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| Pad printing |
| An indirect gravure process in which a flexible (often semi-spherical) pad of silicon rubber is used as a medium for transferring the ink from the plate to the surface to be printed. This method can be used to print a great diversity of irregularly shaped objects. |
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| Page description language |
| A code or programming language used to specify all elements of the layout of a printed page including fonts, graphic elements and images, in such a way that an interpreter can carry out the necessary printer and control commands in an output device. |
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| Page assembly |
| The positioning of the finished pages on the imposition sheet as determined using imposition software. |
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| Page view (page impression, page request) |
| The number of times a Web page is requested from a server. This is the preferred counting method for traffic measurement (instead of hits) because it only counts documents, not individual files. A single HTML page is counted as one page impression. |
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| Pagination |
| The assigning of numbers to the pages in a document; the division of a document into pages |
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| Pantone colors |
| Colors based on a system used worldwide that the Pantone print shop (New Jersey) introduced for the graphic arts industry in 1963. The system is based on 512 reference color tones which are mixed from eight basic colors, black and white and are printed on coated and uncoated paper. Today, there are over 1,100 Pantone colors available on a broad range of papers. Pantone has also published color systems for textiles, plastics, paints, film and video. |
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| Paperboard (cover paper) |
| A paper product with a grammage that is higher than paper, but lower than cardboard. A distinction is made between single-layer and multilayer board. In the U.S., paperboard is often called “cover paper”. |
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| Papyrus |
| A durable writing material in roll, sheet or book form made from a giant sedge, Cyperus papyrus. To produce papyrus, the pith of the plant is sliced into strips that are laid out in a row with the edges slightly overlapping. Another row is then laid crosswire on top of the first. Next, the two layers are moistened with water and pounded into a sheet of writing material, smoothed and then dried. Papyrus was used as a writing material by the Egyptians since the beginning of the third century B.C. Beginning in the second century A.D. It was produced in Egypt in large quantities and transported throughout the ancient world. In time papyrus was replaced by parchment, which was in turn was replaced by paper. |
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| Paragraph format |
| Layout instruction and print command that determines text alignment, margin width and spacing. |
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| Parallel center fold |
| A folding technique in which the product is creased in the middle in order to halve the respective length in every pocket of the buckle folder. The page is folded in half and then folded in half again in the same direction. |
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| Parallel cut |
| A cut performed by setting the saddle (material stop) parallel to the cutting line. |
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| PARC (Palo Alto Research Center) |
| Organization established in 1970 by the Xerox Corporation that has had a decisive influence on the development of computer technology through the present. Among other achievements, the research institute developed the graphic user interface used on Macintosh and Windows computers, the first commercially available computer mouse, Ethernet network technology, client server architecture, object-oriented programming and the laser printer. |
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| Parchment |
| Specially treated animal skin for writing or printing. |
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| PCL (printer command language) |
| The language used to control computer printers. Introduced in the 1980s by computer manufacturers Hewlett-Packard and under constant development ever since, PCL allows application programs to control the functions of different printers in a standardized, efficient manner. |
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| PDF (portable document format) |
| Data format developed by Adobe Systems Inc. and used for exchanging and processing electronically stored, formatted documents with text and images, independent of hardware or software. One of the special features of the format is that texts and graphics are stored in vector form, meaning that the resolution of their representation is dependently solely on the output device (monitor, printer). |
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| Penumbra |
| See "deep shadow". |
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| Perceptual rendering |
| A rendering method used to preserve the visual color relationship as it is perceived by the human eye, and in which, thus, the color values themselves may change. The perception-oriented (perceptual) rendering intent reproduces the image taking into consideration paper, dynamic range and color characteristics of the output system, so that that the human eye perceives the image in the destination system (CMYK) true to the original. In color space conversions, one can choose from perceptual, absolute colorimetric and relative colorimetric. With perceptual all colors are shifted and compressed until the colors of the source color space fit into the destination color space. |
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| Perfecting machine |
| Usually a sheetfed press that prints on both sides of the paper in a single run. |
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| Periodical |
| Refers to a typesetting and printing job performed under a specific title on a regular basis with a similar layout. |
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| Personalized printing |
| Refers to print runs in which the individual copies have distinctive imprints. A minimum requirement for personalized printing is a digital printing process, which allows printing data to vary from copy to copy. |
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| Photocomposition |
| The first fundamentally new typesetting technology since the invention of letterpress printing by Johannes Gutenberg, photocomposition does not use solid forms for depicting the characters. Instead, the set text is created on photographic film. Older machines performed this function by imaging the characters with a flashlight from a negative original or from a very bright screen (cathode ray tube) onto the film. The move to computer setting is marked by the laser setter which, like the laser printer, uses a laser beam to write text, images and other design elements directly onto film or a printing plate. |
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| Photopolymer plate |
| A kind of plate with a flexible base material, excellently suited for use on rotary printing presses. Photopolymer plates have widely replaced stereotype plates. |
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| Photoshop |
| A software package for digital image manipulation in DTP applications designed and manufactured by Adobe. |
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| Pica |
| A type size used in the Anglo-Saxon world, corresponding to 12 points. |
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| Picking resistance (sizing strength) |
| Refers to the amount of force necessary to separate particles from the surface of the paper as it moves vertically. Picking resistance is a key criterion for offset-printing applications. |
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| Pigment color |
| A coloring element that is formed when white light strikes an object that reflects part of the spectrum while absorbing other regions and the remitted light has a different spectral distribution than the original light. Pigment colors are non-luminous, and can only be created through absorption or reflection of light. |
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| Pixel (picture element) |
| The smallest unit of a digitally displayed image. The memory required by an image consisting of pixels is determined by the size of the image, its resolution, the number of pixels per unit of area, and the number of colors to be displayed. |
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| Pixel format |
| A format for storing image data in which, for a given resolution every pixel in the image is represented by the corresponding data. Image processing programs such as Photoshop use the pixel format, the most common being TIFF (Tagged Image File Format). The pixel format is most suitable for real images, but, depending on the quality of the image, it requires large amounts of memory. |
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| Pixel graphic (bitmapped graphic) |
| A graphic or image represented as a matrix of picture elements or pixels. |
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| Plate characteristics |
| A representation of data and factors required for digital platesetters to control the output quality during production and defined using a control wedge. These characteristics must be checked regularly. |
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| Polarization filter (polfilter) |
| A transparent optical medium which only allows electromagnetic waves of one polarization to penetrate. Of the light waves normally moving in all directions, polarization filters only allow to pass those components of an oscillation that come from a certain direction. These directed light beams hit the measured object and are then reflected partly in a mirror-like way. Unlike diffuse reflection, direct reflection does not alter the oscillation direction of light. These components can be eliminated with a second polarization filter positioned at 90 degrees. Densitometers with polarization filters show identical values for wet and dry prints which are, however, slightly higher than on devices without polfilters. |
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| Polaroid |
| A process in which finished photographs are produced within the camera device itself; the first major development in photography since the genre was invented. The process works on the basis of developer substances in paste form, which are distributed over the imaged film after a photograph has been taken and act on the film by diffusion. This method was invented by Edwin Herbert Land (1909-1991), who founded the Polaroid Corporation in 1937, and launched the first Polaroid Land camera in 1947. This camera produced a black-and-white paper image one minute after the photograph had been taken. The millionth instant camera was sold in 1956. The first Polaroid color camera was launched in 1963. Polaroid declared bankruptcy at the end of 2001, as the technology has become obsolete, in large part due to the popularity of digital photography. |
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| Pop-up advertising |
| A method of advertising on the Internet, in which windows open automatically when a web page is accessed, usually partially hiding the content of the relevant page. |
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| Poster paper |
| Paper grade for large-format posters, mainly highly mechanical and heavily sized. |
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| Postpress |
| A general term for all processing operations performed on the printed product after the printing process itself is concluded. Examples of postpress procedures include folding, binding, trimming and packaging. |
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| Postprint |
| See "finishing". |
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| PostScript |
| A page description language developed by Adobe which has become a standard in the digital prepress stage. It describes documents largely independently of the device used, so that, for example. the resolution of an image is not defined until the output device has been determined. PostScript 2 offers improved colorimetric facilities, since the reference color space is integrated in accordance with the CIE standard. PostScript 3 also improves the way in which colors and three-dimensional objects are displayed and supports the trapping of graphic objects. |
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| Ppi (pixels per square inch) |
| Specifies the resolution of an image, as it appears on a monitor. |
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| Preflight check |
| The test or assessment made in the prepress process in which output is simulated and files are reviewed for the existence of all required fonts and graphics. This kind of check can also indicate whether image resolution is too low or too high, whether spot colors are improperly defined and can reveal other potential errors as well. |
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| Press characteristics |
| See "printing characteristics". |
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| Press proof |
| See "machine proof". |
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| Primary color (basic color) |
| One of the three colors that cannot be attained by mixing. When equal amounts of two primary colors are mixed, a first-order secondary color is produced. Every color model is comprised of three primary colors. The additive primary colors are red, green and blue (RGB). The subtractive primary colors are cyan, magenta and yellow (CMYK – K stands for key and refers to black for contrast). Each secondary color of the one color model is a primary color in the other. A second-order secondary color is produced by mixing different amounts of two primary colors. Tertiary colors are a combination of different amounts of all three primary colors. |
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| Primary pulps |
| The raw materials for paper manufacturing removed from virgin forest products by mechanical means (woodpulp) or by a chemical process (chemical pulp). |
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| Print and turn |
| See "work and turn". |
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| Printability |
| Refers to a range of paper properties that influence print results, including gloss, smoothness, whiteness and opacity.
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| Printing characteristics (characteristic curve, press characteristics) |
| A diagram which shows the extent of dot gain occurring in the printing process, and is the graphic representation of the relationship between the tone values of the prepress product, the film or the printing plate and the corresponding tone values in printing. Printing characteristics describe the extent to which a halftone image will get darker during printing due to dot gain. The curve is applicable to one press and depends on different parameters. The curve is determined by means of a stepped gray wedge, and much attention must be paid to such factors as paper grade, screen, printing ink, printing press, ink filling, dampening, and even room temperature and air humidity. |
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| Printing on demand |
| A process in which a few copies of a document are printed as needed, instead of a pre-defined, larger production run. Print on demand has been made possible by digital printing technology, which allows direct printing from prepress data, without having to produce printing forms or set up presses. |
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| Prism |
| In geometry a body with two parallel planes; in optics a body used to reflect light and generate a light spectrum. A prism is made of material that has a greater angle of refraction than its surrounding, which means that beams of light striking the short side of the prism vertically are totally reflected from the inside at the long side and exit at the second short side. |
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| Process calibration |
| See "standardization". |
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| Process color ink |
| One of the standard colors in four-color printing: cyan, magenta, yellow, black. |
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| Process fluctuation |
| Errors or instabilities in the CtP exposure unit or printing press that can result in unsightly mottling or striping. In the event that the optical density varies from copy to copy, such a fluctuation can immediately be seen when directly comparing printed products. |
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| Program paper |
| A flabby, generally woodfree paper made from chemical pulp derived from the soft leaves of hardwood trees. Allows noiseless page-turning. |
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| Progressive proofs |
| Proofs used to assess the colors on the printing stock. In four color printing, the four process colors cyan, magenta, yellow and black are printed both alone and in various combinations over a small area. |
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| Proof |
| A single print of a document which serves as a means of verifying proper text and layout. In analog proof procedures such as Dry-Match and Press-Match, the proof is created from ready imaged films, which accurately show the subsequent print product. In digital proofing, the page composed on the computer is output on a color printer. This proof is more cost-effective, as it does not require the use of film, though imaging procedures remain untested. |
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| Pulp |
| Cellulose fibers extracted from organic materials and used for the production of paper. |
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| PUR binding |
| A method of binding books and brochures using polyurethane adhesive, which is applied at a high temperature and hardens as it cools. PUR binding is a high-quality binding method, ideal for high-use products such as trade show catalogs and for difficult types of paper. |
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| Pure color |
| See "spectral color". |
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