Glossary of Printing Terms

This glossary of printing terms was created by people working in today's printing industry and is brought to you by the Corktown Printing Company. It has been revised and edited to help the casual print buyer understand printing terminology. We have rewritten some technical descriptions in every day language to help the non technical person. Any suggestions that you may have on how we can improve this glossary will be carefully considered. Please send your comments and any new definitions to info@corktownprinting.com

4-colour-process: Printing that combines the four basic colours (Cyan, Magenta, Yellow, Black) to create a full colour picture.

Accordion fold: Bindery term - two or more parallel folds which open like an accordion.

Against the grain: At right angles to direction of paper grain.

Alteration: Change in copy or specifications after production has begun.

Author's corrections: Also know as "AC's". Changes  to copy after it has been typeset.

Aqueous coating: Also known as "AQ" is a quick drying coating applied to a printed sheet as it exits the press - used to speed up production and add luster.

Back up: Printing the second side of a sheet already printed on one side.

Banding: Method of packaging printed pieces of paper using rubber or paper bands.

Basis weight: Weight in pounds of a ream of paper cut to the basic size for its grade.

Bind: To fasten sheets or signatures with wire, thread, glue, or by other means.

Bindery: The finishing department of a print shop or firm specializing in finishing printed products.

Blanket: The thick rubber mat on a printing press that transfers ink from the plate to paper.

Bleed: Printing that goes to the edge of the sheet after trimming.

Blind embossing: An image pressed into a sheet without ink or foil.

Bond paper: Strong durable paper grade used for letterheads and business forms.

Brightness: The brilliance or reflectance of paper.

Bulk: Thickness of paper stock in thousandths of an inch or number of pages per inch.

Bulk pack: Boxing printed product without wrapping or banding.

Burn: Exposing a printing plate to high intensity light or placing an image on a printing plate by light.

Butt: Joining images without overlapping.

Butt fit: Printed colours that overlap one row of dots so they appear to butt.

Carbonless: Often referred to as NCR, pressure sensitive writing paper that does not use carbon.

Caliper: Paper thickness in thousandths of an inch.

Case bind: A type of binding used in making hard cover books using glue.

Cast coated: Coated paper with a high gloss reflective finish.

Coated paper: A clay coated printing paper with a smooth finish.

Collate: A finishing term for gathering paper in a precise order.

Colour bar: A quality control term regarding the spots of ink colour on the tail of a sheet.

Colour break: To separate mechanically or by software the artwork parts to be printed in different colours.

Colour correction: Methods of improving colour separations.

Colour matching system: A system of formulated ink colours used for communicating colour, Pantone Matching System (PMS) for example.

Colour separations: The process of separating artwork, photographs, and type into the four primary printing colours (CMYK).

Comb bind: To plastic comb bind by inserting the comb into punched holes.

Continuous-tone copy: Illustrations or photographs containing gradient tones from black to white or light to dark.

Contrast: The tonal change in colour from light to dark.

Copy: All furnished material used in the production of a printed product.

Cover stock: A heavy printing paper used to cover books, make presentation folders, etc.

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

Crimping: Puncture marks holding business forms together.

Crop: To cut off parts of a picture or image.

Crop marks: Printed lines showing where to trim a printed sheet.

Crossover: Printing across the gutter or from one page to the facing page of a publication.

Cyan: One of four standard process colours. The blue colour.

Densitometer: A quality control devise to measure the density of printing ink.

Density: The degree of colour or darkness of an image or photograph.

Die: Metal rule or imaged block used to cut or place an image on paper in the finishing process.

Die cutting: Cutting shapes or images into or out of paper.

Dot: An element of halftones. Using a loupe you will see that printed pictures are made of many dots.

Dot gain or spread: A term used to explain the difference in size between the dot on plate vs paper.

Draw-down: A sample of ink and paper used to evaluate ink colours.

Drop-out: Portions of artwork that do not print.

Dummy: A rough layout of a printed piece showing position and finished size.

Duotone: A halftone picture made up of two printed colours.

Emboss: Pressing an image into paper so that it will create a raised relief.

Emulsion: Light sensitive coating found on printing plates and film.

Eurobind: A patented method of binding perfect bound books so they will open and lay flatter.

Flood: To cover a printed page with ink, varnish, or other coating.

Flop: The reverse side of an image.

Foil: A metallic or pigmented coating on plastic sheets or rolls used in foil stamping and foil embossing.

Foil emboss: Foil stamping and embossing a image on paper with a die.

Foil stamping: Using a die to place a metallic or pigmented image on paper.

Forest Stewardship Council (FSC)™: The Forest Stewardship Council is an international not for-profit, multi-stakeholder organization established in 1993 to promote responsible management of the world’s forests.

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

Galley proof: Text copy before it is put into a mechanical or desktop layout.

Gang: Getting the most out of a printing press by using the maximum sheet size to print multiple images or jobs on the same sheet. A way to save money.

Generation: Stages of reproduction from original copy. A first generation reproduction yields the best quality.

Ghost bars: A quality control method used to reduce ghosted image created by heat or chemical contamination.

Ghosting: A faint printed image that appears on a printed sheet where it was not intended.

Gloss: A shiny look reflecting light.

Grain: The direction in which the paper fibers lie.

Grippers: The metal fingers on a printing press that hold the paper as it passes through the press.

Hairline: A very thin line or gap about the width of a hair or 1/100 inch.

Halftone: Converting a continuous tone to dots for printing.

Hard copy: The output of a computer printer or typed text sent for formatting.

Hickey: Reoccurring unplanned spots that appear in the printed image caused from dust, lint, dried ink.

High-bulk paper: A paper made thicker than its standard basis weight.

Highlight: The lightest areas in a picture or halftone.

Image area: Portion of paper on which ink can appear.

Imposition: Positioning printed pages so they will fold in the proper order.

Impression: Putting an image on paper.

Imprint: Adding copy to a previously printed page.

Indicia: Postal information placed on a printed product.

Ink fountain: The reservoir on a printing press that holds the ink.

Keylines: Lines on mechanical art that show position of photographs or illustrations.

Kiss die cut: To cut the top layer of a pressure sensitive sheet and not the backing.

Knock out: To mask out an image or type from a background.

Laid finish: Simulating the surface of handmade paper.

Laminate: To cover with film, to bond or glue one surface to another.

Line copy: High contrast copy not requiring a halftone.

Lines per inch: The number of rows of dots per inch in a halftone.

Loupe: A magnifying glass used to review a printed image or plate and position film.

Magenta: Process red, one of the basic colours in process colour.

Makeready: All the activities required to prepare a press for printing.

Matte finish: Dull paper or ink finish.

Micrometer: Instrument used to measure the thickness of different papers.

Middle tones: The tones in a photograph that are approximately half as dark as the shadow area.

Moire: Occurs when screen angles are wrong causing odd patterns in photographs.

Offsetting: Using an intermediate surface to transfer ink. Also, an unpleasant happening when the images of freshly printed sheets transfer images to each other.

Offset paper: Term for uncoated book paper.

Ok sheet: Final approved colour inking sheet before production begins.

Opacity: The amount of show-through on a printed sheet. The more opacity or the thicker the paper the less show-through.

Outline halftone: Removing the background of a picture or silhouetting an image in a picture.

Overprint: Two or more layers of ink on top of each other.

Overrun or overs: Copies printed in excess of the specified quantity.

Page count: Total number of pages in a book including blanks.

Pattern carbon: Special carbon paper used in business forms that only transfers in certain areas.

Perfect bind: A type of binding that glues the edge of sheets to a cover like a telephone book.

Perfecting press: A sheet fed printing press that prints both sides of a sheet in one pass.

Pica: Unit of measure in typesetting. One pica = 1/6 inch.

Picking: Printers nightmare that occurs when the surface of a sheet lifts off during printing. Generally a paper manufactures quality control problem.

Plate gap: Gripper space. The area where the grippers hold the sheet as it passes through the press.

PMS: The abbreviated name of the Pantone colour Matching System.

Point: For paper, a unit of thickness equaling 1/1000 inch. For typesetting, a unit of height equaling 1/72 inch.

PostScript: The computer language most recognized by printing devices.

Press number: A method of numbering business forms or tickets.

Pressure-sensitive paper: Paper material with self sticking adhesive covered by a backing sheet.

Process blue: The blue or cyan colour in process printing.

Process colours: Cyan (process blue), magenta (process red), yellow (process yellow), black (process black).

Ragged left: Type that is justified to the right margin and the line lengths vary on the left.

Ragged right: Type that is justified to the left margin and the line lengths vary on the right.

Rainforest Alliance: The Rainforest Alliance is a non-governmental organization (NGO) working to conserve biodiversity and ensure sustainable livelihoods by transforming land-use practices, business practices and consumer behavior.

Ream: Five hundred sheets of paper.

Recto: Right-hand page of an open book.

Register: To position print in the proper position in relation to the edge of the sheet and to other printing on the same sheet.

Register marks: Cross-hair lines or marks on film, plates, and paper that guide strippers, platemakers, pressmen, and bindery personnel in processing a print order from start to finish.

Reverse: The opposite of what you see. Printing the background of an image. For example; type your name on a piece of paper. The reverse of this would be a black piece of paper with a white name.

RIP: A computer that creates the colour separations of the final art, readying it for output to printing plates or digital press.

Saddle stitch: Binding a booklet or magazine with staples in the seam where it folds.

Scanner: Device used to make colour separations, halftones, duo tones and tri tones. Also a device used to scan art, pictures or drawings in desktop publishing.

Score: A crease put on paper to help it fold better.

Screen angles: The pre determined angles at which halftone, duo tones, tri tones, and colour separations are placed to make them look right.

Self-cover: Using the same paper as the text for the cover.

Shadow: The darkest areas of a photograph.

Show-through: Printing on one side of a sheet that can be seen on the other side of the sheet.

Side guide: The mechanical register unit on a printing press that positions a sheet from the side.

Side stitch: Binding by stapling along one side of a sheet.

Signature: A sheet of printed pages which when folded become a part of a book or publication.

Silhouette halftone: A term used for an outline halftone.

Skid: A pallet used for a pile of cut sheets.

Specifications: A precise description of a print order.

Spine: The binding edge of a book or publication.

Split fountain: Putting more than one ink in a printing fountain to achieve special colour affects.

Spoilage: Planned paper waste for all printing operations.

Spot varnish: Varnish used to highlight a specific part of the printed sheet.

Spreads: Reader - In the same sequence one would read. Printer - Sequenced in order to produce a bound copy.

Stamping: Term for foil stamping.

Step-and-repeat: A procedure for placing the same image in multiple places.

Stet: A proof mark meaning let the original copy stand.

Stock: The material to be printed, usually paper and sometimes plastic.

Substance weight: A term of basis weight when referring to bond papers.

Substrate: Any surface on which printing is done.

Tints: A shade of a single colour or combined colours.

Transfer tape: A peel and stick tape used in business forms.

Transparency: A positive photographic slide on film allowing light to pass through.

Transparent ink: A printing ink that does not conceal the colour under it.

Trapping: The ability to print one ink slightly over the other along the edges to avoid gaps if fit isn't exact.

Trim marks: Similar to crop or register marks. These marks show where to trim the printed sheet.

Trim size: The final size of one printed image after the last trim is made.

Under-run: Production of fewer copies than ordered. See over run.

Up: Printing two or three up means printing multiple copies of the same image on the same sheet.

UV coating: Liquid laminate bonded and cured with ultraviolet light. Environmentally friendly.

Varnish: A clear ink applied to printed surfaces for looks and protection. Can be applied to a specific area or overall.

Verso: The left hand page of an open book.

Vignette halftone: A halftone whose background gradually fades to white.

Washup: Removing printing ink from a press, washing the rollers and blanket. Certain ink colours require multiple washups to avoid ink and chemical contamination.

Waste: A term for planned spoilage.

Watermark: A distinctive design created in paper at the time of manufacture that can be easily seen by holding the paper up to a light.

Web: A roll of printing paper.

Web press: The name of a type of presses that print from rolls of paper.

Wire O: A bindery trade name for mechanical binding using double loops of wire through a hole.

Wire-O binding: A method of wire binding books along the binding edge that will allow the book to lay flat using double loops. See Wire O.

With the grain: Folding or feeding paper into the press or folder parallel to the grain of the paper.

Work and tumble: Printing one side of a sheet and turning it over from the gripper to the tail to print the second side using the same side guide and plate for the second side.

Work and turn: Printing one side of a sheet and turning it over from left to right ussing the same side guides and plate for the second side.

Wove paper: A paper having a uniform unlined surface with a smooth finish.

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