

Inking mechanism (2630) - the arrangement of ducts and rollers on a printing press that control automatic distribution and delivery of ink to substrate. Also called inking system.

Fountain (2930) - the reservoir containing either ink or dampening solution on a litho press.

Gripper(s) (2617-19) - the edge of a sheet of paper that is held by the grippers of a printing press. Also known as the feeding edge. The opposite of the leaf edge.

Converter (2915) - a type of offset litho printing press that can be converted to print either two colors on one side of a sheet or a single color on both sides in one pass.

Gravure (2868) - an "intaglio" printing process in which the image areas to be printed are recessed below the nonprinting surface of the printing plate. These recesses (cells) are filled with a liquid ink - the surprise removed from the nonprinting pares by the "doctor blade" - and the paper draws the ink from the cells.

Photogravure (2881) - the photomechanical preparation of plates for use in intaglio printing process.

Doctor blade (2598) - a long, thin, flexible steel blade used variously to remove or apply ink or coating before or after printing. For example, a doctor blade is used in gravure printing to wipe excess ink from the surface of the printing cylinder.

Flexo(graphy) (2982) - a relief printing process that uses flexible rubber or plastic plates. Used mainly for printing onto various kinds of packing, and sometimes newspapers where it may be referred to as "anilox" printing.

Aliasing (0726) - the jagged appearance of bitmapped images or fonts occurring either when the resolution is insufficient or when the images have been enlarged. This is caused by the square pixels making up the image becoming visible to the eye. Sometimes called jaggies, staircasing, or stairstepping.

Anti-aliasing (0727) - a technique of optically eliminating the jagged effect of bitmapped images reproduced on low-resolution devices such as monitors. This is achieved by blending the color at the edges of the object with its background by averaging the density of the range of pixels involved. Antialiasing is also sometimes employed to filter texture maps, such as those used in 3D applications, to prevent moiré patterns.

Typeface (1780) - the term (based on "face" - the printing surface of a metal type character) describing a type design of any size, including weight variations on that design such as light and bold, but excluding all other related designs such as italic and condensed. As distinct from a "type family." Which includes all related designs, and a "font," which is one design of a single size, weight, and style. Thus Baskerville is a type family, whereas Baskerville bold is a typeface ad 9pt Baskerville bold italic is a font.

Font/fount (1749) - originating from the world found - as in typefoundry - a font is traditionally a complete set of type characters of the same design, style, and size. For example, 10 point Baskerville old style bold italic is a font. On a computer, however, although each font is a unique design and style, any size can be rendered from a single font file. There are two formats: postscript type 1, which comes in two parts - bitmapped screen fonts and outline printer fonts; and truetype, in which each font is a single file.

Font family (1748) - the complete set of characters of a typeface design in all its sizes and styles. A typical font family contains four individual fonts: roman, italic, bold, and bold italic. As distinct from a typeface or font. Also known as type family.

Point (1708) - the basic unit of Anglo-American type measurement. In the past, no two printers could agree on a standard system of type measurement; therefore, type cast in one foundry could not be mixed with that cast I another. However, in the mid 18th century, the French typographer Pierre Simon Fournier introduced a standard unit that he called a point. This was further developed by Francoise-Ambroise Didot into a European standard (Didot point), although this was not adopted by either Britain or the US. The Anglo-American system divides one inch into 72 parts, each one a point (mathematically, one point should equal 0.013889 inch but, in fact, it equals 0.013837 inch, with the result that 72 points equal only 0.996264 inch. The European Didot point equals 0.0148 inch and 12 of the Anglo-American point and the Didot point, and neither of them relate to metric measurement. The introduction of the computer as a design tool has established a new international standard of measurement based on Anglo-American system. However, on the computer, one point measures 0.013889 inch, and 72 points equals exactly one inch - no coincidence, then, that computer monitors have a standard resolution of 72dpi.

Pica (1706) - a typographer's and printer's unit of linear measurement, equivalent to 12 points. One inch comprises .022 picas or 72.27 points. Computer applications, however, use the postscript value of exactly six picas, or 72 points, to the inch.

Dpi (1031) - a unit of measurement used to represent the resolution of devices such as printers and imagesetters, and also, erroneously, monitors and images, whose resolution should more properly be expressed in pixels per inch (ppi). The closer the dots or pixels (the more there are to each inch), the better the quality. Typical resolutions are 72ppi for a monitor, 300dpi for a laserwriter, and 2450dpi (or more) for an imagesetter.

Measure (1703) - the width of a justified typeset line or column of text, traditionally measured in picas, points. Didots, or Cicero's, but now commonly in inches and millimeters as well. Also referred to as a line length.

Em (1686) - traditionally, the width occupied by a capital M that, usually being a square, gave rise to a linear measurement equal to the point size of the type being set; thus, a 9point em is 9 points wide. A 12 point em is generally called a pica, or pica em, and measures 4.22mm (0.166 inch). Half an em is called an en.

En (1690) - half an em.

Reverse out/reverse type (4058) - to reverse the tones of an image or type so it appears white (or another color) in a black or colored background. Also called dropout, save out, or knock-out.

Knockout (1848) - type that is reversed out of its background to read, for example, as white on a color. Also called versed out or knocked out type.

Surprint (2659) - to make a second printing or "pass" on a previously printed sheet. Also called overprinting.

Overrpint (2660) -to print two or more colors so they overlap, either to produce more colors or to avoid registration problems. The opposite of "knockout."

Loupe (3614) - a lens used to inspect the quality of printing proofs, film, photographic transparencies, and so on. Some magnifiers incorporate additional features, such as adjustable focus, built-in measuring scales, and its own light source. Also called a magnifier/magnifying glass, or linen tester (after the folding device used in the textile industries for counting treads in linen.)

Undercolor removal (2087) - UCR - a reproduction technique of removing color from the shadow areas of scanned color separations, either to reduce the amount of ink or because the colors cancel each other out. For example, if there is enough black and cyan to cover, the magenta and yellow dots are removed. UCR can also reduce trapping problems in printing.

Gray component replacement (2039) - GCR - a color separation technique in which black ink is used instead of overlapping combinations of cyan, magenta, and yellow to create gray shades. This technique avoids color variations and trapping problems during printing.

Transparencies (1417) - a photographic image on transparent film generated, after processing, as a positive image. Color transparencies are ideal as originals for color separations for process color printing, as they provide a greater variety of colors than reflective prints. Color transparency film is supplied for a variety of camera formats, typically 35mm, 2 ¼ inch square, and 4x5 inch. Color transparencies are also known variously as trannies, color trannies, slides (which generally refers to 35mm only), and color reversal film.

FPO (4030) - for position only - a term used to indicate that items positioned on a layout are of inappropriate quality for reproduction and are displayed only as a guide for positioning in lieu of the properly prepared version.

TIFF (0494) - tagged image file format - a popular graphics file format originally developed by Aldus (now part of Adobe) and Microsoft, used for scanned, high-resolution bitmapped mages, and for color separations. The TIFF format can be used for black-and-white, grayscale, and color images that have been generated on different computer platforms.

EPS (0375) - encapsulated postscript - a standard graphics file format used primarily for storing "object-oriented." Or "vector," graphics files (a vector is a tiny database giving information about both magnitude and direction of a line or shape) generated by "drawing" applications such as adobe Illustrator and Macromedia FreeHand. An EPS file usually has two parts: one containing the Postscript code, which tells the printer how to print the image; the other an on-screen preview, which can be n PICT, TIFF, or JPEG formats. Although used mainly for storing vector-based graphics, the EPS format is also widely used to store bitmapped images, particularly those used for desktop color separation (DCS), and these EPS files are encoded as either ASCII - a text-based description of an image - or binary, which uses numbers rather than text to store data. Bitmapped eps files to be printed on the Mac OS are usually saved with binary encoding, although not all printing software supports binary EPS files.

JPG (0761) - joint photographic experts group - an ISO group that defines compression standards for bitmapped color images. The abbreviated form, pronounced "jay-peg" gives its name to a "lossy" (meaning some data may be lost) compressed file format in which the degree of compression from high compression/low-quality to low compression/high-quality can be defined by the user. This makes the format doubly suitable for images that are to be used either for print reproduction or for transmitting across networks such as the internet - for viewing in web browsers.

GIF (1261) - graphic interchange format - a bitmapped graphics format oringally devised by Compuserve, an Internet service provider (now part of AOL), and sometimes (although rarely) referred to as Compuserve GIF. There are two specifications: GIF87a and, more recently, GIF80a, the latter providing additional features such as transparent backgrounds. The GIF format uses a lossless compression technique and thus does not squeeze files as much has JPEG format, which is lossy (some data is discarded). For use in web browsers, JPEG is the format of choice for tone images such as photographic, whereas GIF is more suitable for line images and other graphics, such as text.

PNG (1293) - portable network graphics - a file format for images used on the web that provides 10=-30 percent lossless compression, and supports variable transparency through "alpha channels," cross platform control of image brightness and interlacing.

Line art (2121) - artwork or camera-ready copy consisting only of black on white, with no intermediate tones and thus not requiring halftone reproduction (although shaded tones can be applied with "mechanical tints"). Also called line copy, line work, or line originals.

Halftone (2044) - the smallest basic element of a halftone. It may be round, square, elliptical, or any other shape. The frequency of halftone dots is measured in lines per inch (lpi) or per centimeter (lpc).

Halftone screen (2045) - conventionally, a sheet of glass or film cross-hatched with opaque lines, used to convert a continuous tone image into halftone dots so it can be printed. Computer applications generate a halftone screen digitally without the need for a physical halftone screen, by generating each halftone dot as an individual "cell," itself made up of "printer" dots. Also called a crossline screen or contact screen.

Dot pattern (2018) - the pattern created by halftone dots after all colors are printed. A halftone image printed in register and with the correct halftone screen angles will produce a rosette pattern, whereas incorrectly angled halftone screens will produce a pattern known as "moiré."

Screen angle (2067) - the angle at which halftone screens of images printing in two ore more colors are positioned to minimize undesirable dot patterns (moiré) when printed. The angle at which screens should be positioned depends upon the number of colors being printed, but the normal angles for four-color process printing are: cyan 105, magenta 5; yellow 90, black 45.

Lines per inch (2053) - the measurement of the resolution, or coarseness, of a halftone, being the number of rows of dots to each inch.

Duotone (2029) - a monochormoatic image combining two halftones with different tonal ranges made from the same original, so that, when printed in different tones of the same color (usually black, when it is sometimes describie

Tritone (3561) - a halftone image that is printed using three colors. Typically, a black-and-white image is enhanced by the addition of two colors, such as process yellow and magenta that, when added to black, will produce a sepia-colored image.

Grayscale (1505+0756) - a tonal scale printed in steps from white to black and used for controlling the quality of both color and black-and-white photographic processing, and also for assessing quality in a halftone print. A grayscale (also called a step wedge, half-tone step scale, or step tablet) is sometimes printed on the edge of a sheet; the rendering of an image in a range of grays from white to black. In a digital image and on a monitor, this usually means that an image is rendered with eight "bits' assigned to each pixel, giving a maximum of 256 levels of gray. Monochrome monitors (rarely used nowadays) can only display black pixels, in which case grays are achieved by varying the number and positioning of black pixels using a technique called dithering.

WYSIWYG (1019) - wizzywig - an acronym for "what you see is what you get." The display of a document on screen exactly as it appears when printed. All major computer operating systems now offer WYSISYG displays.

Mask (3530) - any material used to protect - from light, paint, or whatever - all or part of an image or page in photomechanical reproduction, photography, illustration, or layout. Many computer applications provide a masking feature that enables you to apply a mask to all or selected parts of an image. Such masks are stored in an "alpha channel" and simulate the physical material used in plate making, which is used to shield parts of a plate from light.

Alpha channel (0513) - a place where information regarding the transparency of a pixel is kept, in image files this is a separate channel - additional to the three rgb or four CMYK channels - where "masks" are stored, simulating the physical material used in plate making to shield parts of a plate from light.

Clipping path (0347) - a Bezier outline that defines which areas of an image should be considered transparent or "clipped." This lets you isolate the foreground object and is particularly useful when images are to be laced on top of a tint background in a page layout, for example. Clipping paths are generally created in an image-editing application such as Adobe Photoshop and are embedded into the image file when you save it in EPS format. Some page-layout applications such as QuarkXpress allow you to create clipping paths for images, but, be warned, these are only saved with the application file, so if your placed images are low-resolution FPO files that are to be replaced by the high-resolution versions, or if they are the preview files of a five-file DCS file, your clipping path will not have any effect.

Color model (3499) - the method of defining or modifying color. Although there are many proprietary color models, such as PANTONE, FOCOLTONE< TRUMATCH, TOYO, and DIC, the two generic models are those based on the way light is transmitted - the "additive" and "subtractive" color models. The additive color model is used, for example, in computer monitors, which transmit varying proportions of red, green, and blue (RGB) light we interpret as different colors. By combining he varying intensities of RGB light we can simulate the rage of colors found in nature and when 100% values of all three are combined, we perceive white, whereas if there is no light we see nothing or, rather, black. The subtractive color model is based on the absorption (in other words, subtraction) and reflection of light. For example, the printing inks of cyan, magenta, and yellow - if you subtract 100% values of either red, green, or blue from white light, you create cyan, magenta, or yellow.

RGB (3547) - red, green, blue - the primary colors of the "additive" color model, used in video technology (computer monitors, for example) and for graphics, such as for the web, and multimedia that will not ultimately be printed by the four-color (CMYK) process method.

Additive colors (3491) - the color model describing the primary colors of transmitted light; red, green, and blue (RGB). Additive colors can be mixed to form all other colors in photographic reproduction and computer display monitors.

CMY (3495) - cyan, magenta, yellow - the primary colors of the "subtractive" color model, created when you subtract red, green, or blue from white light. In other words, if an object reflects green and blue light, but absorbs, or subtracts, red, it will appear to you as cyan. Cyan, magenta, and yellow are the basic printing process colors.

CMYK (3496) - cyan, magenta, yellow, and black - (black is represented by the letter "k" for "key" plate). The four printing process colors based on the subtractive color model. In color reproduction, most of the colors are achieved by cyan, magenta, and yellow, the theory being that when all three are combined, they produce black. However, this is rarely achievable and would be undesirable since too much ink would be used, casing problems with drying time. For this reason black is used to add density to darker areas, while to compensate, smaller amounts of the other colors are used (this also has cost benefits because black is cheaper than colored inks). The degree of color that is "removed" is calculated by a technique known as "undercolor removal" (UCR)

Gamut (0738) - gamut, or "color space," describes the full selection of colors achievable by any single device on the reproduction chain. While visible spectrum contains many millions of colors, not all of them are achievable by all devices and, even if the color gamut's for different deices overlap, they will never match exactly - the 16.7 million colors that can, for example, be displayed on a monitor cannot be printed on a commercial four-color press. For this reason, various "color management systems" (CMS) have been devised to maintain consistency of color gamut's across various devices.

Dandy roll (2369) - a wire cylinder on a papermaking machine that impresses a watermark and laid lines into the paper while it is still wet

Couch (2367) - in papermaking, to lift sheets onto board or felt for drying, the name deriving from the board itself, called "couch"

Deckle (2370 & 2259) - the edging frame or strap on a papermaking mold or machine that confines or controls the pulp; deckle edge: the rough, uneven edge or untrimmed handmade paper; deckle edge effects are also applied mechanically to machine-made paper

Pulp (2397, 2364, 2393, 2553 & 2363) - the wet, raw material used for making paper, usually created from pounded plant fibers, especially wood, cotton, and linen; chemical pulp: pulp prepared from wood chips by treating them with chemicals to remove the non-cellulose material such as resin, ligneous matter, and oils. Also called "chemical wood," these pulps are used for making better grades of "wood-free" paper; mechanical (wood) pulp: untreated paper pulp used for low-quality papers such as newsprint. Also called ground-wood; wood-free paper: paper made without mechanical wood pulp; also called ground-wood free or pure; cellulose: a fibrous substance - originally obtained only from various plants such as cotton, hemp, flax, for example, but now obtained almost exclusively from wood; used as the basic substance in papermaking.

Rag (2316 &2315) - (rag paper/pulp): paper manufactured from cotton or linen fiber, using either new or recycled rags, and commonly used for writing and ledger papers; rag content: the amount of cotton or linen fiber found in a paper.

Calendar (2360) - a column of metal rollers at the end of the papermaking process that applies pressure to the paper; therefore closing the pores and giving the paper a sooth surface.

Watermark (2343) - a mark or design impressed in paper during the manufacturing process, sometimes used to make forgery of a document more difficult, such as in banknote printing.

Holdout (2288) - the resistance of certain glazed papers to the penetration of printing ink.

Gloss (2284) - the amount of light reflected by the surface of paper ("reflectance"). Machine-finishing under pressure through rollers can give a slight gloss.

Felt finish (2270) - a finish applied during papermaking as the sheet is dried on a special marking felt.

Finish (2275) - the surface of a paper, usually one that is coated or embossed.

Bond (2472) - a standard grade of strong, durable, and smooth writing paper, generally used for stationary printing.

Size (2402) - a gluelike substance that applied to paper or used in its manufacture to alter qualities such as absorbency.

Coated paper (2486) - a general term describing papers that have had a mineral coating applied to the surface - after the body paper was made, such as art, chromo, and enamel papers. Coated paper is also known as surface paper.

Uncoated paper (2339) - a paper without a mineral surface coating, but which is available in a variety of finishes from "antique" (rough) to "super calendared" (smooth)

Weight (2444) - the actual weight of a paper measured either in pounds per ream of 500 sheets or in grams per square meter (gsm, g/m2). However, paper weight is not necessarily an indication of substance. Alternatively, the thickness of the paper or board is measured in microns (one micron = one-millionth of a meter).

Caliper (2422) - a description of the thickness of paper or board, expressed as thousandths of an inch ("mils") or millionths of a meter ("microns")

Filters (2382) - a material used to improve the opacity, brightness, and printing surface of a paper. China clay, calcium carbonate, and other white mineral pigments are commonly used. Filler can also be used as an economic method of increasing bulk.

Mold-made paper (2301) - a manufactured paper that simulates handmade paper.

Laid (2522) - paper made with subtle parallel lines in its surface instead of the smooth surface of wove paper. The laid finish is impressed by a dandy roll on a fourdrinier machine.

Chain lines (2242) - visible lines on laid paper, caused by the wire gauze on the "dandy" roll, part of the "fourdrinier" papermaking machine.

Linen finish (2295) - paper embossed to resemble coarsely woven cloth.

Grain (2285 & 2286) - the prevailing direction and pattern of fibers in the manufactured paper.

Look-through (2297) - a term used when describing the opacity of a paper, whereby text or images printed on one side of a sheet are visible, through the sheet, from the other side. This may be caused by the use of incompatible inks and papers, but more often it is because the paper is too thin, also called show-through or see-through.

Opacity (7176) -

Trim (3353) - to cut printed sheets to the required size.

Ream (2452) - a standard quantity of paper, usually 500 sheets, although in some circumstances an extra number may b allowed for wastage, such as in a "printer's ream," which is 516 sheets.

M weight (2435) - the weight of 1,000 sheets of a given paper size, "m" being an abbreviation of the Latin mille, meaning one thousand.

Score (3336) - marking the line of a crease in paper or card so it can be folded cleanly; also called creasing

Fold (3282) - the folding of a single flat sheet to create a desired effect (accordion, French, gatefold, parallel, right-angle, and so on), or the folding of a printed signature/section of a multipage publication prior to gathering stitching, trimming, and binding.

Crease (3258) - an indented line impressed into paper or board that makes it easier to fold - used when making hinges for book covers, for example.

Bind (3082) - the process of joining and securing the assembled leaves of a printed work such as a book or pamphlet. There are many methods of binding, including mechanical methods, such as plastic comb binding and ring binding, and more conventional methods, such as Smyth-sewn, side sewn, section-sewn, saddle-sewn, and adhesive binding.

Basic weight (2417) - the weight, in pounds, of a ream of paper (500 sheets) cut to a designated size (basic size)

SWOP (2226) - Specifications for Web Offset Publication A system of standards developed for the printing industry to aid consistency in the use of color separation films and color proofing.

Die (3266) - a pattern or design of sharp blades that, when mounted on a press, are used to cut shapes out of paper or board.

Diecutting (3267) - a process in which paper or board is cut to a particular shape or design using a "die" on a "die press."