P

packing - In printing presses, the paper or other material used to underlay a press blanket or plate, to bring the surface to the desired height; the method of adjusting squeeze pressure.

packing gauge - a device for determining the relationship between the height of the plate or blanket, and the cylinder bearers.

padding glue - A flexible glue used in padding loose sheets.

page flex - The number of flexes a book page can withstand before loosening from the binding.

page makeup - In stripping, assembly of all elements to make up a page. In digital imaging, the electronic assembly of page elements to compose a complete page with all elements in place on a video display terminal and on film or plate.

page proofs - Initial impression of a page pulled for checking purposes before the entire job is run.

pages-per-inch (ppi) - In book production, the number of pages contained in a one-inch stack of paper.

pagination - In computerized typesetting, the process of performing page makeup automatically.

palette - The collection of colors or shades available to a graphic system or program.

pallet - A wooden platform with stringers wide enough to allow a fork lift to drive into it and lift; used to pack cartons for shipment, if specified by the customer. Pallets are usually not reusable.

panchromatic - A type of film equally sensitive to light in all colors.

Pantone Matching System - See PMS.

paper machine - Machine on which paper is manufactured, dried, wound on rolls and slit to appropriate lengths.

paper master - A paper printing plate used on an offset-duplicator. The image is made by hand drawing, typewriter or electrophotography.

paper surface efficiency - Measure of the printability of a sheet of paper which is dependent upon the amount of ink the paper absorbs, the smoothness of its surface, and the evenness of its caliper.

paperbound - A paper-covered book; also called paperback or soft cover.

papeterie - A paper used for greeting cards, stationery, etc. which is distinctive from regular stock in that special watermarks and embossing may be used.

paraded watermark - See watermark.

parallel fold - Any series of folds in sequence, made in parallel fashion.

paste drier - In inkmaking, a type of dryer, usually a combination of drying compounds.

pasted - Pasted grades are those grades of paper or paperboard made up of layers pasted together. The process is machine operation used to combine sheets of the same or different papers into a single thickness.

paste-up - Assembling on one page for photographing various art elements for a print order.

PCF – see Process Chlorine-Free.

PCW – see Post-Consumer Waste.

percent tensile - A paper's tensile strength expressed in percentage points.

perfect binding - Method of binding books in which all the pages are converted to single sheets. They are then held in a clamp and attached to a cover with an adhesive.

perfect casebinding - To bend by gluing signatures to a case made of binder board covered with fabric, plastic or leather yielding a hard cover book.

perfecting press - (Commonly referred to as Perfector) Press which prints both sides of the sheet of paper at the same point. On the offset press, each cylinder serves as the impression cylinder for the other.

perforate - Punching a series of holes or slits in a line in the paper, to weaken it so tearing will occur easily along that line. Also the making of slits in paper during folding, at the fold, to prevent wrinkles and to allow air to escape.

perforating rule - Blade for cutting impression which can be taped to the cylinders of an offset press.

perforation tear strength - The ease or difficulty with which a perforation may be torn.

permanence - In paper terminology permanence refers to the ability of paper to retain, for a given period of time, desirable properties such as color, and folding endurance. Prolonged exposure to light, humidity, and adverse temperatures will affect the permanence of paper.

pH value - Degree of acidity or alkalinity measured on a scale from 0 to 14 with 7 the neutral point. Measurement of pH is important to quality control in making paper and pigments and in the preparation of platemaking chemicals. pH control of press fountain solutions is also essential to assure maximum plate-life and uniform ink drying. From 0 to 7 is acid; from 7 to 14 is alkaline.

photoengraving - In letterpress, the process of creating a relief plate photochemically.

photomechanical - In platemaking, pertaining to any platemaking process using photographic negatives or positives exposed onto plates or cylinders covered with photosensitive coatings.

pica - Unit of measure, approximately 1/6 of an inch, used in graphic arts. Twelve points make one pica.

pick tester - An instrument designed to measure the pick resistance of paper, through the use of inks with varying degrees of tack.

picking - Fibers in the paper which tend to pull away from the surface during the printing process. This occurs when the tack or pull of the ink is greater than the surface strength of the paper.

PICT - In digital imaging, a standard data format in which most Macintosh illustrations are encoded.

pigment - Substance, usually mineral or inorganic compounds, used to give paper its color.

pile feeder - A mechanism on printing presses and folders, which feeds paper automatically from the top of the pile.

piling - In printing, the building up or caking of ink on rollers, plate or blanket; will not transfer readily. Also, the accumulation of paper dust or coating on the blanket of offset press.

pin register - In copy registration, the use of accurately positioned holes and special pins on copy, film, plates and presses to insure proper register or fit of colors.

pinholes - Tiny holes or imperfections on the surface of the paper caused by the presence of foreign matter on the paper surface during manufacture.

pinholing - Condition caused by failure of an ink to cover the surface completely, leaving small holes in the printed area.

pixel - Short for "picture element." A pixel is the smallest resolvable point of a raster image. It is the basic unit of digital imaging.

plastic comb binding - A binding made of plastic in the shape of a comb.

plate - Brief for printing plate; a thin sheet of metal that carries the printing image, whose surface is treated so that only that image is ink receptive.

plate cylinder - The cylinder of a press on which the plate is mounted.

plate finish - A hard finished paper.

plate flaking - This occurs primarily with offset plates with the copper-plate or image area having a tendency to chip off, the chip then moving into the ink train, plate or blanket.

platen - Flatbed for the printing form and a flat plate to apply pressure.

platen press (jobber) - A letterpress on which the printing form and the paper lie flat throughout the printing process.

plugged - Refers to a printing condition characterized by the loss of dot reproduction; no dots are visible.

PMS^® (Pantone Matching System^®) - An ink color system widely used in the graphic arts. There are approximately 500 basic colors, for both coated and uncoated paper. The color number and formula for each color are shown beneath the color swatch in the ink book.

pocket - (1) A station on the gathering line. (2) Paper, cloth, vinyl, or other material made into a pocket, with or without gussets, affixed inside the front or back cover of a book. A pocket may be made separately and glued in after binding or made over the lining sheet in a case.

poor trapping - In printing, the condition in wet printing in letterpress and lithography when less ink transfers to previously printed ink than to unprinted paper.

porosity - The degree to which a paper will allow the permeation of air, gas, or liquid, determined by the compactness of its fibers.

positive - In photography, film containing an image in which the dark and light values are the same as the original. The reverse of negative.

post-consumer waste (PCW) - Indicates material that is collected from end-users and recycled. PCW is the preferred form of recycled material because it reduces pressure on our remaining forests, saves water and energy, and diverts solid waste from our landfills.

PostScript - A page description language developed by Adobe Systems, Inc. to describe an image for printing. It handles both text and graphics. A PostScript file is a purely text-based description of a page.

pre-consumer waste - Is excess material from the manufacturing process that never made it to the consumer and is recycled back through the mill.

preflight - In digital pre-press, the test used to evaluate or analyze every component needed to produce a printing job. Preflight confirms the type of disk being submitted, the color gamut, color breaks, and any art required (illustrations, transparencies, reflective photos, etc.) plus layout files, screen fonts, printer fonts, EPS or TIFF files, laser proofs, page sizes, print driver, crop marks, etc.

prepress proof - A trial print made photographically before the plate has been made to eliminate the expense of making press proofs. See off-press proofs.

prescreen - A lower contrast halftone, printed on glossy photographic paper for direct pasteup with line copy, to avoid stripping of a halftone negative into a line negative.

presensitized plate - In photomechanics, a metal, film or paper base plate that has been precoated with a light-sensitive coating.

pre-separated art - Art that has a separate overlay prepared for each color in the illustration.

press - During manufacture the paper web passes through sets of rolls called the press. This occurs either to remove water from the web at the wet press: to smooth and level the sheet’s surface at the smoothing press; or to apply surface treatments to the sheet at the size press.

press proof - A few sheets are run off the press for a final proof.

press sheet - The full-size sheet of paper is selected for a job to be printed on a sheet-fed press. The sheet size is usually slightly larger than the negative flat, to allow for gripper and trim margins.

pressure-sensitive paper - Designates paper that is coated on one or both sides with adhesive. This adhesive is activated by pressure. Usually used in the manufacture of labels and tapes.

primary colors - The three basic colors — yellow, red, and blue — from which all other colors can be mixed.

print quality - In paper, the properties of the paper that affect its appearance and the quality of reproduction.

printability - How well a particular sheet appears after the printing process in regards to ink receptivity, uniformity, smoothness, compressibility and opacity. It involves a complex interrelationship of many paper properties. Best methods for predicting printability are those which simulate actual printing conditions and which are reproducible from test to test.

printer - Generic term applied to data-processing devices that produce full-size hard copy from computers. Several printers are used. Among impact printers: serial printers, line printers, chain printers, bar printers, wheel printers and matrix printers. Non-impact printers, like ink jet printers, are based on printing principles similar to those employed in cathode ray tubes.

printing pressure - The force or pressure between the blanket cylinder and impression cylinder required to transfer the ink from the blanket to the paper.

Process Chlorine-Free (PCF) - Indicates that fiber is recycled and is unbleached or bleached with non-chlorine compounds. PCF papers cannot be considered totally chlorine-free because of the unknown bleaching process of its recycled content.

process colors - In printing, the subtractive primaries: yellow, magenta and cyan, plus black in four-color process printing.

process inks - Transparent inks, finely ground and manufactured for use in the four-color process.

process plates - Two or more color plates in combination that produce other colors and shades.

process printing - The printing from a series of two or more halftone plates to produce intermediate colors and shades.

progressive color proofs (progs) - Proofs of colors separation negatives that have been exposed to offset plates and printed using process inks. Presented in the sequence of printing, i.e., (1) yellow plate alone, (2) red alone, (3) yellow and red, (4) blue alone, (5) yellow, red, and blue, (6) black alone, (7) yellow, red, blue, and black. The preferred way for checking the color of the separation negatives using the same inks, paper, ink densities, and color sequence as intended for the production run.

progressive proofs - For process-color printing, engravers prepare a set of proofs showing each color separately and in combination proofed in proper color and rotated. These proofs are essential guides for the printer.

proofread - Reading and correcting proofs early in production.

proofs - Samples of copy and layout produced at various stages of production. Following internal inspection, proofs are sent to the customer for approval.

proprietary mill brand - Paper retaining the name of the owner of the mill.

pull test - A test performed on perfect-bound books to determine the amount of pull pressure required to remove a page from the binding; used to verify that pages are securely bound.

pulp - Cellulose fiber material produced by chemical or mechanical means from which paper and paperboard is manufactured. Origins of this cellulose fiber are many and can include wood, cotton, straw, jute, bagasse, bamboo, hemp, various leaf fibers, reeds, etc. There are many mechanical and chemical means of separating the fiber from its original sources.

pulping - Process of transforming raw papermaking materials into pulp.

pulpwood - Wood, in the form of logs, or shorter lengths, that is suitable for the manufacture of wood pulp from which to make paper.