Paper Stock

Bond Paper - paper used for printing, writing, or typewriting. It may contain all chemical wood pulp or 25%, 50% or 100% rag pulp. Several grades are available, and the best are usually watermarked.

Brightness - the ability of a paper to reflect light. Brightness of paper is expressed as a percentage that is obtained by comparing the paper to be tested with a sample paper, called a "calibration sample".

Cotton Fiber Content Paper - paper containing some percentage of cotton fiber, gererally either 25%, 50%, or 100%.

Grain Direction - in paper, the predominant alignment of fibers corresponding to the direction in which the paper flows on the papermaking machine. Grain direction is often important if the paper has to be folded after it is printed.

Index/Bristol Stock - a class of heavyweight papers used for post cards, index cards, and other similar applications. Basis weights for index and bristol stocks range from 67 to 220 pounds.

Opacity - the quality of being impenetrable by liquids or light. With printing paper it is the ability to keep photos and print from showing through to the other side.

Per "M" - a reference for "per thousand". "M" is the roman numeral for the quantity of 1000.

Pulp - a mixture of wood and/or cotton fibers, chemicals and water which paper mills use to make paper.

Rag Paper - another term for "cotton fiber content paper".

Ream - five hundred sheets of paper. A ream is often confused with a package of paper which is incorrect. Paper is sometimes packaged in quantities of 250 as well as 500 sheets.

Text/Writing Papers - a general term used to describe paper with fine or specialty textures that is used for printing. Usually made from chemical wood pulp, sometimes with cotton fiber content. Often writing grade papers will feature a "watermark".

Watermark - a design, or symbol impressed in paper while it is being formed on the wet end of the paper making machine. When the paper is held up to the light, the watermark appears as a lighter area than the rest of the paper.

Paper Stock Finishes

Felt Finish - a finish created at the wet end of the paper making machine using distinctive patterns to create a similar texture on finished sheets.

Laid Finish - a paper finish exhibiting a ribbed appearance produced by the use of side-by-side wires on the dandy roll section of the paper making machine.

Linen Finish - a paper finish produced by compressing the paper between linen-patterned felts during paper making.

Wove Finish - a relatively smooth paper finish that is achieved by moderate calendering.

Printing

Blanket - a covering on the print cylinder of an offset press. The blanket receives the impression image from the printing plate and transfers it to the paper.

Bleed - the extension of an image beyond the trimmed edge or edges of a page.

Color Separations - the division of colors of a multicolored original into basic pieces, each of which will be reproduced by a separate printing plate. The colors are then assembled in the proper order during the printing process. See: Understanding Color Separations

Four Color Process - a technique of printing that uses the three process ink colors (yellow, cyan, magenta) and black to simulate color photographs and illustrations.

Gripper Space - on a sheet-fed offset press, the amount of space required for the grippers (i.e., the devices that pull the paper through the press) to grasp the leading edge of the paper. Gripper space can vary depending on the type of press, but usually it ranges between 1/4" to 5/8".

Halftone - a reproduction of continuous tone artwork (such as photographs) that breaks up the image into closely spaced dots. The spacing and variations in dot size give the final image the illusion of dimension and value.

Negative - a reverse photographic image on film or paper in which the dark areas appear light and the light areas appear dark.

Offset - the unintentional transfer of ink from one printed sheet to another.

Offset Plate - a plate typically made from metal or paper and is used to carry an image to the blanket of the offset printing press.

PMS Ink Colors - a term used to refer to the colors in the Pantone Matching System. Pantone Matching System is the trade name of the color matching system used by printers to specify ink colors for printing. A specific formula is used to produce each shade of ink, and each shade is assigned a specific number often refered to as a "PMS Number".

Thermography - a process that produces a raised effect using ink. Freshly printed ink is first dusted with a resinous powder and then subject to heat. The resin melts to form a glossy raised impression.

Bindery Operations

Collate - to organize, gather, and assemble the various parts of a printed piece or business form.

Jog - to straighten or align sheets of paper in a stack.

Padding - a method of binding sheets together, using adhesives, to make pads.

Perforation - a series of cuts or holes manufactured on a sheet of paper to weaken it in a certain spot for easy tearing.

Saddle Stitching - a method of binding in which wire staples are inserted through the fold of a printed piece at the spine and clinched in the center of the center spread, so that the pages lie flat when the printed piece is opened.

Scoring - a finishing process that allows paper, especially cover stock, to be folded easily without cracking.