Glossary of Printing Terms

Glossary of Printing Terms

Acetate: A thin, flexible sheet of transparent plastic used to make overlays.

Bond paper: A grade of paper suited for letterheads, business forms etc.

Carbonless paper (ncr): Paper coated with chemicals that enable transfer of images from one sheet to another with pressure from writing or typing.

Cast coated: Coated paper with a very high gloss enamel finish.

Coated: Paper which has received a coating on one or both sides. Paper may be single, double or triple coated. The more layers of coating, the better quality. The finish may be gloss, silk or matt. Impress House sheet is triple coated (see uncoated).

Continuous stationery: Forms which are produced from reels of paper and then fan folded. These can be multi-part forms.

Uncoated: Paper that has no coating (see coated).

Match print: Ink jet proofing method using the same file that will create plates for data integrity.

PDF: An acronym for portable document format; a digital proof created using Adobe Acrobat.

Wet: Proof created using the plates and inks for the final print run. The most accurate way of proofing.

Digital: Digital proof from the digital press produced prior to printing digitally.

A/W: Abbreviation for artwork.

Backing up: Process of printing on the second side of a printed sheet.

Bitmap: A grid of pixels or printed dots generated by a computer to represent type and images.

Blanket: Thick rubber sheet that transfers ink from plate to paper on the press.

Bleed: The printed image extends beyond the trim edge of a sheet or page. A bleed may occur at the head, front, foot and/or gutter of a page.

Clipping path: An outline, embedded into the file, that tells an application which areas of a picture should be considered transparent when printing.

CMYK: An acronym for cyan, magenta, yellow and key (black); the four process colours combine together in varying proportions to produce the full colour spectrum.

Coating: Application of varnish to seal the ink and prevent marking.

Colour separation: Process by which a continuous tone colour image is separated into the four process colours (cmyk) for print production.

Crop: marks lines near the margins of artwork or photos indicating where to trim, perforate or fold.

CTP: An acronym for computer-to-plate; a process of printing directly from a computer onto the plate used by a printing press.

Digital printing: An image is sent directly to the printer using digital files such as pdf’s and those from graphics software such as Illustrator and InDesign. This eliminates the need for a printing plate, which is used in offset printing, which can save money and time. Benefits are for very short runs or for personalised print.

Dot gain: A printing defect in which dots print larger than intended, causing darker colours or tones due to the spreading of ink on stock. The more absorbent the stock, the more dot gain. Can also vary with type of ink. Dpi An acronym for dots per inch; dpi measures the quality of an image from a scanner or output resolution of a printer. The greater the dpi, the higher the quality will be. However, the larger the file size, the slower it will process.

Dummy: A mock-up made to resemble the final printed product. It uses the proposed grade, weight, finish and colour of paper.

Duotone: A method of enhancing a mono image using two colours.

Embed: Implies the inclusion of elements and data into a computer file necessary to maintain or change the elements when used remotely.

EPS: An acronym for Encapsulated PostScript, a computer file format widely used by the printing and graphics industries.

Font matching: A sometimes undesirable process, used when a chosen font is not available and the closest possible match is made, sometimes causing reflow of the text or other errors.

Format: Size, shape and overall style of layout or printed project.

Four-colour process: Reproduction of full-colour photographs or art with the four basic colours of ink (cyan, magenta, yellow, black).

Full colour: Or ‘four colour process’ using the four basic printing colours: cyan, magenta, yellow and black.

Greyscale: Shades of grey ranging from black to white; in printing, greyscale uses only a black halftone plate.

Grippers: Metal fingers which hold paper and carry it through printing impression to the delivery end of the press.

Gutter: Gap between two pages.

Halftone: Picture with varying shades of tone created by varying size dots.

Hickey: Spot or imperfection in printing that may occur when using another printing company!

Imposition: Positioning pages in a press-ready form so that they will be in the correct numerical sequence after folding.knockout A shape or object printed by eliminating (knocking out) all background colours.

Lithographic printing: A printing process based on the principle of the natural aversion of water to grease. The areas to be printed receive and transfer ink to the paper, the non-printing areas are treated with water to repel the ink.

LPI: Lines per inch – refers to the quality of a halftone screen. It is important to distinguish it from dpi which refers to the resolution of a device or image. Commonly lpi is used at exactly half of the dpi of the device or image, i.e. 300dpi would equal 150lpi.

Make-ready: The work associated with the set-up of printing equipment before running a job.

Metal plate: A metal sheet with a specially coated ’emulsion’ on its surface which when exposed through a film mask or by CTP process will produce an image. When the plate is loaded onto the printing press it then reproduces this image using inks onto the paper.

Micrometer: Instrument used for measuring the thickness of paper.

Offset printing: A method in which the plate or cylinder transfers an ink image to an offset or transfer roller, which then transfers the image to stock.

Origination: A term used to describe all of the processes which prepare a job for the printing stage.

Outline paths: A term used when converting a font or graphic into a mathematical vector format, can also be called ‘curves’.

Over-run: Copies printed in excess of the quantity specified in the order.

Pantone ® colour: Premixed ink colours that are often specified for printing as a spot colour. Can be matched using CMYK but will not be exactly the same colour as its Pantone colour counterpart.

Perfecting: Process of printing both sides of one sheet during a single pass through the press.

Process colour: Colour specified in percentages of cyan, magenta, yellow and black. When superimposed during printing the four colour printing process, their separate plates can recreate millions of different colours.

Proof: A representation of the finished print produced for customer inspection for errors prior to mass printing.

Registration marks: Crosses or other marks placed on artwork which ensure perfect alignment (‘registration’).

Resolution: The number of dots per inch (dpi) in a computer-processed document. The level of detail retained by a printed document increases with higher resolution. Ppi (pixels per inch) for an image.

Reversed-out: Type appearing white on a black or colour background, either a solid or a tint.

RGB: An acronym for red, green and blue. RGB is a colour model used for computer monitors and colour video output systems. Colour separations for litho printing can not be made directly from RGB files and need to be converted to CMYK first.

RIP: (raster image processor) Computer used to create an electronic bitmap for actual output. This may be built into an imagesetter or may be separate.

Scanning: The process of converting a hard copy into digital data ready for editing and design. The quality of the scan is dependent on the quality of the original, the scanning equipment and software as well as the experience of the operator!

Self-cover: The paper used inside a booklet is the same as that used for the cover and is generally printed on the same press run.

Solid: An area on the page which is completely covered by the ink.

Spot colour: Spot colour is not made using the process colours. Instead the colour is printed using an ink made exclusively. Each spot colour therefore requires its own separate printing plate. Spot colours do not apply to digital printing as the printing devices can only reproduce from the four process colours; cyan, magenta, yellow and black.

Spread: Two or more adjoining pages that would appear in view on sheet.

TIFF: Acronym for Tagged Image File Format. TIFF (.TIF) pictures can be black-and-white line art, greyscale or colour. This is a widely used format for image/photographic files but is unsuitable for text unless it is created at a very hi-resolution.

Tint: An area of tone made by a pattern of dots, which lightens the apparent colour of which it is printed.

Trapping: A slight overlapping between two touching colours that prevents gaps from appearing along the edges of an object because of misalignment or movement on the printing press.

Varnishing/sealing: The application of a varnish/sealant to a surface to offer protection against marking and improving its overall appearance.

Wash up: To clean ink from rollers, fountains and other components of a press.

Work and tumble: To print one side of a sheet of paper then turn the sheet over from gripper to back using the opposite gripper edge but the same side guide to print the second side.

Work and turn: To print one side of a sheet of paper then turn the sheet over from left to right and print the second side using the same gripper edge to print the second side.

Binding: Process of fastening papers together.

Blind emboss: Impression of an un-inked image onto the back of a sheet which produces a raised ’embossed’ image on the front of the sheet.

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

Close gate fold: As gate fold but with a final parallel fold in the centre to “close” the leaflet.

Collating: Gathering together sheets of paper from a book, magazine or brochure and placing them into the correct order.

Concertina fold: A method of folding in which each fold opens in the opposite direction to its neighbour, giving a concertina or pleated effect.

Crash number: Numbering paper by pressing an image on the first sheet which is transferred to all parts of the printed set.

Crease: To mechanically press a rule into heavy paper or board to enable it to be folded without cracking.

Creep: Phenomenon when middle pages of a folded section extend slightly beyond the outside pages.

Deboss: Image pressed into paper so it lies below the surface.

Die-cutting: Process of using sharp metal rules on a wooden block to cut out specialised shapes such as pocket folders or unusual shaped flyers etc.

Drilling: Drilling of holes in product which will allow insertion over rings or posts in a binder of some sort.

Embossing: A process performed after printing to stamp a raised (or depressed) image into the surface of paper, using engraved metal embossing dies, extreme pressure, and heat. Embossing styles include blind, deboss and foil-embossed.

Foil stamping: A metallic finish, or other embossed finishes applied by specialist equipment.

French fold: Two folds at right angles to each other.

Gate fold: Three panels to print onto where the outer panels are half the width of the inner panel and fold in to meet in the centre.

Kiss-cut: To die-cut but not all the way through the paper – commonly used for peel off stickers.

Lamination: A thin film coating which is applied to the paper or board to give a more glossy or matt appearance.

Loose-leaf: A method of binding which allows the insertion and removal of pages for continuous updating.

Perfect binding: A bookbinding method in which pages are glued rather than sewn to the cover. Used primarily for paperback books.

Saddle stitch: A binding process in which a pamphlet or booklet is stapled through the middle fold of its sheets using metal wires.

Score: To partially cut with a rule into heavy paper or board to break the grain to make folding cleaner and easier.

UV varnish: A liquid laminate that is bonded and cured with ultraviolet light.

Wire-o binding: A method wire binding books along the binding edge that will allow the book to lay flat.

Glossary of Printing Terms