Printing Terms & Acronyms.

Glossary of PrintTerminology



Adhesive binding: (see also Perfect Binding & PUR Binding) Type of thread-less binding in which the leaves of a book are held together at the binding edge by glue or synthetic adhesive.

Against the Grain:
Folding at right angles to the grain direction of the paper being used, as opposed to with the grain. Also called across the grain and cross-grain. This can cause cracking on heavier papers unless the paper is scored or creased

Ascender:
In typesetting, the part of a lower case letter which rises above the main body, as in the letter "b"..

ASCII:
American Standard Code for Information Interchange. This is a standard coding system within the computer industry to convert keyboard input into digital information.

Author’s Corrections: Corrections made by the author on proofs,that alter the original copy. Author’s corrections are chargeable at the discretion of the printer.

Back Up: Printing on the reverse side of a sheet already printed on one side. Back up position is critical and must be accurate to ensure consistent position throughout a folded product.

Bimetallic Plate: Plate in lithography used for long runs. The printing image base is usually copper and the non printing area is aluminium or stainless steel, giving a harder wearing plate than the conventional aluminium litho plate.

Bit: In computers, the basic unit of digital information. It is a contraction of BInary digiT (BIT).

Bit Map: In computer imaging, the electronic representation a page, indicating the position of every possible spot from 0 to 100 and rest from other document.

Black and White: Originals or reproductions in single colour, also known as monotone or mono.

Blade coated: Paper coated by a process in which the freshly applied wet coating is smoothed and the excess removed by a thin, flexible metal blade which bears on the coated surface.

Blanket: In offset printing, a rubber surfaced fabric that is clamped around a plate cylinder to transfer the image from the impression cylinder to the substrate.

Bleed: When the printed image extends beyond the trimmed area of a page, the image must be increased, usually by a minimum of 3mm. This extended area isknown as the bleed.

Blind Embossing: The process of stamping an image into the paper to produce a depressed effect on the paper surface, without the use of inks.

Blind Blocked: In binding, to impress or stamp a design upon the cover. The design can be blocked in coloured inks, or metal foil, including special effects such as holographic.

Bond Paper: A grade of writing or printing paper, usually used for letterheads or business forms.

BPOP: Abbreviation for “Bulk packed onto pallets”.

Broadsheet: Any sheet in its basic size (not folded or cut); also denotes a newspaperformat.

Bromide: A photographic paper used in phototypesetting on which a photographic image is created. Almost obsolete with the advent of digital artwork.

Bulk: Thickness of a sheet of paper or board. Also used to indicate the relativethickness of a sheet in relation to its weight. Usually measured in microns (1,000th of a millimetre) ot 1,000 of in inch.

Calendering: In papermaking, the smoothing action of chilled rollers on the paper surface.

Camera Ready: Artwork or copy ready for photographic reproduction.

Case: In bookbinding, the hard covers of a case bound book

Chalking: When the dry ink on a printed piece can be rubbed off. Happens when there is insufficient bond between the pigment and the vehicle.

Chill Marking: Marking caused by the chill rollers on a heatset web press, which cool the web after drying.

Chromolithography: Colour printing by means of lithography.

CMYK: 
Cyan, Magenta, Yellow, Key (black), being the primary colours used as the basis for 4-colour process printing. Also known as 4 colour process.

Coated Stock: Material coated on one or both sides with a mixture china clay, latex and other loadings to fill up surface pits and improve the printing surface. The process can be accomplished either on-line on the papermaking machine (machine coated) or as a separate operation (off-machine coated).

Cockling: Deformation of a sheet of paper due to unequal shrinkage giving it a slightly crumpled appearance. This can occur as part of the heatset web offset drying process, particularly on lightweight coated papers.

Coldset Web: A reel fed press with limited or no drying facility.
Only uncoated papers such as newsprint or bond can be printed on coldset webs.

Collotype Printing:  Printing from a bichromated gelatin surface, which has been rendered non-uniformly ink receptive by light transmitted through through an unscreened negative. Collotype was one of the first photomechanical printing processes to be developed.The main factor setting collotype apart from the majority of mainstream printing processes of the 20th century, was its ability to print continuous tone detailed images without the use of a halftone screen.

Colour Correction:  Alteration of the colour of a photographic image by electronic retouching.

Colour Proofing: This term describes a wide range of techniques which have been developed to reproduce full colour images from film or digital data available, prior to the actual print run; thus allowing the client, colour separation house and printer to view the “proofed” result, prior to the actual print run.

Colour Separation:  In photographic reproduction, the process of separating colour originals into the primary printing colour components.

Concertina Fold: Folding each panel of a leaflet in alternate directions, so that when opened out the finished product is folded in a zigzag fashion.

Contact Print: A photographic print made from a negative or positive in contact with sensitised paper, film or printing plate.

Continuous Tone: A photographic image with gradient tones from black to white.

Contrast: The tonal gradation between the highlights, middle tone and shadows in an original or reproduction.

Crease: An indented line pressed into the substrate to reduce resistance and allow folding without cracking or splitting.

Cromalin: A DuPont electrostatic colour proof. Conventional Cromalin proofing requiring film exposure is almost obsolete now and has been replaced by digital proofing, including the Digital Cromalin.

Crop: To cut a piece of copy or artwork to the size indicated on an original by cropmarks.

Crossover: When an image runs across two pages, requiring the image to be split where it crosses the spine.

CTP: Acronym for Computer To Plate, the process by which digital data is converted via a RIP device to drive a platesetter, which generates the finished printing plate.

Curl: In paper, the distortion of a sheet due to differences in structure or coatings from one side to the other or absorption of moisture on an offset press.

Cut-Off: In web offset printing, the cut length of a single revolution of the printing cylinder. Conventional long grain presses have a 620 to 630mm cut-off, whereas short grain presses typically have 560 to 600mm cut-off.

Deckle Edge: The untrimmed ragged edges of paper formed at the outer edge of a jumbo reel of paper on a papermaking machine.

Densitometer: A device for measuring the colour density at a specific location on film or printed product, either by reflected or transmitted light.

Descender: That part of a lower case letter which extends below the main body as in the letter g.

Die-Cutting: The process of using sharp steel blades known as rules to cut a shape into paper or board.

Die-stamping: An intaglio process of printing in which the resultant impressionstands out in relief above the surface of the stamped material, either coloured (using inks or foil) or blind (no inks or foils).

Digital Colour Proofs:  A colour proof produced from digitaldata. Digital proofs may be Pre-RIP (before rendering pixels), or Post-RIP. Low resolution proofs are generally used to check content only and High resolution to check colour matching.

Dithering: A technique of filling the gap between two pixels with another pixel having an average value of the two to smooth out the resulting image.

Dot: The individual element in both halftones and four colour process printing.

Dot Gain: In printing, a defect in which dots print larger than they should, causing darker tones and stronger colours.

Doubling: Printing defect appearing as blurring or shadowing the image. Doubling may be caused by problems with paper, cylinder alignment, blanket pressures or dirty cylinders.

Dots Per Inch: (dpi) A measure of resolution on the printed page.

Drawn-on Cover: A paper book cover, which is attached to the sewn book by gluing the spine.

Drop-Out: Fine halftone dots or fine lines which are eliminated from thehighlight areas of the plate during the platemaking process.

Duotone: A two-colour halftone reproduction from a one colour photograph.

Dummy: A sample of a proposed job made up with the actual materials and cut to the correct size to show bulk, style of binding etc. Also a complete layout of a job showing position of type matter and illustrations, margins etc.

Duplex Paper: A paper with a different colour or finish on either side of the sheet

Elliptical Dot: In halftone photography, elongated dots which give improved gradation of tones particularly in middle tones and vignettes.

Embossing: The process of impressing an image in relief into the paper to produce a raised effect on the paper surface, without the use of inks.

Emulsion Side: The side of the film coated with a light-sensitive emulsion.

EPS: Encapsulated Post Script, a computer file format usually used totransfer post script information from one program to another.

Filmsetter: An output device which produces film positives or negatives directly from Ripped data.

Fit: Printers’ terminology for the accurate positioning of all of the elements of one colour with all of the elements of another colour on a printed sheet. Sheets may "register" but not fit.

Flexography: A relief process in which printing is done from a rubber or plastic stereo (plate). Flexo presses can print on a wide variety of substrates including metal and plastic, but print quality is inferior to litho or gravure.

Flying Imprinter:  A device on a printing unit of a web press which allows for one plate to be changed without stopping the machine.

Folio: The page number.

Forme: In printing, one side of assembled pages or other images for printing. In die-cutting, the wooden board in which the cutting, creasing and perforating rules are mounted.

Four-colour Process:  Technique of printing that uses black,magenta, cyan and yellow to simulate full-colour images. Colours are reproduced by combinations of these four process colours. Also called process printing.

FPO: An acronym (For Position Only) used in mechanical presentation toidentify the crop specifications on a specific piece of composition.

Galley Proof: A proof of text before being made up into pages. Also known as a slip proof.

Ganging-up: Imposing different images on a sheet to save makereadies. Different ratios of images can be used to create different quantities; for instance a sheet 8 images can be printed 4: 3: 1, so each 1,000 printed sheets would contain 4,000 of image one, 3,000 of image two and 1,000 of image three.

Ghosting: (1) Phenomenon of a faint image appearing on a printed sheet where it was not intended to appear. Chemical ghosting refers to the transfer of the faint image from the front of one sheet to the back another sheet. Mechanical ghosting refers to the faint image appearing as a repeat of an image on the same side of the sheet. (2) Phenomenon of printed image appearing too light because of ink starvation.

Gilding: In book printing, the application of gold leaf to the edges of a book.

Grain:  In papermaking, the direction in which most of thefibres run. Tear any piece of paper and it will have one direction where it tears in a straight line (the grain direction) and one where the tear is more ragged (across the grain). Wetting a strip paper will cause it to curl in the opposite direction to the grain.

Gravure: Printing process in which recesses on a printing cylinder are filled with ink and the surplus removed by a doctor blade. The paper contacts the cylinder and ‘lifts’ the ink from the recesses, creating a much heavier ink film than lithography. High quality results can be achieved on low-grade papers due to the heavy inking creating a high gloss surface. Generally used for long-run printing because of the high cost of the cylinders.

Grey Balance: The combination of the four process colours which produce a neutral grey.

Grind-Off: The area which runs along the spine of each section (signature) of a perfect bound book which is removed after being gathered to allow the glue to penetrate every leaf. The UK standard grind-off dimension is 3mm.

GSM: Abbreviation of grams per square metre. Denotes the substance of paper or board – the higher the gsm, the heavier the substrate.

Gutter: The blank space or inner margin from printing area to binding.

Halftone: The reproduction of continuous-tone artwork into a series of dots.

Heatset Web: Reelfed press equipped with a drying tunnel which dries the ink before the printed web of paper is either folded, sheeted or re-reeled.

Hickeys: In offset lithography, spots or imperfection in the printing due to contamination on the press, such as paper particles, dried ink spots etc.

Impression: In printing, the pressure of the plate or blanket as it comes incontact with paper.

Imposition: Arrangement of pages in a sequence, which will read consecutively when the printed sheet is folded.

Intaglio: Printing method in which the image in the plate is etched or recessed. The ink is applied to the plate, wiped clean and then the ink remaining in the recesses transfers to the substrate.

Jog: To align sheets of paper into a pile prior to cutting.

Kerning: In typesetting, the spacing between two characters.

Keyline: An outline drawing on artwork to indicate the exact shape, position and size for such elements as halftones, line sketches, etc.

Kiss-Cut: Light cut into the peelable surface of a selfadhesive sheet, leaving the backing sheet intact.

Laid: Finish on bond or text paper on which grids of parallel lines simulate the surface of handmade paper. Laid lines are close together and run against the grain; chain lines are farther apart and run with the grain.

Lamination: A plastic film bonded by heat and pressure to a printed sheet. The laminate can be either gloss or matt to enhance the appearance of the print and provide moisture-resistant protection to the paper surface.

Landscape: Orientation of the sheet or end-product where the horizontal dimension is greater than the vertical.

Leading: In composition, the distance between lines of type, measured in points.

Letterpress: Method of printing from raised surfaces, either metal type or plates whose surfaces have been etched away from image areas. Also called block printing.

Limp Cover: A flexible book cover, as distinct from a cased-in board cover.

Line Copy: Copy suitable for reproduction without using a halftone screen.

Lithographic printing:  Method of printing using plates whose image areas attract ink and whose non-image areas repel ink. Non-image areas may be coated with water to repel the oily ink or may have a surface, such as silicon, that repels ink. The printing and non printing surfaces are on the same plane on the plate and the substrate makes contact with the whole surface.

Long grain press:  A press where the longest side of the standard folded product runs parallel to the grain of the paper.

Loose Insert: Any item inserted into a printed product without being affixed in any way. Can be either placed (in a specific position in the product) or random (anywhere in the product).

Make-Ready: In printing, all work done to set up a press for printing, beforeimpression count is activated and good copies are produced.

Mask: In colour separation photography, an intermediate photographic negative or positive used in colour correction.

Mechanical: A term for a camera-ready paste-up of artwork.

Machine finished(MF):  Any finish obtained on a papermakingmachine. It can refer to either the finish on the sheet as it leaves the last drying cylinder of the machine, or the finish given to a sheet by calendering online.

Mid Tones: The tonal range between highlights and shadows of a photograph orreproduction.

Moiré: Screen pattern caused by a clash of screen angles in litho reproduction.

Mottle: The bruised or spotted appearance of the printed image. There arenumerous possible causes of mottling including paper surface, ink/water balance, ink piling, cylinder marking and printing pressures.

Mylar: A stable polyester film used as a base for film mounting or a grid for mounting perforating and scoring rules.

Nipping: In the book binding process, a stage where air is expelled from it's contents at the sewing stage.

Offset: In printing, the process of using an intermediate blanket cylinder to transfer an image from the impression cylinder to the substrate.

Outsert: A printed element which is usually stitched to the outside of amagazine cover.

Overprinting: Printing onto a sheet which has been previously printed. Typically used to add dealer addresses to generic brochures.

Ozalid: In lithography, a photographic proof made from planned-up films used to proof check the position an image on the page and page imposition on the sheet. Also known as a Blue-line or Dyeline proof.

Pantone: The Pantone Matching System (PMS) is a colour standard which defines a wide range of colour solids and the combination of process colours required to achieve the closest match to the solid Pantone colour.

Part Mechanical: A paper containing up to 50% mechanical pulp, with the remainder being made up of chemical pulp.

Perfect Binding: A method of adhesive binding with a square-backed spine. Individual sections are collected together and the spine is ground off. Hot-melt glue is then applied to the spine and a cover drawn on before the product is trimmed flush to the final size.

Perfecting Press:  A printing press that prints both sidesof the sheet in one pass through the press.

Pica: A unit of measure in the printing industry. A pica is approximately 0.166 in. There are 12 points to a pica.

Pick-up Page: An exact repeat of a page used in a previous edition.

Piling: In printing, the build-up of ink on rollers, plates or blankets which cause an uneven, mottled appearance in the print.

Pin Marks: In web printing, the web of paper can be driven into the folder by pins which penetrate the surface the web on the outer edges of the sheet. The resulting holes are called pin marks. Pin marks are usually trimmed off but newspapers often have visible pin marks.

Pin Register: The use of datum points punched into copy, film and plates to ensure that the colour separation is accurate. Protocol and Billows are examples of different protocols used by printers.

Pixel: In electronic imaging, the basic unit of digital imaging.

Plate Cylinder: The cylinder of a press onto which the printing plate is mounted.

Platesetter: An output device which produces a finished printing plate directly from Ripped data. Also known as a CTP device.

Portrait: Orientation of a sheet or end-product where the vertical dimension is greater than the horizontal.

PostScript: A page description language (PDL) developed by
Adobe, which defines the contents and layout of a page in electronic form. PostScript is also programming language which is interpreted by a PostScript RIP in output devices such as filmsetters or platesetters (CTP) in order to reproduce the original page.

Pre-Press: The stage of the print production process which takes place afterdesign and before printing.

Primary Colours: Additive and subtractive primary colours can be mixed to form all other colours. The additive primary colours are red, green and blue (RGB) and can be added together to make all other colours, as is done when light is emitted from the screen of a television set or computer monitor. The subtractive primary colours (cyan, magenta and yellow) are those that, when mixed, subtract light from white to make all the other colours. This is what happens when pigments are mixed to create printing inks.

Process Printing:  Printing using the process colour set (CMYK).

Progressive Proofs(Progs):  Proofs which show the sequence ofprinting and the result after each additional colour has been applied.

Proof: A representation of the printed product which is checked prior to print production.

PUR Binding: The same process as perfect binding, but a synthetic adhesive(Polyurethane React) is used in place of conventional hot-melt glue. The glued spine is more pliable and the adhesive bond much stronger than a perfect bound product and so has increased longevity.

Quarter-fold: Two or more folds, each fold at 90 degrees to the previous one. Also called right-angle fold.

Ram Bundled: A method of packing printed products by strapping a bundle very tightly with end-boards to compress the product and keep it flat for subsequent machine insertion.

Ream: Five hundred sheets of paper.

Reel: Term used for continuous roll or web of printing paper.

Reel Width: The dimension of a reel of paper measured across the reel (against the grain).

Register: Adjustment of colour plates to obtain perfect super imposition of colours.

Register Marks: Cross-hair lines on mechanicals, films and plates used for positioning pages or images to enable accurate register on press.

Relative Humidity(RH):  Quotient of the amount of moisture in airand the amount that would saturate it at the same temperature andpressure, expressed as a percentage.

RGB: Red, green, blue additive primary colours. RGB files must be converted to CMYK at the pre-press stage prior to printing 4 colour process.

RIP: Acronym for Raster Image Processor, which generates a bitmap to send to the printing device (filmsetter, platesetter or digital press). The input data is either a file written in a page description language such as PDF or another bitmap. In the latter case, the RIP applies either smoothing or interpolation algorithms to the input bitmap to generate the output bitmap.

Rotary Trimmed: In-line trimming of a product as it passes over slitting knives. Very cost effective, but can leave a “feathered” edge,not as clean-cut as a static knife trim on a finishing line.

Run-Around: In composition, type set to fit around a picture or other designelement.

Saddle-stitch: Method of binding where folded sections are inset and secured together with wire staples (also known as wire-stitch).

Safelight: Lamp used for illumination of a darkroom without affecting light-sensitive materials.

Scanner: An electronic device used to convert a continuous tone original into a series of halftone dots for printing.

Score: To impress or indent a mark with a string or rule in the paper, to make folding easier.

Scum: Traces of printing ink which temporarily adhere, during litho printing, to the non-image area of the plate due to its inability to repel ink.

Selective Binding:  Recent developments in binding technology allow specific sections to be included or excluded from a single copy within a print run dependant upon electronic information linked to the address file the recipient. This is known as selective binding.

Serif:  The short cross-strokes at the ends of the main strokes of letters in some typefaces. Fonts with these cross-strokes are known as serif faces and those without are known as sans serif.

Set Off: 
Transfer of ink from one printed sheet to another.

Short grain press: 
A press where the shortest side of the finished product runs parallel to the grain of the paper.

Show through: The degree to which a printed image is visible through the paper due to the lack of opacity of the paper.

Sidelay: The datum point on the press, at 90 degrees to the grip edge, which controls the lateral position of the sheet. The same sidelay must then be used when trimming the sheet to ensure that the image position remains constant. Sidelay is the term used both for the edge of the printed sheet and the mechanical device on the press which determines the position.

Signature: In printing and binding, a printed sheet after it has been folded. Also called a section.

Slurring: In litho printing, the dragging of the wet ink which causes the dots to elongate in the direction the press travel.

Spine glued: A product which is held together with a thin film of adhesive running down the spine of each page. Can be produced in-line on some web presses.

Spiral Binding: A book bound with wires in spiral form inserted through holes punched along the binding.

Spot varnish:  The application of varnish to selective areas to create a highlight or contrast effect.

Step-and-Repeat: The multiple exposure of an image by stepping it in multiple positions and exposing in each position to create a repeat pattern using one original image.

Stock: The wet pulp before it is fed onto a papermaking machine, or during the papermaking processes before it becomes a sheet of paper; contains around 99% water and 1% fibre. Also the colloquial term for the paper type used in a printed job.

Substrate: The piece of material printed (e.g. paper, board, plastic, tin).

Tack: That property, governed by viscosity and adhesion, which renders a film of printing ink sticky to the touch.

Tint: Screening or adding white to a solid colour in order to lighten that specific colour. In lithography, the tint is achieved by creating dots to reduce the strength of the solid colour.

Tolerances: The specification of acceptable variations in a range of printingparameters to take account of the imperfections in each process.

Trapping: 
To print a wet ink film over previously printed ink.
Dry trapping is printing wet ink or varnish over dry ink. Wet trapping is printing wet ink or varnish over previously printed wet ink.

Trim Marks: In printing, marks placed on the copy to indicate where the papershould be trimmed.

Undercut: In printing presses, the difference between the radius of the cylinder bearers and the cylinder body, to allow for plate (or blanket) and packing thickness.

Undercolour Removal: 
Technique of making colour separations such that the amount of cyan, magenta and yellow ink is reduced in shadow areas while the amount of black is increased. Abbreviated UCR.

Up: In printing, the number-“Up” is the number of unique images on the printed sheet e.g. an A4 image fits 4- up on an SRA2 sheet

UV Varnish: A liquid coating applied to a printed sheet for protection andenhancement, which is dried immediately by exposure to UV light.

Varnishing: The application of any form of liquid varnish to printed matter in order to enhance its appearance or increase its durability.

Vignette: A design or illustration in which the background fades gradually away to white.

Viscosity: The amount of tack and flow of a printing ink or varnish.

Web: The roll of paper used in web or rotary printing.
Colloquial term for a web offset printing press.

Web Offset: The offset printing process on a press which prints on a roll or web of paper.

Web Press: A press which prints on a roll or web of paper.

Wire-0 Binding: A continuous double series of wire loops run through punched slots along the binding side of a booklet.

Wire Side: Side of the paper that rests against the manufacturing wires during papermaking. Typically the rougher side of the paper.

With the Grain: Parallel to the grain direction of the fibres of the paper or board, as opposed to against the grain.

Woodfree: Paper with no mechanical wood pulp. Woodfree papers actually contain wood pulp which has been chemically treated to enhance the whiteness of the paper.

Work and Tumble: In sheetfed printing, to print one side of a sheet paper, then turn it over from grip edge to back (leave) edge, using the same plate and sidelay to print the second side but using a different grip edge.

Work and Turn: In sheetfed printing, to print one side of a sheet paper, then turn it over from left to right and print the second side using the same grip and plate but opposite sidelay.