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Catalog Printing Glossary & Terms
Actual Weight: The true weight of any volume of paper used to determine both purchase price and shipping costs.
Aqueous Coating: A water based coating applied after printing, either while the paper is still on press "in-line" or after it's off press, giving the paper a gloss, dull, or matte finish, and helping to prevent the underlying ink from rubbing off.
Basic Size: The customary sheet size used to establish the bases weight of a ream (500 sheets) of a given grade of paper. Standard basic sizes vary by paper grade. ie: The basic size of book paper is 25" x 38", while the basic size of cover stock is 20" x 26".
Basis Weight: The weight, in pounds, of a ream of paper cut to a basic size. Each major paper grade, like cover, bond, or offset, has its own basic sheet size, which determines its basis weight. ie: The basic size of book paper is 25" x 38" for 500 sheets; therefore, 500 sheets of 70 lb. offset book paper in 25" x 38" will actually weight 70 pounds. Although the sheets in a given ream of paper may be larger or smaller than this example, basis weight refers to how much that ream would weigh if all the sheets were the related basic size.
C1S: Paper that is coated on one side only.
C2S: Paper that is coated on both sides.
Caliper: The thickness of a single sheet of paper, as measured with a sensitive tool called a micrometer, and expressed in units of thousandths of an inch.
Coated Paper: Paper with an outer layer of coating applied to one or both sides. Coated papers are available in a variety of finishes, like gloss, dull and matte. They tend to have good ink holdout and minimal dot gain, which can be especially important for recreating sharp, bright printed images, black and white halftones, and four color process images. The smooth surface of coated papers also helps to reflect light evenly.
Dot Compensation: Adjusting the size of the dots in halftones or four-color images to allow for dot gain and to ensure that the color and detail of the image print as intended.
Direct-to-Plate: The process for creating printing plates direct from digital page files bypassing the traditional film creation step. Direct-to-plate workflows promise to reduce cost and speed throughput by eliminating the need for expensive film.
Dot Gain: The tendency for the dots of halftones and four-color images to print larger than they are on the film or plate. If the printer or color house does not compensate for this, images may be distorted, appearing darker or less vivid than intended.
DPI: (dots per inch) The number of dots that fit horizontally and vertically into a one-inch measure. Generally, the more dots per inch, the more detail is captured, and the sharper the resulting image.
Dummy: An unprinted mock-up of a book or catalog. A dummy is made of the same paper stocks that will be used in the finished piece, and serves as a reference for the client, designer, printer, mailing house or distributor.
Film: The traditional "middle-man" in the process of creating printing plates. Digital files or "stipped" manual pages would first be exposed onto film. The film would then be used to photomechanically create the printing plate.
Form: The assembled pages and images as printed on a single or double web. With the correct imposition, the pages of a form will be in correct order after coming off the press. When completed on the press a form becomes a signature.
Hickey: An irregularity in the ink coverage of a printed page. Hickeys are caused by paper dust, dirt, or pick out on the printing blanket, all of which prevents the ink from adhering to the paper surface.
Imposition: The process of arranging the film pages or digital file pages into the correct layout so that the form, when printed and folded on the press and gathered with other signatures in bindery produces a book or catalog with the pages in the correct final order. Imposition also takes into account page creep - the added width of a page needed to wrap around inner pages - by nudging the placement of the page in small increments. Page creep is generally an issue on catalogs of 64 pages or more.
Jog: To shake a stack of papers or books, either on a machine or by hand, so that the edges line up.
Moire: A pattern created by printing several repetitive designs on top of each other. In four-color process printing, 4 screens of colored dots print on top of each other. If the angles of the halftone screens of each of the 4 colors are not properly aligned with each other, an undesirable, blurry pattern called "moire" appears in the final image.
Opacity: A measure of how opaque a paper is. The more fibers a paper has, the more opaque it is, and the less it allows "show-through" of the printing on the back side or on the next page. Opacity isn't always determined by thickness or weight; a thinner paper may have more opacity than a thicker paper if opacifying thickeners are used.
PMS Ink: The Pantone Matching System (PMS) is the most widely used system for specifying and blending match colors. It provides designers with swatches for specific colors, and gives printers the recipes for making the colors.
Perfect Bind: A binding process using a glue to bind the pages of a catalog or book to a separate cover like a paperback book. This process also produces a visible flat spine. This bindery process is required for catalogs that exceed the capacity of saddle stitching.
Picking: A problem generally resulting from using an ink that's too tacky for the paper it's printed on. The ink actually pulls tiny pieces of the paper off the surface of the sheet.
Plate: The printing plate, generally a thin sheet of metal that carries the printing image. The plate surface is treated or configured so only the printing image is ink receptive.
Process Ink: The four process colors; cyan (process blue), magenta (process red), yellow, and black used to print four-color images. The colors are also referred to as CMYK respectively (K signifying black).
Registration: Putting two or more color plates together so that they are exactly aligned and the resulting image is sharp.
Saddle Stitched: Binding folded sheets or signatures of paper are gathered together, one inside the other, placed over a "saddle", and stitched or stapled along the spine with wire. Saddle stitched books will lie flat when open, but may contain only a limited number of pages as determined by the thickness of the paper used.
Trapping: Printing ink over previously printed ink. Trapping is also used to describe the very slight overlapping of adjacent colors or images to prevent a gap in printing between two items that touch.
Varnish: A coating printed on top of a printed sheet to protect it, and a finish, and/or add a tinge of color. An entire sheet may be varnished, or certain areas, like halftones, may be spot varnished to add emphasis and appeal.
Web Paper: Paper that comes in a roll rather than in sheets. A web press prints this paper, folding and/or cutting it "in-line."
Web Press: A press specifically designed to print rolls of paper called webs. A web press runs much faster than a sheet-fed press: as many as 40,000 images per hour verses a maximum of about 14,000 per hour on a sheet-fed press.