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- Glossary of Terms
Glossary A-F G-L M-R S-Z
Note: Many of the terms in this glossary are from the GATF Glossary of Graphic Arts Terms and GATF Guide to Desktop Publishing and are reproduced here with permission of PIA/GATF (Printing Industries of America/Graphic Arts Technical Foundation); www.gain.net.
Absorption
(1) The first stage of print drying in which a portion of the ink vehicle is absorbed by the paper. (2) An optical term for selective transmission or partial suppression of light.
Analox Rollers
A steel or ceramic ink metering roller. Its surface is engraved with tiny, uniform cells that carry and deposit a thin, controlled layer of ink film onto the plate. In flexo presswork, anilox rollers transfer a controlled ink film from the rubber plate (or rubber-covered roller) to the web to print the image. Anilox rollers are also used in remoistenable glue units and to create "scratch-and-sniff" perfume ads.
Author's Alterations (AA)
Changes requested by the author or author's representative after the original copy has been typeset. Alternative terms: author's corrections; artist's alterations.
Author's Proof
Prepublication copy sent to the author for approval. It is returned marked "OK" or "OK with changes."
Back Pressure
The force between the blanket cylinder and the impression cylinder that facilitates the transfer of the image from the blanket to the printing substrate. Alternative term: impression pressure.
Back Printing
Reproducing an image on the underside or second surface of a transparent sheet or film. Alternative terms: reverse printing; second-surface printing.
Banding
An electronic prepress term referring to visible steps in shades of a gradient.
Bar Code
A binary coding system using numerical series and bars of varying thicknesses or positions that can be read by optical character recognition (OCR) equipment. Bar codes are used in printing as tracking devices for jobs and sections of jobs in production.
Bearer Pressure
The force with which the bearers of opposed cylinders contact each other on an offset lithographic press
Black Printer
(1) The plate that prints black ink in four-color process printing. (2) The halftone film used to burn the plate that will print black ink or the printing screen used in process-color reproduction to print the color black and add detail to the print. The letter '"K" is often used to designate this color. Alternative term: key plate.
Blanket
(1) In presswork, a sheet of cork, felt, or rubber used on a press platen or impression cylinder to cushion the impression in printing. (2) In lithography, a rubber-coated fabric mounted on a cylinder that receives the inked impression from the plate and transfers (or offsets) it to the paper. Such blankets are also mounted on the impression cylinders of sheetfed gravure presses. (3) In stereotyping and electrotyping, a yielding resilient material for backing the mat or lead sheet that is pressed into the printing form to produce the mold. (4) Sheet of wool or rubber used in newspaper and poster work on the tympan of cylinder presses to secure a smooth but not too hard printing surface.
Blanket, Compressible
A blanket with a specially manufactured layer designed to "give" or compress, under pressure from the plate and impression cylinder. Compressible blankets resist smashing and usually print a sharper halftone dot. These blankets most often print with a plate-to-blanket squeeze of 0.004-0.006 in. (0.10-0.15 mm). Some produce optimum highlight and shadow detail with a squeeze as high as 0.008 in. (0.20 mm).
Blanket, Conventional
A hard, noncompressible blanket that bulges out on either or both sides of a nup under pressure.
Blanket Smash
Areas of low ink density in the press sheet image. The caliper of the blanket in these areas is too low to develop sufficient impression pressure against the plate or paper or both. Alternative term: blanket low spots.
Bleed
Pictures, lines, or solid colors that extend beyond the edge or edges of a page sot that when margins are trimmed, the image is trimmed even with the edge of the page.
Blocking
(1) Condition that occurs when printed sheets stick together because a wet ink film continues to hold them together after the ink should be dry. Blocking can also occur within rolls. (2) Mounting or nailing printing plates on permanent wooden supports.
Board
A heavy, thick sheet of paper or other ffibrous substance, usually with a thickness greater than 6 mil (0.006 in.).
Border
A printed line or design surrounding an illustration or other printed matter.
Butt
To adjoin two pieces of film or two colors of ink without overlapping.
Calibration
A process by which a scanner, monitor, or output device is adjusted to provide a more accurate display and reproduction of images.
Caliper
The thickness of a sheet of paper or other material measured under specific conditions. Caliper is usually expressed in mils (thousandths of an inch).
Camera-Ready Copy
All printing elements prepared to be photographed on the graphic arts camera: text type set in the correct point size and properly mounted to the page grid; headlines, copy blocks, and screened prints; keylines showing the exact size and position of halftones or four-color photographs to be stripped in; and spot color elements mounted to acetate overlays, properly registered over the black copy, and marked for screen percentage and colors. Manual pasteup techniques or computer-based pagination systems may be used to create the layout. Alternative term: camera-ready art.
Choke
A camera or contacting process whereby various images, such as type, are made thinner without changing shape or position. The image area remains essentially the same except for a narrow reduction around its perimeter. Chokes are used to provide a printing overlap between a color or tinted background and display matter, to outline letters, or to achieve other special effects when preparing negatives. Alternative term: "skinny".
Clay-Coated
Paper or board with an earthy material added to one or both sides to improve the quality of the printing surface.
Clip Art
Previously developed designs and graphics used in composing new artwork. Most clip art, which can be purchased in booklets or in electronic form, is in the public domain (copyright free) and can be used over and over again by anyone for any purpose once the initial purchase is made. Other clip art is purchased on a fee-per-usage basis.
Close Register
Term used to describe jobs with smaller register tolerances. Alternative term: tight register.
Closed Loop
A process in which all control functions have been automated, including sensing output errors and correcting the input to compensate for the error.
Color
A visual sensation produced in the brain when the eye views various wavelengths of light. Color viewing is a highly subjective experience that varies from individual to individual. In the graphic arts industry, lighting standards and color charts help ensure the accuracy of color reproduction.
Color Balance
(1) The correct combination of cyan, magenta, and yellow needed to reproduce a specific photograph without an unwanted color cast or color bias. (2) The specific combination of yellow, magenta, and cyan needed to produce a neutral gray in the color separation process. (3) The ability of a film to reproduce the colors in an original scene. Color films are balanced during manufacture to compensate for exposure to specific light sources.
Color Bar
A device printed in a trim area of a press sheet to monitor printing variables such as trapping, ink density, dot gain, and print contrast. It usually consists of overprints of two- and three-color solids and tints; solid and tint blocks of cyan, magenta, yellow, and black; and additional aids such as resolution targets and dot gain scales. Alternative terms: color control strip; color control bar.
Color Correction
(1) A photographic, electronis, or manual procedure used to compensate for the deficiencies of the process inks and color separation. (2) Any color alteration requested by a customer.
Color Management System
An electronic prepress tool that provides a way to correlate the color-rendering capabilities of input devices (e.g., scanners and digital cameras), color monitors, and output devices (e.g., digital color proofers, imagesetters, and color printers) to produce predictable, consistent color. Color management consists of three primary steps: (1) calibration of input devices, monitors, and output devices to known specifications, (2) characterization, which is a way of determining the color "profile" of a particular device, and (3) conversion, which performs the "color correction" function between color-imaging devices.
Color Sequence
The order in which colors are printed on a substrate as indicated by the order in which the inks are supplied to the printing units on the press. Color sequence determines how well the inks will trap on the substrate. Alternative term: color rotation.
Color Variation
A term used to describe changes that occur in the density of a color during printing as a result of deviations in the amount of ink accepted by paper or the amount of ink fed to the paper.
Colorfastness
How well a printed substrate retains its color under normal storage conditions and resists change as it ages or is exposed to light, heat, or other environmental influences. Alternative terms: color permanence, color retention, color stability.
Color-Key Color-Key
Trademark for a color proofing system that generates a set of process-color transparent overlays from separation negatives so that registration and screen-tint combinations can be checked before printing.
Console
The computer system workstation where operators perform specific tasks by executing commands through a keyboard. Modern presses have consoles that control inking, dampening, and plate register moves. The results of the operator's commands can be reviewed on a nearby monitor.
Continuous Improvement
Process of business management based on data tied to customer satisfaction.
Continuous Tone
An unscreened photographic image or art (such as a wash drawing) that has infinite tone gradations between the lightest highlights and the deepest shadows.
Control Chart
A trend diagram with an average line and statistically determined upper and lower control limits. The control limits represent the natural variation to be expected in the particular process, such as fountain solution pH and conductivity reading taken over a specific period of time. Various methods of interpretation are used to determine when the process is operating in a state of statistical control (with only natural or common variation present) and when it is operating out of statistical control (with assignable or special causes of variation present).
Converting
Any manufacturing or finishing operation completed after printing to form the printed item into the final product. Bagmaking, coating, waxing, laminating, folding, slitting, gluing, box manufacture, and diecutting are some examples. Converting units may be attached to the end of the press, or the operation may be handled by a special outside facility.
Copyfitting
Adjusting copy to the allotted space, by editing the text or changing the type size and leading.
Crop Marks
Small lines placed in the margin or on an overlay, denoting the image areas to be reproduced.
Cross-Grain
Folding at a right angle to the direction of the grain in the paper stock. Folding the stock against the grain.
Cut Score
A crease formed when the paper stock is partially slit.
Cyan
A blue-green color, complementary to red. Along with yellow and magenta, one of the three primary subtractive colors, or process colors used in the printing process. Cyan reflects blue and green light, while absorbing red.
Cyan Printer
(1) The plate used to print the cyan ink in process color reproduction. (2) The negative or positive film or color proof that indicates what image areas will print in cyan.
Data Compression
A software or hardware process that reduces the size of images so the they occupy less storage space and can be transmitted faster and easier. This process is accomplished by removing the bits that define blank spaces and other redundant data, and replacing them with a smaller algorithm that represents the removed bits. Data must be decompressed before it can be used.
Data Conversion
Techniques of changing digital information from its original code so that it can be recorded by an electronic device using different code. Data created in one software format may be converted to another before printing. Data must also be converted for various output devices, such as when RGB colors are converted to CMYK.
Data File
Text, graphics, or pictures that are stored electronically as a unit.
Decompress
To return compressed data to its original size and condition.
Delamination
The continuous splitting, or separation, of the paper's surface caused by the tack of the ink and the rubber blanket.
Densitometer
An instrument for measuring the optical density of a negative or positive transparency, or of a print. Reflection densitometers measure the amount of light that bounces off a photographic print. Transmission densitometers measure the fraction of incident light conveyed through a negative or positive transparency without being absorbed or scattered.
Density
(1) The light-stopping ability of an image or base material, sometimes referred to as optical density.
(2) A photographic term used to describe the tonal value of an area. A darker tone has a higher density than a lighter tone. A dry ink film has a higher density than a wet one.
(3) The specific gravity or weight per unit volume of paper.
Desktop
(1) Any computer or peripheral small enough to fit on top of a desk as opposed to a mainframe computer.
(2) The Macintosh (and now Windows) graphical user interface where screen elements are cast as icons or other representations that are meant to be analogous to a literal desktop. Examples of these elements include representing computer files as manila folders, and file delete functions as trash cans or recycling bins.
Desktop Color Separation (DCS)
A color file format that creates five PostScript files, one for each color (CMYK) and a data file about the image.
Dieboard
The plywood base into which the steel rule dies are inserted.
Diecut
A printed subject cut to a specific shape with sharp steel rules on a press.
Diecutting
Using sharp steel rules to slice paper or board to a specific shape on a specialized stamping press.
Direct Digital Color Proof (DDCP)
Proof printed directly from computer data to paper or another substrate without creating separation films first. Proof made with computer output device, such as laser or ink-jet printer.
Direct-To-Plate Technology
Those imaging systems that receive fully paginated materials electronically from computers and expose this information to plates in platesetters or imagesetters without creating film intermediates.
Dot Gain
The optical increase in the size of a halftone dot during prepress operations or the mechanical increase in halftone dot size that occurs as the image is transferred from plate to blanket to paper in lithography. Alternative terms: dot spread; ink spread.
Dots Per Inch (DPI)
A unit that describes the resolution of an output device or monitor.
Double-Sheet Detector
A device that can be set to stop the feeding action where the sheet-separation unit picks up two or more sheets simultaneously. Alternative terms: two-sheet detector; two-sheet caliper.
Drawdown
(1) A method of determining ink shade by placing a small amount of ink on paper and then using a spatula to spread it and produce a thin ink film. (2) The duration of time required to remove air from a vacuum frame to allow the original film and the contact film to achieve uniform contact before exposure.
Dry Trapping
The ability of a dry, printed ink film to accept a wet ink film over it.
Emulsification
Condition that occurs when a lithographic ink picks up too much dampening solution and prints a weak, snowflaky pattern. In extreme cases, the ink actually emulsifies in the water and shows up as small dots in the nonimage area. This is known as tinting.
Estimating
The process of determining approximate cost, specifying required quality and quantity, and projecting waste.
Feeder
(1) A mechanish which separates, lifts, and passes individual press sheets from the top of a pile table onto the feedboard to front stops. The sheets are laterally positioned on the feedboard by a side guide and then fed into the first printing unit. Alternative term: feeding head; stream feeder. (2) The device that forwards signatures or newspaper inserts, etc., through an in-line-finishing system.
File
A collection of digital information stored together as a unit on a computer disk or other storage medium and given a unique name, which permits the user to access the information. A file may contain text, images, video, sound, or an application program.
File Transfer Protocol (FTP)
The tool used to retrieve information in the form of electronic files from any number of computer systems linked via TCP/IP protocol. Users in the effect transfer copies of information found on remote computers either directly to their own computers either directly to their own computers or to a service provider's network and then to their own computers.
Folder Dummy
A mockup that shows the placement of page heads, the binding edge, and the gripper and side-guide edges, as well as page sequence and signature arrangement. Alternative term: folding dummy.
Font
A complete collection of characters in one typeface and size, including all letters, figures, symbols, and punctuation marks.
Four-Color Process Printing
The photomechanical reproduction of multicolor images achieved by overprinting specified amounts and areas of yellow, magenta, cyan, and black inks.
Front-End System
A grouping of interconnected keyboard terminals and related peripherals such as a central processing unit and storage devices that can operate independently of the output device, e.g., phototypesetter, line printer. The front-end system is used to enter, edit, and/or manipulate text and the coding used to drive the phototypesetter. It may operate on- or off-line with the output devices.
Grain Direction
(1) In papermaking, the alignment of fibers in the direction of web travel. (2) In printing, paper is said to be "grain-long" if the grain direction parallels the long dimension of the sheet. The paper is referred to as "grain-short" if it parallels the short dimension of the sheet. (3) In book binding, the grain direction of all papers used must run parallel to the book backbone.
Gang
(1) A grouping of different or identical forms arranged to print together in one impression. Alternative terms: gang up; gang run; gang printing. (2) Multiple photographic images exposed as one unit. Alternative term: photocombining.
Ghosting, Mechanical
Condition that occurs when the ink film on the press sheet shows abrupt variations in color densities, especially when a narrow solid printed ahead or behind a wider solid consumes much of the ink on the form rollers. Alternative term: ink starvation ghosting.
Glossmeter
An instrument used to measure the specular reflectance from a surface at a given angle.
Grain
(1) The distribution, coarseness, and size of silver particles in photographic emulsions and images. (2) The roughened or irregular surface of a printing plate. (3) In papermaking, the machine direction, or the direction in which the fibers lie.
Gray Balance
The values for yellow, magenta, and cyan that produce a neutral gray with no dominant hue when printed at a normal density.
Gripper
(1) The metal clamps or fingers located on impression cylinders and transfer cylinders, that grasp and hold a sheet while being transported through the press. (2) The reference edge of a layout, film flat, or print plate that corresponds to the sheet edge held by the grippers on the press.
Gripper Edge
The leading edge of a sheet when it is being moved, in the grip of mechanical fingers, to and through the image transfer, or impression, operation on a sheetfed press.
Guide Edge
The side of a sheet at right angles to the gripper edge that is used to control the lateral (side-to-side) position of the sheet as it travels through the press or folder.
Halftone
A printed reproduction of a continuous-tone image composed of dots that vary in frequency (number per square inch), size, or density, thereby producing tonal gradations. The term is also applied to the process and plates used to produce this image.
Hazard Communication Standard
An OSHA regulation that requires chemical manufacturers, suppliers, and importers to assess the hazards of the chemicals that they make, supply, or import, and to inform employers, customers, and workers of these hazards through material safety data sheets (MSDS).
Heat Sealing
The converting operation in which two or more surfaces are fused together using specific heat, time, and pressure.
Hickey
An imperfection on a printed sheet caused by dirt, hardened ink, or other unwanted particles that cling to the press, blanket, or plate during lithographic printing. Hickeys appear as either a small, solid printed area surrounded by a white halo, or an unprinted spot surrounded by printed ink.
Hicky-Picking Roller
A roller that has synthetic fibers embedded in its surface, to help it remove hickeys from the surface of an offset printing plate or to fill in the white ring on the plate surface. This roller replaces one of the ink form rollers.
Holdout
The extent to which paper resists or retards the penetration of the freshly printed ink film.
Hot Melt
(1) A molten wax or plastic adhesive material that is applied with a roller or knife or through the casting or extrusion method at elevated temperatures in liquid form. It solidifies upon cooling and imparts high gloss and good barrier properties to paper and board.
(2) A bookmaking glue that is solid at room temperature and must be heated to achieve liquidity.
Humidity, Relative
The amount of moisture present in the air, expressed as a percentage of the amount of moisture required to saturate the air at a given temperature.
Hunter L,a,b Values
Scales developed by Hunter Associates Laboratory, Inc. that are widely used to define and measure color.
Imagesetter
A device used to output fully paginated text and graphic images at a high resolution onto photographic film, paper, or plates.
Imposition
Assembling the various units of a page before printing and placing them on a form so that they will fold correctly. Alternative term: image assembly.
Imprinting
Reproducing a few lines of type, such as a company's name and address, on previously printed sheets.
Ink Agitator
A revolving cone-shaped device that moves from one end of the fountain to the other keeping the ink soft and flowing.
Ink Film Thickness
The depth of a wet ink film in the ink train or on the ink form rollers.
Ink Fountain
The trough on a printing press that holds the ink supply to be transferred to the inking system. The operator controls ink volume from adjustment screws or keys on the fountain or from a remote console. The ink fountain consists of an ink reservoir, ink keys, and an ink pan or fountain roller.
Ink/Water Balance
In lithography, the appropriate amounts of ink and water required to ink the image areas of the plate and keep the nonimage areas clean.
ISO 9000 (Q90)
"Quality Management and Quality Assurance Standards" Guidelines for Selection and Use. (1) This standard explains fundamental quality concepts, defines key terms, and provides guidance on selecting and using the ISO 9001, 9002, and 9003 standards. (2) A series of international standards (ISO 9000, 9001, 9002, 9003, and 9004) developed in 1987 by the ISO Technical Committee (TC) 176 on quality systems. This series, together with the terminology and definitions contained in ISO Standard 8402, provide guidance on the selection of an appropriate quality management system for a supplier's operation. These standards are not particular to any industry, product, or service. In the United States, the ISO 9000 Series has been adopted as the ANSI/ASQC Q90 Series.
ISO 9002 (Q92)
"Quality Systems" Model for Quality Assurance in Production and Installation. This standard addresses the prevention, detection, and correction of problems during production and installation. More extensive and more sophisticated that ISO 9003, it is typically the standard under which printers pursue registration.
JPEG
The compression scheme based on the discrete cosine transform (DCT) lossy compression algorithm that is a defacto standard on the Internet. Named for the Joint Photographic Experts Group, which developed this compression scheme. JPEG allows the user to control the compression ratio and reproduction quality at the point of compression. It can also incorporate other algorithms, such as one-dimensional modified Huffman compression for lossless compression.
Kerning
Manipulating type character widths and white space to achieve aesthetically pleasing results.
Knockout
Type that appears as unprinted stock on a black or dark colored background. Alternative terms: reverse; dropout.
Lines Per Inch
Designates the resolution of a halftone screen. Screens with a higher number, such as 120 or 133, have a higher resolution than screens with lower numbers, such as 65 lines per inch. Alternative term: screen ruling.
Offset Printing
An indirect printing method in which the inked image on a press plate is first transferred to a rubber blanket, that in turn "offsets" the inked impression to a press sheet. In offset lithography, the printing plate has been photochemically treated to produce image areas and nonimage areas receptive to ink and water respectively.
Magenta
The subtractive transparent primary color that should reflect blue and red and absorb green light. It is one of the four process-color inks used in the printing process. Alternative term: process red.
Magenta Printer
(1) The plate that prints magenta ink. (2) The color separation film that will be used to produce the magenta printing plate.
Midtones
The range of tonal values between highlight and shadow areas. Alternative term: middletones.
Misregister
Printed images that are incorrectly positioned, either in reference to each other or to the sheet's edges.
Moire
An undesirable, unintended interference pattern caused by the out-of-register overlap of two or more regular patterns such as dots or lines. In process-color printing, screen angles are selected to minimize this pattern. If the angles are not correct, an objectionable effect may be produced.
Multicolor
Two or more colors.
Multicolor Press
Two or more connected printing units (each with its own inking and dampening system), a feeder, a sheet transfer system, and a delivery. Two or more colors can be printed on one side of a sheet during a single pass through the press.
Offline Converting
Coating, cutting, folding, embossing, stamping, or otherwise altering newly printed sheets or rolls of material to form the final printed piece or product on a machine separate from the printing press. Printing plants may have dedicated converting equipment or they may send the work to companies that specialize in converting.
OK Sheet
A press sheet that closely matches the prepress proof and has been approved by the customer and/or production personnel. It is used as a guide to judge the quality of the rest of the production run.
Operating System
The master program that a computer needs to start up and perform basic tasks. It allows the computer to control itself and perform other functions, such as managing memory allocation for application software and data files.
Overprint
(1) A color made by printing any two of the process inks (yellow, magenta, and cyan) on top of one another to form red, green, and blue secondary colors. (2) Solid or tint quality control image elements that are printed over or on the top of previously printed colors. Overprint patches are used to measure trapping, saturation, and overprint color densities. Like other quality control elements, overprints may be measured from a color bar in the trim of a press sheet or from the printed image itself.
Overrun
The quantity of printed copies exceeding the number ordered to be printed. Trade custom allows a certain tolerance for overruns and underruns.
Packing
(1) The procedure for producing the pressure between the plate and blanket cylinders. (2) The paper or other material that is placed between the plate or blanket and its cylinder to raise the surface to printing height or to adjust cylinder diameter to obtain color register in multicolor printing.
Pantone Matching System (PMS)
The most commonly used ink-mixing and color-reference formula.
Plate
A thin metal sheet that serves as the image carrier in many printing processes.
Platemaking
Preparing a printing plate or other image carrier from a film or flat, including sensitizing the surface if the plate was not presensitized by the manufacturer, exposing it through the flat, and developing or processing and finishing it so that it is ready for the press.
Point Size
Specifying the height of the body of a typeface in units of linear measure equal to 0.0138 in. Alternative term: type size.
Portable Document Format (PDF)
A computer file format that preserves a printed or electronic document's original layout, type fonts, and graphics as one unit for electronic transfer and viewing. The recipient uses compatible "reader" software to access and even print the PDF file.
PostScript
Adobe Systems, Inc. tradename for a page description language that enables imagesetters and other output devices developed by different companies to interpret electronic files from any number of personal computers (front ends) and off-the-shelf software programs.
PostScript, Encapsulated
A file format used to transfer PostScript image information from one program to another.
Preflighting
An orderly procedure using a checklist to verify that all components of an electronis file are present and correct prior to submitting the document for high-resolution output.
Pressrun
(1) The total of acceptable copies from a single printing. (2) Operating the press during an actual job.
Proof
A prototype of the printed job made photochemically from film and dyes, or digitally from electronic data (offpress proofs) or photomechanically from plates mounted on a printing press (a press proof). A proof serves as a sample for the customer and as a guide for the press operator.
Proof, Progressive
A set of press proofs from the separate plates used in process color work, showing the printing sequence and the result after each additional color has been applied. (Press proofs of each individual process color and black; each combination of two process colors; each combination of three process colors; and all four process inks combined.) Alternative term: progs.
Register
The overall agreement in the position of printing detail on a press sheet, especially the alignment of two or more overprinted colors in multicolor presswork. Register may be observed by agreement of overprinted register marks on a press sheet. In stripping, film flats are usually punched and held together with pins to ensure register. The punched holes on the film flat match those on the plate and press specified for the job. Alternative term: registration.
Register Marks
Small reference patterns, guides, or crosses placed on originals before reproduction to aid in color separation and positioning negatives for stripping. Register marks are also placed along the margins of negative film flats to aid in color registration and correct alignment of overprinted colors on press sheets.
Resolution
(1) The density of dots or pixels on a page or display usually measured in dots per inch. The higher the resolution, the smoother the appearance of text or graphics. (2) The precision with which an optical, photographic, or photomechanical system can render visual image detail. Resolution is a measure of image sharpness or the performance of an optical system. It is expressed in lines per inch or millimeter.
Spray Powder
Ground starch particles sprayed onto sheets to keep the ink on each press sheet from direct contact with the ink on another sheet in the delivery.
Spread
(1) A line image with edges that have been moved slightly outward to allow a color or tint to intentionally overlap. Alternative term: "fatty" (2) An image that extends across two facing pages in a book or magazine, crossing over the binding. Alternative terms: crossover; reader's spread.
Scalable Fonts
Fonts that can be scaled to any size from a single set of masters without loss of quality.
Scanner
(1) An electronic device that uses a light beam to examine color transparencies and isolate each process color on an individual piece of film, or photographic separation, to be used on the reproduction process. (2) Flatbed electronic devices are used in conjunction with desktop publishing systems to scan line art, logos, photographs, and, with optical character recognition (OCR) capabilities, typewritten or printed text supplied by the client. After the artwork, photographs, and text have been scanned into the system and stored on disk, they are called up on the computer screen and manipulated and assembled in page form using software and then output as a single unit (on paper or film) from the imagesetter.
Screen Angle
The position of the rows of dots on halftone screens in relation to a reference grid with horizontal and vertical lines. The most dominant color screened is positioned at a 45 degree angle to the reference grid.
Screen Fonts
Digital typefaces used for screen display.
Side Guide
A device that serves as part of the register system of a sheet-fed printing press. Side guides move the sheet sideways to facilitate register.
Slitter Dust
Small particles of fiber, coating, or both that are chipped off during slitting and may adhere to the edge of the sheet. Slitter dust may interfere with subsequent converting operations.
Slur
A printing defect appearing as a blurred elongation of a printed dot.
Spectrophotometry
The science of measuring color by analyzing the reflection or transmission of samples at specified points across the electromagnetic spectrum. The spectrophotometric curve is the most precise means for specifying colors since metameric pairs can be distinguished.
Split Fountain
A divided ink fountain, or the use of dividers, to provide separate sections capable of holding two or more colors of ink, to permit the printing of two more colors, side by side, in one pass through the press.
Spot Color
The use of one or more extra colors (in addition to cyan, magenta, yellow, and black) on a page, used for a number of purposes including highlighting specified page elements.
Spray Powder
Ground starch particles sprayed onto sheets to keep the ink on each press sheet from direct contact with the ink on another sheet in the delivery.
Squeeze
Printing pressure between the plate and blanket cylinders. It is expressed as the combined height of the plate and blanket over their respective bearers on a bearer-contact press and as the combined height of the plate and blanket over their respective bearers minus the distance between the bearers on a nonbearer-contact press.
Step-and-Repeat
Exposing multiple images onto a single film or a single printing plate from a single negative or positive flat. Special step-and-repeat contact frames, projection platemaker, and multi-imaging cameras are used to automate this process.
Stock
The paper or other substrate to be printed.
Substrate
Any base material with a surface that can be printed or coated.
Tensile Strength
The amount of stress needed to break paper.
Text
The body matter of a page composed in column or paragraph form. Display matter, headings, and illustrations do not fall into this category.
Throughput
The capacity of a printing system to deliver printed products, usually expressed in sheets per hour, impressions per hour, feet per minute, pages per minute, or square feet per hour.
Tinting
Ink pigment particles that bleed into the dampening solution causing an overall tint to quickly appear on the unprinted areas of the sheet. This tint may appear on the nonimage areas of the plates but can be washed off with water and a sponge; however, it reoccurs when printing is resumed.
Tone
The degree of lightness or darkness in any given area of a print. Alternative term: tone value.
Toning
Intensifying or changing the degree of lightness or darkness in any area of a photographic print after processing. Toners are used to produce various shades of brown and blue.
Total Quality Management (TQM)
A management approach to long-term success through customer satisfaction. TQM is based on the participation of all members of an organization to continuously improve processes, products, services, and the company culture.
Transfer Cylinders
The press cylinders that convey paper from one printing unit to another. Paper grippers mounted on the transfer cylinders hold the paper as it travels on the cylinder.
Trap, Apparent
A relative indication of how well (or how poorly) an overprint ink stick or "traps" over the first-down ink as compared to how well the overprinted ink traps on bare paper. Apparent trap is usually measured only when printing a wet ink on top of another wet ink.
Trapping
(1) Printing a wet ink over a previously printed dry or wet ink film. (2) How well one color overlaps another without leaving a white space between the two or generating a third color.
Trapping, Dry
Printing overprints, or one color on top of another, when the first color is already dry. Printing multicolor work on a single-color press.
Trapping, Wet
Overprinting one wet ink film over another wet ink film. Wet trapping occurs in multicolor printing on presses with multiple printing units. A wet trap can be measured with a densitometer that has a trap-reading function or mode. Process solid ink patches and overprint ink patches are read with a densitometer. The densitometer then uses a formula to create a trap value expressed in percent. A 100% trap would be a perfect ink trap. This never happens in normal wet ink overprinting; the values are less than 100%.
Trend Chart
A simple graph on which measures of a particular variable are plotted over time, such as hours of machine downtime or the amount of paper waste generated each week. Alternative terms: r chart; run chart.
Type
The letters, numerals, and special figures produced in different faces and sizes by various composition methods.
Typeface
A distinctive type design, usually produced in a range of sizes (fonts) and variations, including bold and italic.
Typesetting, Digital
Imagesetters and third-generation phototypesetting machines that eliminate the need for film fonts by storing digital codes in the computer unit and producing type characters as microscopic dots.
Typo
An unintentional error made during keyboarding or by the typesetting machine itself. The latter is often referred to as a machine error.
Underrun
Producing fewer printed sheets than specified or ordered. Trade customs permit a standard tolerance for overruns or underruns.
Variation
The inevitable difference among individual outputs of a process. Variation can be classified in terms of natural causes (common, normal) or assignable (special, abnormal). For example, some dot gain occurs naturally during prepress and presswork, but dot gain caused by improper plate-to-blanket squeeze or an excessive ink film thickness is abnormal.
View File
A low-resolution electronic file containing the actual data used to form the final output page. Its primary use is to drive (display an image) on the workstation's color monitor. The view file can be output to continuous-tone material to provide a low-resolution proof of a quality slightly better than that displayed on the workstation monitor.
Vignette
(1) A halftone, drawing, or engraved illustration in which the background gradually fades away from the principal subject until it finally blends into the nonimage areas of the print. (2) an image segment with densities varying from highlight to white. (3) Any small decorative illustration or design used to ornament a book, periodical, or other printed matter, especially before the title page and at the ends of sections or chapters.
Virus
A computer program specifically designed to harm a computer's hard drive or certain applications stored therein. Viruses are transported across networks or through shared disks or via Internet downloads to computers lacking virus protection.
Viscosity
A measure of how well a printing ink, glue, or other fluid resists flowing. Viscosity is the opposite of fluidity.
Volatile Organic Compound (VOC)
Any organic compound that significantly participates in photochemical reactions. Presence in emissions (pounds/day) by which clean air standards are measured (e.g., 15 pounds VOC emissions per day). The cleaning solvents used in the printing industry are among those chemical substances that are subject to governmental regulations regarding safety hazards because of VOC emissions.
Washup
The process of cleaning the rollers, form or plate, and fountain of a press with solvents to remove all ink as required after a day's run, or during a run for ink color changes.
Waste, Converting
The trimmings generated when paper is cut into various shapes and sizes.
Water-Based Ink
An ink containing a water-soluble or water-dispersible resin instead of petroleum derivatives.
Water-In-Ink Emulsion
An emulsion of ink and water in which the water is broken up into fine droplets in the ink.
White Space
The area in printed matter that is not covered by type and illustrations.
Yellow Printer
In process color printing, the plate used to print the yellow ink image, or the film used to produce the plate that prints the yellow image.
Zahn Cup
A device used to measure the viscosity of flexographic or gravure inks.
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