Glossary of common print terms

4 color, 4 over 4, (4/4)	See CMYK
Accordion fold	Parallel folds in a print piece, each folding in the opposite direction than the previous. Also "Z-fold".
Aqueous coating	A plastic coating applied over the press sheet to protect, reduce fingerprinting, and speed drying. The result is a more saturated look. Available as gloss, semi-gloss, dull, and specialties such as 'soft-touch'. Aqueous coating uses a blanket, not a plate, and thus covers the entire press sheet. For 'spot' finishing, use varnish or UV coating.
Bleed	Ink extending past the crop marks so that, when trimmed, the ink is flush with the paper edge.
Case binding	Hard cover book binding.
CMYK	Cyan, Magenta, Yellow and blacK. Color printing is actually dots composed of these 4 "process" colors.
Coated stock	Paper coated with clay or plastic, typically resulting in a higher gloss.
Crop marks	Lines at the corners of the page showing where the page should be trimmed.
Die cut	A finishing technique to cut non-rectangular shapes, similar in concept to a cookie cutter. A sharp steel rule that cuts designed shapes directly into one or many sheets of paper.
dpi	"Dots Per Inch" of a linescreen. The higher the dpi, the finer the print quality. Newspapers are typically 65-100 dpi, quality offset color printing is typically 300dpi or higher.
Duotone	An image reproduced in two ink colors, typically a dark base color such as black, and a lighter "highlight" color. Tritone and Quadritone are also possible.
Emboss	A finishing technique with a solid die that stamps a piece of paper with a design, raising the paper in the pattern of the die stamp. Also can lower an area of the paper ("de-boss")
Endpapers	Papers glued front and back to the inside of "Case Bound" book covers and the "Text Block".)
Gate fold	Fold in half, then each half folded in again, resulting in four panels. Binding reference
GRACol	GRACoL stands for the General Requirements for Applications in Commercial Offset Lithography. GRACoL is a color reproduction Specification for sheetfed offset lithography. GRACoL reference
Indigo	A brand of digital printing press. Now owned by HP, it produces the highest quality digital printing. Papers for Indigo must be specially coated.
I-Tone	A brand of coating for Indigo papers.
Leaf	A sheet of paper. Each side is a "page".
Metallic ink	A specialty printing ink with flecks of metal combined into it to simulate a gold, silver or bronze surface. Not available in digital.
Page	One side of a sheet ("leaf") of paper.
Pantone, PMS	Pantone Matching System, the industry-standard color matching system. Colors are identified by Pantone swatch number.
Perfect bound	Square-edge spine binding. Typically requires at least 24 leaves. May be Smythe-sewn for additional strength.
Press sheet	The sheet of paper as it runs through the press, before trimming or folding.
Printing plate	In offset printing, each color requires a plate with the portion of the image to be printed in that color. Typically aluminum, the plate is etched by a laser from the electronic file in a platesetter.
Process color, 4/c process	See CMYK
Reflective/Subtractive color	The color system used in printing. Starting from white light, portions of the spectrum are removed using ink. The opposite of "Transmissive/Additive Color"
Registration	The alignment of two or more adjacent elements, otherwise: "Out of register". See "Trapping".
Roll fold	Parallel folds, each folding arond the previous.
Saddle stitch	A basic binding method that involves sewing/stapling pages at the spine. Requires page counts in multiples of 4.
Signature	A large press sheet with multiple pages later folded and trimmed during binding.
Stock	Printing term for paper: The type of paper, weight, finish, color, etc. Text stock is lighter as used inside a book; Cover stock is heavier.
SWOP	Specifications for Web Offset Publications. A set of specifications and tolerances for publication printing that ensures measurable, consistent reproduction in multiple publications. www.swop.org
Transmissive/Additive color	Color created by mixing light of two or more different colors, typically red, green, and blue. The color system used in electronic display. The opposite of "Reflective Color"
Trapping	A slight overlap of adjacent inks to achieve "register", creating a darker edge of the overlapped colors to avoid the much more visible white space if out of register..
Varnish	Solvent based offset protective coating inferior to aqueous because thinner and because it yellows. Typogram typically does not use varnish except when tinted for subtle design effects.