GLOSSARY OF PRINTING TERMS

ANILOX ROLLER
A steel or ceramic ink metering roller on a flexographic press that transfers a thin, controlled ink film from the fountain roller to the rubber printing plate. Tiny, uniform cells engraved on the roller’s surface carry the ink.

ANTISETOFF COMPOUND
An ink additive that prevents setoff, which occurs when ink from sheets in the delivery pile stick to the backs of other sheets.

ANTI-SKINNING AGENTS
Chemical substances which retard skin formation on the surface of oxidizable oil or ink. They are frequently called antitoxins.

ASE SHEET
A strong, or heavy, sheet to which typeset copy is adhered, along with artwork, and made into a paste-up, or mechanical.

BIMETAL PLATE
A lithographic printing plate made from two metals, one forming the ink-receptive image area (usually copper) and one forming the water-receptive non-image area (chromium, stainless steel, aluminum, zinc, etc.).

BLANKET CYLINDER
The large-diameter roller on a lithographic press that carries the offset rubber blanket, placing it in contact with the inked image on the plate cylinder and then placing it in contact with the substrate to offset the ink image.


CAPILLARY ACTION
The movement of a liquid with or against the law of gravity, into a very small opening, usually tubular in shape, or as in a surface of closely matted very fine fibers. Liquid penetration and flow rate in porous surfaces is dependent on pressure, surface tension, and radius of the opening, among other factors.

CAPILLARY FILM

A presensitized, uniformly coated stencil film that is adhered to the screen fabric – still wet following the degreasing rinse – and draw up into the mesh by capillary action, prior to exposure and development.

CATHODE RAY TUBE (CRT)

An electronic vacuum tube with a heated cathode that generates electrons and with multiple grids for accelerating the electrons to a flat screen at the end of the tube. The screen coating fluoresces wherever the electrons strike it, giving off light. CRTs are used as monitors in video display terminals (VDTs) and as an output light source in third-generation pnototypesetters.

CHARGE-COUPLED DEVICE (CCD)

A component of an electronic scanner that digitizes images. It consists of a set of image-sensing elements (photosites) arranged in a linear or area array. Images are digitized by an external light source that illuminates the source document, which reflects the light through optics onto the silicon light sensors in the array. This generates electrical signals in each photosite proportional to the intensity of the illumination.

CHILL ROLLERS

The section on a web offset press where heatset inks are cooled below their setting temperature. It is located after the dryer.

COATING

1. A layer of material applied to a substrate in a relatively unbroken film, with no definite design or pattern except that dictated by the shape of the substrate; 2. A screen printed material, pigmented

or clear; applied to a substrate and forming a continuous film.

COLOR CORRECTION

Any of several methods used to modify or improve the color fidelity of a continuous tone original or screened separations, by masking, dot-etching or re-screening, etc. Primarily done to compensate for impurities in the ink color.

COLOR ELECTRONIC PREPRESS SYSTEM (CEPS)

A computer-based image manipulation and page-makeup system for graphic arts applications. These systems produce, at very high speed, complete sets of separations to single- or double-page size, with all illustrations, tints, and rules in their correct locations. Some systems also integrate text.

COLOR SEPARATION

1. A manual technique of visually interpreting the color areas in art work and providing a separate transparency, hand rendered for each – used in separating colors in line rendered art; 2. A photographic technique involving photographing original continuous tone colored art through a series of filters, each to provide negatives representing the colors used in rendering the

original; 3. An electronic scanning technique using laser technology to provide a set of halftone negatives (or positives) representing the colors in the original artwork.

COMMON-IMPRESSION CYLINDER (CIC)

A large cylinder that holds or supports the substrate and has several color stations positioned around it. On some web and sheetfed offset presses, the common-impression cylinder is in contact with several blanket cylinders. This configuration is used to print multicolor work on one side of the web or sheet.

COMPOSITE

An art layout in which all color separations are shown in one piece of copy, usually black and white.

CONTINUOUS TONE

Copy or image containing a range of tones from light to dark such as that found in photographs, in which the various tones blend smoothly into lighter or darker adjacent tones without visible boundaries, and without having been photographed through a halftone screen.

CONTINUOUS TONE ART

An original such as a wash drawing or conventional photograph that has light and shadow gradations which blend smoothly.

CONTINUOUS TONE NEGATIVES

Those negatives made in a camera on sensitized film without the aid of halftone screens.

CURE

The resolving of coating material into a usable or specific
CYAN

Blue green color, complimentary to red and one of the three primary subtractive pigment colors, the other two being yellow and magenta. Cyan reflects blue and green light, while absorbing red.

CYLINDER PRESS

1. A screen printing press so constructed that the substrate, wrapped around a rotating drum, contacts the printing surface of a moving printing screen, being discharged onto a conveyor after printing; 2. A press used for die cutting.

DAMPENING SYSTEM

A series of rollers that moisten the printing plate with a metered flow of a water based solution containing such additives as acid, gum arabic, and isopropyl alcohol, or other wetting agents.

DEFINITION

1. A subjective measure of the overall quality, resolution, and acutance of a printed shape against the substrate or back-ground; 2. Clarity of detail.

DELIVERY

(1) The section of a printing press that receives, jogs, and stacks the printed sheet. (2) The output end of bindery equipment.

DESKTOP PUBLISHING

A compact publishing system that includes a personal computer (usually with a color monitor); word processing, page-makeup, illustration, and other software; digitized type fonts; a laser printer; and other peripherals, such as an optical image scanner. It is used mostly to produce low-volume, low-resolution work. More sophisticated software and systems can yield higher quality artwork and text, which can be merged and output as color-separated, registered film on an imagesetter.

DIAZO

A photosensitive chemical or process by which screen printing emulsions can be made sensitive to actinic light. Images are formed by a molecular dye process.

DIAZO EMULSION

a light sensitive emulsion for making a screen printing stencil that is sensitized with diazo chemicals rather than bichromates.

DIE

Any of various tools designed for cutting in a predesigned pattern or form by utilization of pressure or mechanical motion to contact the cutting edge to the surface to be cut.

DIFFUSION TRANSFER

Photographic method of processing an exposed sheet of sensitized paper in contact with a receiver sheet.

DIGITAL HALFTONE

A halftone produced with a scanner, or video digitizer, computer system, and imagesetter as opposed to a conventional halftone made with a contact halftone screen and a process camera.

DIRECT COSTS

Those costs which can be directly applied to a job, e.g., the labor used to produce a job; the materials used to produce a job.

DIRECT DRIVE

A feature of some screen printing presses, where the surface to be printed is synchronized with screen/squeegee movement, as by a rack and gear driven mechanism, etc.

DIRECT EMULSION

A liquid polymer emulsion used as a screen printing stencil after being photosensitized, coated onto a stretched screen, exposed to actinic light, developed and washed out.

DIRECT HALFTONE

A halftone negative made by direct exposure through a halftone screen.

DIRECT/INDIRECT PHOTOSCREEN STENCIL

A stencil made by adhering a gelatin coated sheet to the underside of the stencil fabric

with a photo-sensitized emulsion applied from the upper side through the fabric. On drying, the screen is exposed through a positive, developed, and the plastic support sheet stripped away.

DIRECT LABELING

The imprinting of a label directly on the surface of a bottle, package, or other object.

DIRECT LABOR

Those job functions strictly involved in the direct production of a product or conversion process.

DIRECT LABOR COST

Equals the total direct labor for a specific time period, divided by the quantity of material produced or converted during that period.

DIRECT LITHOGRAPHY

A lithographic process in which the plate and printing surface are brought into contact. Its use is diminishing in favor of offset lithography.

DIRECT PHOTOSCREEN STENCIL

A photoscreen stencil made by coating light sensitive emulsion onto stretched screen printing fabric, allowing it to dry, then exposing to a film positive preparatory to processing into a screen printing stencil.

DIRECT POSITIVE

A photographic transparent positive made by exposing copy in direct contact with film, having eliminated the necessity of making a negative first.

DIRECT PRINTING SCREEN

A direct printing screen is made by coating the screen printing fabric with an emulsion, usually pre-sensitized, allowing the coating to dry, then exposing to a positive and developing to form the stencil.

DIRECT STENCIL

See Direct Printing Screen.

DOCTOR BLADE

A scraping blade used to spread an even film of liquid or near liquid onto a surface. In screen printing it is called a Flood Bar.

ELECTROSTATIC DECORATING

A method of decorating an article utilizing the phenomenon of opposite electrically charged particles attracting each other. Flock, ink particles, etc., may be applied to substrate by positively charging the particles and negatively charging the substrate.

ELECTROSTATIC FILM

A plastic sheet that has been electrostatically charged so that it “clings” to any highly polished surface without adhesive, offering easy removal and reuse capability.

ELECTROSTATIC PLATE

An organic photoconductor that serves as an offset lithographic image carrier.

EMULSION

A liquid or semi-liquid compound type used in (a) silver halide photographic film, (b) photostencil process, or (c) textile inks. The compound is usually made from two or more ingredients, (such

as oil or lacquer and water in ink manufacture) which do not intermix readily in their primary state.

EMULSION COATER

A tool, typically a smooth metal trough, used to spread thin layers of direct emulsion on a pre-stretched screen. Also called a “Scoop Coater.”

EMULSION SIDE

The side of the indirect photosensitive stencil, or photographic film, which is coated with the emulsion.

EMULSION SPEED

Of a photographic film, the rate of response to light under standard conditions.

EMULSION UP

Refers to a photographic film positive (or negative) in which the emulsion side is placed facing up, for contact with a photostencil. In most, but not all cases, the copy should read from left-to-right position.

FILLER

1. An inert substance added to plastic or ink formulations to reduce cost and/or to provide bulk; 2. A material, generally nonfibrous, added to a paper mixture to increase smoothness or opacity.

resisting deformation by heat or flame.

FILM IMAGE ASSEMBLY

Positioning, mounting, and securing various individual films to one carrier sheet in preparation for platemaking. Also called stripping.

FINISHING

Term generally applied to encompass post-press operations such as trimming, die cutting, bindery, etc.

FLAT

The stripped-up film positive or negative used to make a photostencil.

FLAT-BED PRESS

A screen printing press in which the substrate is placed on a flat surface prior to printing in contact with a flat printing screen which is attached by a carrier held on vertical posts or in clamshell fashion.

FLATBED SCANNER

A scanner on which the original is placed on a horizontal table instead of a rotary drum.

FLEXOGRAPHIC PRINTING

Formerly called analine printing. A method of rotary printing utilizing flexible rubber plates and rapid drying fluid inks.

FOLDER

A machine that bends and creases printed sheets of paper to particular specifications during binding and finishing.

FOUNTAIN

The ink reservoir on a screen printing press.

FOUNTAIN ROLLER

The roller in the ink fountain which, by revolving, agitates the ink.

GALLEY

(1) Phototypesetter output, usually in single columns of type on long sheets of photographic paper, which serves as preliminary proofs. (2) The final typeset (or imageset) copy output to photographic paper, or film. (3) A long, shallow tray used to store and proof handset type.

GRAVURE CYLINDER

The image carrier in gravure printing.

GRAVURE PRINTING

An intaglio printing process in which the ink is carried in minute etched “wells” on the plate, the excess being removed from the surface by a doctor blade. Rotogravure printing is done on web stock with cylindrical plates. Sheet fed gravure printing involves the feeding to the printing plate of individual sheets of substrates.

GRIPPER EDGE

A narrow area along the edge of a printing sheet which allows space for mechanical fingers or suction cups to attach to move the sheet through the printing operation and/or to remove the

sheet from the press to the dryer conveyor. Also called Gripper Margin.

GRIPPERS (Gripping Fingers)

Mechanical fingers on a press, or small vacuum suction cups, designed to pick up substrates from the stockpile and move them to printing base or from printing base to dryer or other conveyor. The attachment of the fingers to the substrate is temporary and releasable.

HALFTONE

A print in which details and dark and light tones are represented by dots of varying sizes in relationship to the tones or shades which they must portray. Small dots form light tones, larger

dots form darker tones.

HALFTONE DOT COUNT

See Halftone Line Count.

HALFTONE DOT RESOLUTION

The ability of a printing screen to accurately reproduce a halftone dot (or dots) of a specific shape and size (or sizes).

HALFTONE FILM

Any camera film suitable for use in making halftone negatives.

HALFTONE LINE COUNT

A means of determining the fineness of coarseness of a halftone screen, negative, positive, or stencil. The halftone dots, regardless of size, are equidistant from others on their centers, thus, located in parallel lines. A count of lines per inch indicates fineness, i.e., a screen designated as 65 line has 65 lines of dots per inch and is designated a coarse screen, while a screen designated as 150 line (150 lines per inch) is relatively fine.

HALFTONE NEGATIVE

A film negative in which the halftone dots form the image corresponding to the original continuous tone art.

HALFTONE PLATE

A printing screen with which halftone printing can be accomplished. The term plate is technically incorrect, though sometimes used.

HALFTONE POSITIVE

A film positive usually made by exposing film through a halftone negative to obtain the dot structure. In some instances it may be made on film that develops out to positive, thus avoiding the negative step.

HALFTONE PRINTING

A technique by which an image which has been broken up photographically into a structure of tiny dots, each equidistant from others on centers, but varying in size in relation to light and dark areas, can be printed to preserve the gradations of tone by virtue of larger dots producing darker tone areas. The dots are smaller than can be normally noticed by the unaided eye.

HALFTONE REPRODUCTIONS

Printed matter produced by using halftone photomechanical techniques.

HALFTONE SCREEN

A pattern on a transparent sheet which is placed between film and subject (artwork) to break up the continuous tone reflections from the art into halftone dots on exposure in a camera. Glass screens must be spaced away from the film, having cross-hatched lines etched into the surface. Contact screens, made photographically with vignetted dot structure, are placed in contact with the film.

HEATSET PRESS

A web offset press that includes a hot-air dryer and chill rolls.

HIGHLIGHT DENSITY

The density in that portion of a halftone negative or positive which ultimately results in the printing of the highlight area.

HIGHLIGHT DOT

Normally the largest dot in the film negative, or the smallest dot in the film positive and photoscreen stencil that defines a highlight area in the reproduction.

HIGHLIGHT END

Term relating to that portion of the halftone positive or the printing screen which prints the highlight areas of a halftone illustration.

HIGHLIGHT EXPOSURE

The normal exposure required to produce correct highlights in a halftone negative. See also Main Exposure.

HIGHLIGHTS

The lightest areas of original copy or reproduction with respect to depth of color.

IMAGESETTER

A device used to output fully paginated text and graphic images at a high resolution onto photographic film, paper, or plates.

IMPRESSION

1. The pressure of type or printing plate as it comes into contact with the substrate; 2. A screen print of one color – a single print.

IMPRESSION CYLINDER

The large-diameter roller on a lithographic printing press that provides the pressure needed to transfer ink to paper.

IMPRESSION PASS

See Printing Stroke.

IMPRESSION TIME

The time required for a squeegee to accomplish the length of stroke necessary to provide a complete imprint on the substrate.

IMPRINTING

1. The result of transferring an image, especially by pressure; 2. A technique by means of which a portion of a substrate can be printed or coated and another print applied over the area.

INDIRECT PHOTOSTENCIL PRINTING SCREEN

A printing screen made by exposing to actinic light a photosensitive polymer or gelatin, which has been coated onto a plastic support sheet, through a film positive; the film is developed out and then adhered, via the gelatin (polymer) side, to the fabric. Once dry, the plastic support sheet is removed for printing.

INDIRECT PRINTING SCREEN

1. A printing screen made by exposing a photosensitive emulsion which has been coated onto a plastic support sheet through a positive, developing the stencil on the support sheet, then adhering the emulsion side to the fabric. The support sheet is removed when the stencil is dry; 2. A printing screen made with the use of a hand-cut (knife-cut) stencil, prepared prior to adhesion to the stretched screen fabric.

INDIRECT STENCIL

A photosensitive stencil made from a light sensitive gelatin emulsion coated onto a polyester carrier or backing sheet which is exposed to a film positive and chemically processed into a stencil before adhering to the stretched screen fabric. After adhesion, the support or backing sheet is removed. This opens the portions of the stencil which are to print.

INLINE

A conveyorized system for transporting a product through a series of automated machines or printing presses.

IN-LINE PRESS

A non-perfecting press with one or more printing units, each consisting of an inking system, an dampening system, a plate cylinder, a blanket cylinder, and an impression cylinder.

KNIFE-CUT FILMS

A lacquer or similar film temporarily affixed to a clear support sheet, into which designs or images may be cut either mechanically or manually with a sharp knife, for making a screen printing stencil or a detailed photographic mask or positive from which a photographic stencil can be made.

KNIFE-CUT POSITIVE

A design or image cut into masking film which is usable in the same way as a film positive made by camera, for making a screen printing photostencil.

LAPPING COLORS

The imprinting of the edges or other portions of the area of a printed color by a succeeding color.

LAP REGISTER

See Lapping Colors.

LAPS

Non-printed or blank space on edges of printed poster paper used for joining and matching when multiple sheets are pasted on billboards.

LAYOUT

1. The drawing or sketch of a proposed printed image area; 2. The plan view of a printing plant or manufacturing area.

LETTERPRESS PRINTING

A process in which ink is applied to paper or other substrate by means of raised portions of printing plates or type. A variant of the process is rotary letterpress printing.

LINE COPY

See Line Drawing.

LINE COUNT

The number of lines of halftone dots per linear inch.

LINE DRAWING

Artwork, originals or printed matter consisting of lines or solids or dark and light tones. These can be reproduced by photographic printing screens or by hand-prepared screens, depending on the detail to be reproduced.

LINE IMAGE

A photographic image that is composed of fine, solid lines or dots or other shapes, all solid black or color, with no graduations of tones as in a continuous tone image.

LITHOGRAPHY

Alternative method of printing by the planographic process.

MAGENTA

A blue-red color, complimentary to green. One of the three primary colors; the other two are yellow and cyan.

MECHANICAL

Camera-ready art work.

MECHANICAL FLAT-BED PRESS

See Flat-Bed Press.

MECHANICAL HYSTERESIS

The difference of the indication with increasing and decreasing strain loading, at identical strain values of the specimen.

MECHANICAL PROPERTIES

Of a plastic material, its elasticity or inelasticity.

MECHANICAL RESISTANCE OF INKS

The extent to which heavy bodied inks inhibit good printing, by resisting proper flow through the stencil with normal squeegee pressure.

MESH

The open space between the threads of a woven fabric; also, the threads collectively on the fabric itself.

MESH APERTURE

The space between the woven threads of screen printing fabric, through which the ink passes in printing.

MESH COUNTER

A magnifier with a 1/4 inch square opening, by means of which the number of threads per linear inch of a screen printing fabric may be determined. Also called a Linen Tester.

MESH MARKS

1. A fine, cross-hatch pattern left by the mesh of the screen printing fabric, due to printing with an ink that does not have sufficient flowout, after the ink film has been dried; 2. A condition occurring when certain areas of the screen do not properly separate from the substrate, due to poor tensioning of the fabric or insufficient off-contact distance. See Screen Marks.

MESH NUMBER (Mesh Count)

The number of openings per linear inch in any given screen printing fabric; the higher the mesh number or mesh count, the finer the weave.

MESH OPENING

A measure of the distance across the space between two parallel threads, expressed in microns.

MESH OPENING AREA

See Aperture Percentage.

MESH VOLUME

The result of the mesh aperture’s width and length multiplied, which is then multiplied by the total thickness of the fabric, without consideration of stencil thickness.

MONOFIL

Short for monofilament.

MONOFILAMENT

A strand composed of a single thread or filament, usually produced by extrusion.

MONOFILAMENT POLYESTER

Screen printing fabric woven from single strands of extruded polyester plastic.

MONOFILAMENT POLYESTER SCREENS

Printings screens made with monofilament polyester screen printing fabric.

MULTIFIL

Short for multifilament.

MULTIFILAMENT

A term used to describe a yarn or thread composed of a number of filaments or fibers twisted together.

NEGATIVE

A photographic image on film in which the dark and light areas are reversed with reference to the original. Example -black copy on white card. When photographed, the copy portion of the negative would be clear and the background black. The negative is used to make a film positive with light and dark areas in correct relationship and the positive is used to make the stencil for screen printing.

NEGATIVE HOLDER

A device designed to hold the negative in proper position in an enlarger.

NEGATIVE OPAQUE

Available in either red or black in brushing consistency, negative opaque is used to repair pinholes or other blemishes on negatives which may occur in processing, or mechanical damage which may occur through careless or improper handling afterward.

NEGATIVE PLANE

The plane within a camera that is occupied by the film when ready to expose after proper focusing and removal of the ground glass.

NONIMPACT PRINTER

A printing device that creates letters or images on a substrate without striking it. Photocopiers, laser printers, and ink jet printers are some examples.

OFFSET

1. An indirect form of printing; 2. The transfer of a freshly screen printed image to the bottom of the printing screen, the back of a succeeding print, or other undesired surface.

OFFSET BLANKET

A fabric coated with synthetic rubber that transfers the image from the printing plate to the substrate. It is carried by the blanket cylinder.

OFFSET PAPER

A grade of paper manufactured in a range of weights in white or light colors used in screen printing and in offset printing.

OFFSET PRESS

A printing press designed for offset lithographic printing.

OFFSET PRINTING

A method of printing in which the design is printed on the surface of a temporary carrier before transfer to the substrate. The carrier with the design is placed in contact with the substrate to transfer the design to its final position.

OPACIFIER

An additive that renders a transparent or translucent ink incapable of transmitting light.

OPACIMETER

Instrument used to measure printing opacity and/or TAPPI opacity, of paper by measuring light transmittance.

OPACITY

A state in which a printed film or a substrate does not permit the passage of light. The opposite of transparency as a characteristic.

OPAQUE

1. Not able to transmit light; not transparent and not translucent; 2. (v) To apply an opaquing fluid to a negative.

OPAQUE EDGE (Safe Edge)

The edge of a sheet of photoscreen stencil film which has been covered with opaque tape or other opaque instrument during exposure which develops and washes out with the design portions of the stencil, thus providing a narrow space for handling of the sheet in order to minimize handling damage.

OPAQUE INK

Those screen printing inks which completely obscure the substrate or design previously applied on it in the printed area.

OPAQUE VINYL

The opposite of clear vinyl. The materials can be so pigmented that no light will pass through them. Between glass-clear and opaque formulations, there is a complete range of translucencies.

OPAQUING

Making portions of positive or negatives light proof so that no light will pass through the portion; blocking out or stopping up pinholes in negatives and positives before exposing.

PASTE INKS

Inks that are nonfluid. Lithographic, letterpress, screen printing, and some news inks are paste inks.

PHOTO OPAQUE
A liquid material used to block out unwanted portions of film positives or negatives and in producing handmade positives.

PHOTODIRECT PLATES
A type of lithographic plate that can be produced directly in either camera or projection types of equipment. The intermediate step of making a photographic negative or positive has been eliminated.

PHOTOPOLYMER
A type of polymer that undergoes a distinct change such as depolymerization, on exposure to light. When used as a photostencil material, requires no addition of photosensitizer.

PHOTOSTENCIL

Any light sensitive system which utilizes original or photo-generated artwork to produce a stencil. A thin layer of photosensitive gelatin
material, precoated onto a support or backing sheet of clear film, is one common type of photostencil.

PHOTOTYPE
Typeset copy prepared by photographic means.

PHOTOTYPESETTING
Act of preparing type material by photographic means to provide a positive film with the type matter in predetermined arrangement to form a line or lines.

PIGMENT
Substances that impart color, including black and white. Finely divided solid, organic or inorganic coloring material insoluble in the medium in which it is applied. Pigments must be bound to the receptor surface by dispersing in a vehicle or binder, such as resins in screen printing inks.

PIGMENT DYES
Textile dyes formulated from appropriate vehicles and pigments of mineral or synthetic origin.

PIGMENT EMULSIONS
Emulsion type screen printing inks which contain pigments for coloring effects.

PIGMENT VOLUME
The percentage by volume of a pigment in the nonvolatile portion of an ink, calculated from bulking value and other data.

PLATE
1. In screen printing, the term indicates the printing screen made ready for printing; 2. In other printing methods, the sheet on which the desired copy or design has been etched or molded to carry printing ink on its highest areas to the substrate.

PLATED-THROUGH HOLES
The result of a plating technique in electronic circuitry in which the holes drilled in the substrate for attaching wire lead components are plated with metal for the entire depth of the holes as they extend through the thickness of the substrate.

PLATE MAKER (Plate Printer)
An illuminated vacuum table for exposing photographic camera films for contact printing, or producing screen printing stencil films, litho plates, etc.

PLATEN
1. The flat portion of a die stamping machine that supports the dies; 2. A fixture on a T-shirt printing device that supports the item to be printed; 3. Another term for Printing Base.

PLATEN DRYER
A single panel flash curing unit generally used for wet-on-wet garment printing.

POLYMER
A compound formed by the reaction of simple molecules called monomers, having functional groups that permit their combination to proceed to high molecular weights under suitable conditions. A long-chain molecular structure.

POLYVINYL ACETATE
A vinyl polymer or copolymer used in making adhesives, coatings, and sheets.

POLYVINYL ALCOHOL (PVA)
A water soluble synthetic resin made by the hydrolysis of polyvinyl acetate. This resin has numerous uses as an emulsifying agent, binder for pigmented coatings, etc.

POSITIVE
Film or paper print from a negative in which light and dark areas are in correct relationship. A true picture. The photo-graphic image on film which corresponds to the original copy. The reverse of a negative.

PRE-PRESS
Refers to all preparatory operations performed before the actual printing operation.

PRESENSITIZED PLATE
A sheet of metal or paper supplied to the user with the light-sensitive material already coated on the surface and ready for exposure to a negative or positive.

PRESS RUN
The total number of copies printed. In fine art, this is called an “edition.”

PRESSURE CONTACT FRAME
A frame for holding two or more sheets face-to- face, or face-to-back, in-contact while exposing, the contact being forced by spring pressure from the back of the frame.

PRINT
(n) The final form of the screen printed image; (v) The act of printing.

PRINTABILITY
1. A collective term used to describe the properties of all components in a printing process; 2. That property of a substrate which yields prints of good quality; judged by uniformity of color of the printed areas, uniformity of ink transfer, contrast between the printed and unprinted areas, and rate of ink setting and drying.

PRINT CLOTH
Plain woven fabric, not napped, weighing not more than six ounces per square yard.

PRINTING AREA
The area under the printing screen and on the printing base in which a substrate is placed manually or automatically, to be printed. Not to be confused with Image Area.

PRINTING BASE
The flat support on which the substrate is placed for printing. It may or may not be equipped with vacuum arrangement to hold thin substrates in printing position. Also called Printing Table, Printing Bed.

PRINTING CYLINDER
The printing base on a cylinder press, which itself is a vacuum cylinder, of stainless steel or aluminum.

PRINTING INK
Any fluid or viscous composition used in screen printing, impressing, or transferring onto a substrate.

PRINTING LAMP
Generally, a carbon arc lamp used in illuminating or in exposing screen printing films and other sensitized surfaces.

PRINTING PASTES
A term used to indicate formulations of screen printing inks for either textile printing or ceramic and glass decoration.

PRINTING PRESS
A mechanical device to enable the application of ink to a substrate to reproduce a pattern or design.

PRINTING RUN
The total number of prints, plus overruns, to be made or which have been made.

PRINTINGS
The number of colors on an outdoor poster, multiplied by the number of sheets upon which each color is printed.

PRINTING SCREEN
The assembly of frame, fabric and stencil by which screen printing can be done. Sometimes called a plate, which is technically incorrect within the context of the printing industry.

PRINTING SECTION
That portion of a web screen printing press located after the in-feed, where one or more printing stations are provided, it is followed by drying, then die cutting and/or rewind stations, usually.

PRINTING STOCK
Substrates to be printed.

PRINTING STROKE
The movement of the squeegee across the printing screen which has the function of forcing the ink through the stencil and screen to form the imprint.

PRINTING TABLE
See Printing Base.

PRINTING UNIT
The sections on printing presses that house the components for reproducing an image on the substrate. In lithography, a printing unit includes the inking and dampening systems and the plate, blanket, and impression cylinders.

PRINTOUT
Information which has been written by automatic printer from a tabulator or computer.

PRINT QUALITY
That property which yields printed matter of good quality. it is judged by uniformity of ink transfer, contrast between the printed and unprinted areas, legibility of the printed matter, and rate of ink setting and drying, among other factors.

PRINT SHOULDER
The vertical borderline between the printing, or open sections and the nonprinting, or closed sections of the screen stencil.

PROCESS BLUE
See Cyan.

PROCESS CAMERA
Generally, a camera designed for accurate photographing of line, solid, halftone, colored copy and of objects to be reproduced by means of screen printing and other printing methods. Configuration may be vertical or horizontal. See Gallery Camera, Darkroom Camera.

PROCESS COLORS (Process Inks)
Inks of semi-transparent nature specifically formulated for four color process screen printing. The standard colors are magenta, yellow, cyan and black.

PROCESS CONTROL
Procedure for evaluating future performance through the use of statistical quality control methods.

PROCESSING
Chemically treating photographic papers, films, and plates after exposure.

PROCESS INKS
Those transparent inks which make up the means for multiple color process printing, generally magenta, cyan, yellow and black in color.

PROCESS LENS
A lens having a long focal length, corrected for flat copy and used in process cameras, or made with pantographs, dividers and other such devices.

PROCESS PRINTING
The printing from a series of two or more halftone screens to produce intermediate colors and shades. Usually in four color process – yellow, magenta, cyan and black.

PROCESS RED
See Magenta.

PROCESS TEMPERATURE
The temperature of the process medium, as recorded by a sensor.

PROCESS WASTEWATER
Any used water which results from or has had contact with the manufacturing process, or for which there is a reasonable possibility of contamination from raw material, intermediate product, final product, storage transportation, handling, processing or cleaning.

PROOF
A print made for trial purposes to check details of the design prior to the production run. It can be taken at one or more stages of the printing process.

PROOFING
Producing simulated versions of the final reproduction from films and dyes or digitized data (prepress proofing) or producing trial images directly from the plate (press proofing).

PVA
An abbreviation for polyvinyl acetate/alcohol solution used in direct-emulsion stencils.

PVAc
Abbreviation for Polyvinyl Acetate Emulsion.

PVC
Abbreviation for polyvinyl chloride, a plastic used in the manufacture of some screen printing materials. Plasticized PVC is generally known as “flexible vinyl”

REGISTER
Means of printing a composition of more than one color (or application), in order that the second and all succeeding colors are printed in the desired location in the reproductions with each color in exact alignment with all others. Register exactness required may be absolute or relative.

REGISTER DEVICE
A mechanical device for moving a printing screen toward either side, the top or the bottom, or rotating it to obtain proper location of the design with regard to the substrate.

REGISTERED NUMBERS
Heat-applied numbers that are centered on a sheet of paper with precision, guaranteeing correct spacing.

REGISTER GUIDES (Guides)
Physical stops, usually three in number, and so placed on the printing base in relation to two adjacent edges of the printing sheet to ensure proper positioning for printing where the two edges of the substrate come into contact.

REGISTER LOCKING SYSTEMS
A mechanical system by which a printing screen and its printing base can be locked into position after adjustments necessary to accomplish register have been made.

REGISTER MARKS
Crosses or other image devices applied to original copy prior to photography. Used for positioning negatives in perfect register or for color register of two or more colors in printing.

REGISTRATION
See Register.

RESIN
A solid or semi-solid material of vegetable origin, to obtained synthetically by solvent extraction, which can be dissolved to a liquid state, suspended in a vehicle to make an ink or coating, and which, on drying, forms the solid part of the dried, printed film. Resins tend to flow under stress and have no fixed melting point.

RESIST
A material such as an ink compound, coating, film or stencil used to protect the desired portions of a circuit board during etching, soldering or plating processing.

RESOLUTION
The relative ability of a stencil to form line pairs of acceptable acutance, at a minimum separating distance. Expressed in line pairs per inch.

ROLL-TO-ROLL
See Web Fed.

ROTARY LOAD
Refers to one design of garment printing devices whereby the loading pallets/platens rotate around a central shaft.

ROTARY SCREEN PRINTING
The screen printing of web or sheet materials using a semi-rigid cylindrical metal screen, which revolves on its axis and includes a squeegee blade mounted within the screen. Ink is pumped into the rotating cylinder during printing.

ROTATIONAL REGISTER
The accomplishment of register of a work piece by rotating either the printing screen or the printing base on its center.

ROTATIONAL VISCOMETRY
Method for measuring the viscosity of a material by sensing the torque required to rotate an immersed spindle at constant speed. The torque is proportional to the viscous drag on the spindle, thus to the fluid viscosity.

ROTOGRAVURE PRINTING
The process of printing with a thin, quick drying ink from a cylindrical surface having a etched design recessed into the plate surface.

SATURATION
1. The degree of intensity of a color; 2. The greatest degree of vapor that ambient air can hold at a certain temperature; 3. The greatest degree of concentration of a solute in a solution or solvent.

SCANNER
An electromechanical device that converts an image such as artwork or a photograph, into its electronic equivalent for subsequent computer storage, manipulation, and output.

SCREEN
1. (Printing screen) an assembly of stretched screen printing fabric on a frame with stencil attached, ready for printing; 2. (Halftone Screen) a transparent glass sheet marked with cross-hatched design to be placed before the camera film when photographing continuous tone art to produce dot structure of the design in the negative. Another type is produced photographically on film with vignette dots. The latter is placed in contact with the negative film.

SCREENABILITY
A characteristic describing how difficult or easy it is to print a material such as an ink, paste or coating through the screen.

SCREEN ANGLES
The angles at which screens for use in printing halftones must be placed with respect to the patterns of halftone dots to avoid moiré effects; theoretically 45°, 75° and 105° from vertical, these angles often vary in practical use.

SCREEN CARRIAGE
An arrangement of hinges, pivots, or other mechanical means of allowing limited and predetermined movement, to which the printing screen is attached for printing.

SCREEN CUTTING
1. Incorrect term sometimes used to denote manual cutting of knife-cut stencil film; 2. In glass decorating, it applies to the cutting from the underside of the fabric and/or stencil by the sharp edges of a preprinted color to the edge of a flat substrate such as a tile; 3. In circuit printing it applies to the wear and/or cutting of the screen by rough substrate edges.

SCREEN DEPARTMENT
The area, usually enclosed, in a screen printing plant used only for the making of printing screens.

SCREEN DISTANCE
The distance a halftone screen is set in front of the ground glass in a process camera to bring the dot structure into proper focus.

SCREEN FABRIC
Woven fabrics for screen printing made of silk, synthetic polyester or nylon fibers, or finely drawn wire, the latter usually stainless steel.

SCREEN HOLDERS
The fittings or clamps by which printing screen frames are attached on a screen printing press or manual screen printing unit. See Screen Carriage.

SCREEN OPENER
A chemical, usually in aerosol spray form, used to open dried-in areas of the screen stencil.

SCREENING
1. A short, commonly used term to indicate screen printing – the act, not the result; 2. The conversion of continuous tone copy to halftone.

SCREENING IN CONTINUOUS TONE
Screen printing with several colors of ink, or inks of several densities of hue, which have been mechanically blended on the printing screen so that one will blend smoothly without demarcation line into the next. This produces evenly graduated tones without the use of halftone screens.

SCREEN INK
I
nk, usually quick drying, full bodied and formulated for screen printing. There are a tremendous variety of screen inks made or adjusted for adhesion to variety of substrates.

SCREEN MARKS (Mesh Marks)
Marks left by the fabric in the surface of the screen printed imprint, due to lack of flow capability in the ink or color, or to insufficient snap-off.

SCREEN MESH
1. A term generally indicating screen printing fabric; 2. That portion of the screen printing fabric which can be counted or measured to identify fineness or coarseness of the fabric.

SCREEN PRINTING
A commercial and industrial printing technique which involves the passage of a printing medium, such as ink, through a taut fabric to which a refined form of stencil has been applied. The stencil openings determine the form and dimensions of the imprint thus produced.

SCREEN PRINTING PLATE (Printing Screen)
A frame or supporting device onto which is stretched a fabric having open spaces in the areas of the fabric representing a design to be printed. Ink, dye, or other viscous liquids are forced through the open spaces onto the substrate.

SCREEN PROPER
The stencil portion of a printing screen.

SCREEN RANGE
The density range that a halftone screen can produce.

SCREEN RULING
The number of lines or dots per linear inch in a halftone screen.

SCREEN SEEPAGE
A seepage of ink through open parts of the stencil which may occur when stopping the printing action for an unduly long period when the stencil has excess ink on the upper surface.

SCREEN STABILITY (Ink Stability)
The ability of an ink to print for a prolonged period through all open areas of the stencil, without drying-in.

SCREEN TINT
A halftone that has dots of uniform size and density across its surface; e.g., a 20% screen.

SCREEN VALUE
The number of lines per square inch on any halftone, tint or four-color separation. The higher the screen value, the finer the screen and the more detail will be reproduced. Because the dots in finer screens are so close together, ink can “trap” or collect around the dots and muddy the fine detail, especially if printed on lesser grades of paper.

SCREEN WASHER
A unit in which printing screens can be washed out to remove ink residues after printing, or be reclaimed completely by removing the stencil, usually by high pressure spray. Automatic units are also manufactured.

SCREEN WORKING TEMPERATURE
The temperature at which a heated printing screen is maintained while printing thermoplastic inks.

SHEET
Any thin stock with two faces or planes that are greater in measure than the thickness.

SHEETER
1. A device on a printing press to convert continuous lengths into smaller sheet units; 2. A device, separate from the press used for cutting cloth or paper web materials into sheets.

SHEET FED
In relation to a machine feeding system, the term refers to pick-up and placement of separate sheets of substrate at predetermined intervals.

SHEETING
The reduction of stock in continuous rolls to individual sheets of required length.

SHEET MATCHING
A term used to describe an accurate line-up from sheet to sheet, both vertically and horizontally, when either printing or posting an outdoor poster, includes consistency of printed color from sheet to sheet also.

SHELLAC
An alcohol-soluble natural resin.

SHORTENING COMPOUNDS
Ink additives that shorten an ink and reduce its tendency to fly or mist.

SLIP COMPOUND
An ink additive that improves the scuff resistance of a printed ink film.

SOLVENT
A dissolving, thinning or reducing agent. An additive used to reduce viscosity of a screen printing ink, generally. Specifically, a solvent is a liquid that dissolves another substance, such as a resin.

SOLVENT ATTACK
The effect or change in a material on coming in contact with a solvent. Solvent-based inks may be attacked by the proper solvent, even when dried.

SOLVENT DISPERSIONS
Inks in which pigments are dispersed in a solvent solution containing a solvent-soluble binding agent. These inks (or dyes) do not require steaming or heat curing.

SOLVENT-EVAPORATING INKS
Inks which may be dried after printing by allowing the solvents to vaporize either in ambient or elevated temperature conditions.

SOLVENT EVAPORATION
Vaporizing of liquid solvents, resulting in their removal from a printed film, hence drying of the ink film.

SOLVENT POWER
The dissolving power of a solvent. See Solvent Strength

SOLVENT REACTIVATION
See Solvent Rewettable.

SOLVENT RELEASE
Refers to the ability of a binder to influence the rate of evaporation of a solvent.

SOLVENT RESISTANCE
The resistance of a printed area and/or the substrate to the dissolving action of specified organic liquids.

SOLVENT REWETTABLE

1. A term indicating a dry ink imprint that can be changed back to the wet state by introduction of a solvent; 2. A dry film that can be rewetted and removed by saturating with solvent.

SOLVENT STRENGTH
The ability of a solvent to dissolve materials. A strong solvent will dissolve many materials, a weak solvent will dissolve few materials.

SPLICE
A method of joining paper or plastic webs within a pressure sensitive roll or within a plain paper roll to produce a continuous, operational web.

SPREAD
A camera process whereby images are made thicker without changing their general shape or positioning.

SQUEEGEE
A tool used to force ink through the openings of a screen printing stencil when in contact with a substrate, consisting of a rubber or plastic strip or blade held in the edge of a wooden or metallic handle. A variety of blade shapes and hardness are available.

SQUEEGEE ANGLE
The angle formed by the near-vertical axis of the squeegees and the plane of the screen, measured when the squeegee is in position, but no force or movement has been applied. See also Angle of Attack.

SQUEEGEE BRIGHT GOLD
A special preparation of gold for screen printing on glass or ceramic ware.

SQUEEGEE CARRIAGE
A system that holds the squeegee at the proper angle for printing. This is especially useful with very large screens.

SQUEEGEE HOLDER
That part of a screen printing press or manual screen printing unit to which the squeegee is attached for printing.

SQUEEGEE OIL
A mixing medium in liquid form of organic composition used as a vehicle in screen printing colors for glass.

SQUEEGEE PASTE (Screening Ink)(Screening Paste)
A mixture of squeegee oil and inorganic materials compounded for screen printing on glass.

SQUEEGEE PRESSURE
The force exerted by the squeegee on the printing screen to bring it into contact with the substrate and press ink through the open screen apertures.

SQUEEGEE PRINTING EDGE
That corner or edge of the squeegee blade that contacts the fabric to force the ink through the stencil.

SQUEEGEE PROFILE
The cross-sectional shape of the squeegee blade; e.g., rounded, square-edged, etc.

SQUEEGEE SHARPENER
A mechanical device usually in the form of an abrasive roller, belt or wheel, to restore sharpness to squeegee edges.

STACK PRESS
A flexo press that has all of its individual color stations vertically stacked on over another.

STENCIL
The component of a printing screen which controls the design to be printed.

STENCIL DESIGN AREA
That portion of a screen printing stencil which includes only the predetermined design to be printed.

STENCIL KNIFE
A tool for cutting screen printing stencil film usually with a small diameter, round handle to facilitate “twirling” in the fingers to trace very small curves, and with a blade about 1/8″ wide, sharpened to a bevel to form a cutting point, usually beveled on both sides of the blade.

STENCIL MEDIUM
Any film or emulsion material or sheet material of any kind from which a screen printing stencil can be made.

STENCIL SILK
S fabric made from multifilament strands of silk suitable for making printing screens.

STENCIL THICKNESS
The actual thickness of the stencil portion of a printing screen measured in mils.

STENCIL VOLUME
The total volume of a single imprint segment represented by the width of aperture times length times total depth of fabric and stencil.

STEP AND REPEAT
A technique of repeating a single image exposure onto photosensitive material through a negative or positive as may be required, in accurately arranged and spaced increments, to obtain multiple exposures of the same design on a single sheet of film.

STRIPPING
1. Removing unwanted film from the support in knife-cutting stencils; 2. Removing waste material after die cutting; 3. Removing stencil and ink from screen fabric in reclaiming printing screens; 4. Taping various parts of photographic positives or negatives together into desired relationship on a flat prior to preparing a stencil; may also include hand-out components.

STRIPPING FILM
1. Photographic film in which the emulsion, after processing, can be relocated onto another support; 2. Knife-cutting film with the same capability as photographic stripping film.

SUBSTRATE
A term meaning, generally, a surface to which something adheres, the base material to be printed on, or the surface to which a pressure sensitive decal is adhered. In particular, any surface on which screen printing is applied.

SURFACE PLATE
A lithographic plate in which the light-sensitive coating becomes the printing image. Surface plates can be either presensitized or wipe on.

SURFACE STRENGTH
The ability of a paper to resist a perpendicularly applied force, such as that in the splitting of an ink film, to its surface before picking or rupturing occurs.

TACK (Grab)(Quick Adhesion)(Quick Stick)(Touch-Tack)1. Surface “stickiness” to touch, as in pressure sensitive adhesives designed to adhere on contact, in other adhesives in various stages of drying, and in flock adhesives to which flock is to be applied. A state of ability to adhere; 2. The relatively low splitting force of ink.

TACK-FREE FINISH
Any coating or ink that is not sticky to touch after curing or drying.

TACKIFIER
An additive used to improve stickiness of an adhesive film.

TACKMETER
Instrument used to measure the tackiness of materials by pressing two surfaces together under a known weight for a given time period, and then using a steadily increasing force to separate them.

TACK RAG
A treated cloth used to remove dust or other foreign material from the surface of the substrate, stencil or photofilm (particularly plastics) prior to use in printing.

TACK SURFACE
A surface having a sticky feel on touching, such as pressure sensitive adhesive ink that may not be completely dry, etc.

TRAP, or LAP REGISTER
The overlapping of a narrow strip–the lap–of one color over another at their juncture to make it easier to fit the colors together on the press.

TRAPPING OF INKS
The property of a printing ink that makes it possible to superimpose one color on another, both in wet and dry printing; may be used to obtain a third color which is a combination of the two applied, or to hide the first by overprinting the second with an opaque color.

TUSCHE
A black or very dark gray waxy substance which repels water. Available in liquid or solid crayon form, it is used to manually draw design on the screen printing fabric to make a printing screen.

TUSCHE-GLUE PRINTING SCREEN
A printing screen made manually by drawing desired design on the mounted, properly stretched screen printing fabric with tusche, squeegeeing a coating of water soluble glue on one side, then dissolving the tusche with mineral spirits. The tusche having been placed where the stencil is to print; when washed out leaves the open stencil design.

ULTRAVIOLET CURING
Polymerization effected by the presence of ultraviolet rays.

ULTRAVIOLET DRYING SYSTEM
Any system which utilizes ultraviolet rays to effect the drying or curing process of inks, coatings or adhesives. More correct term is Ultraviolet Curing System.

ULTRAVIOLET LIGHT
Highly energetic part of the electromagnetic spectrum of rays falling between 200 and 400 nanometer wavelengths, which are shorter than that of visible light. Carbon arc lamps, black light and mercury vapor lamps are examples of artificial sources of ultraviolet light used by the screen printer.

ULTRAVIOLET STABILIZER
A chemical compound which when mixed with a thermoplastic resin, selectively absorbs ultraviolet rays.

UNWIND SECTION
The first section of flexographic and rotogravure presses.

UV
Abbreviation for Ultraviolet Light.

UV INK
Refers to screen printable inks which are chemically formulated to polymerize under exposure to intense ultraviolet light.

VARNISH
A solution or suspension of resins in a liquid vehicle capable of forming a decorative and/or protective coating as the vehicle dries by oxidation.

VARNISHING
A process whereby a sheet, usually printed or unprinted paper, paperboard or similar substrate is coated with a film forming liquid.

VARNISHING MACHINE
A machine used for varnishing paper cardboard or similar stock.

VARNISH-ON DECAL
A decal designed to be applied to a surface by means of a coating of varnish applied at the time just preceding placement of the decal.

VEHICLE
The fluid portion of screen printing ink which acts as a carrier for the pigment.

VISCOMETER
An instrument for measuring the viscosity of liquids at specified temperature and atmospheric conditions, by measuring the force required to move one layer over another without turbulence.

VISCOSITY
A term used to designate the degree of fluidity, or internal resistance to flow, of a compound ranging between liquid and heavy paste conditions.

VISCOSITY COEFFICIENT
The constant of proportionality of the viscous force to the velocity gradient between two parallel Newtonian fluid layers.

VISCOUS
Description of a material that is thick, resistant to flow and having a high viscosity.

VM & P
A naphtha of high flash point solvent employed in the manufacture of some inks. The initials by which it is called are for Varnish Maker’s and Painter’s naphtha.

V.O.C.
Abbreviation for Volatile Organic Compound, which refers generally to organic solvents.

VOLATILE
Subject to evaporation at a relatively low temperature.

VOLATILE ORGANIC SOLVENTS
Liquid solvents that tend to vaporize at room temperature; high concentrations can be injurious to health.

WEB
A continuous sheet of pliable manufactured material; may be paper, cloth, film, etc.

WEB CONTROL
Means of moving a continuous length of substrate, such as textile material, through the printing processes in a manner which prevents its creeping sidewise.

WEB FED
1. An automatic feeding system that feeds substrates from a continuous roll, synchronized to a stop motion arrangement which stops movement for printing; 2. A term to indicate a type of screen printing press that feeds the substrate from a bulk roll or bolt (as in textiles).

WEB GUIDE
Device which keeps the web traveling straight through the press.

WEB LEAD
A continuous strip of paper extending from the supply roll, over rollers, and through printing units to start the web feed.

WEB TEMPERATURE
The temperature of the web in the drying oven as opposed to the temperature of the oven interior.

WEB TENSION
The controlled tension of the web material during transport through the press and other inline operations.

WEB WIDTH
The maximum width available of a given film deter-mined at the manufacturing point.

WETTING UP
The process of placing ink in the printing screen and making one or more printing strokes with the squeegee to distribute the ink evenly before beginning the actual production run.

WET WEB TESTER
Instrument used to predict wet and dry sheet strengths of paper.

WETTING AGENT
A chemical additive which reduces the surface tension of a fluid, inducing it to spread readily on a surface to which it is applied, thus causing even “wetting” of the surface with the fluids.

WET-ON-WET
Describes the printing of multiple colors onto a substrate before the previously printed colors have dried, used in the screen printing of absorbent substrates, such as textiles.

WIPE-ON PLATE
Lithographic plate on which a light-sensitive coating is wiped on, or applied manually or by machine.

WORN-AND-TUMBLE
A printing imposition where a single printing plate contains all of the pages or images to be printed on both sides of the press sheet with a single color of ink. The first side of the sheet is printed, the sheet is flopped end for end, the second side is printed, and then the sheet is cut in half (parallel to its ends) to yield two identical units.

WORK-AND-TURN
A printing imposition where a single printing plate contains all of the pages or images to be printed on both sides of the press sheet with a single color of ink. The fist side of the sheet is printed, the sheet is turned over sideways from left to tight, the second side is printed, and then the sheet is cut in half (parallel to the sides) to yield two identical sides.

XEROGRAPHY
An electrostatic, nonimpact printing process in which heat fuses dry ink toner particles to electrically charges areas of the substrate, forming a permanent image. The charged areas of the substrate appear dark on the reproduction, while the uncharged areas remain white.