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| Dampening system |
| The part of an offset press that draws a thin film of dampening solution-water with isopropyl alcohol and other additives–over the non-printing areas of the form. In vibrator-type dampening systems there is direct contact between the dampening solution container and a vibrator cylinder. In centrifugal, turbo or brush-type dampening systems there is no such direct contact. |
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| Data compression |
| Term used in information technology for the reduction of memory space required for data by optimizing the binary notation of the information. Depending on the nature of the original data and their coding, compression ratios of 1:100 and higher can be achieved. A distinction is made between compression methods that involve loss of information and "non-lossy" or lossless methods. Typical "lossy" methods include the JPEG format for images or the MP3 format for music clips. Methods for compressing numerical data, such as MNP5 and V.42bis for data transmission, and compression methods for files (zip, lha, rar, etc.), are of the lossless variety. |
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| Data mining |
| Term encompassing a range of processes used to glean information from databases. Data mining involves statistical and artificial intelligence methods and can reveal information about the typical behavior of groups of people. Data mining is a tool used, for example, by banks, insurance and other companies that collect large amounts of data on their customers. |
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| Database |
| An electronic filing system or organized system of information characterized by the use of data fields; can provide a foundation for procedures such as retrieving information, drawing conclusions, and making decisions. Traditional, computerized databases are organized by fields, records, and files. A field is a single piece of information; a record is a complete set of fields; and a file is a collection of records. |
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| Deep shadow |
| An area of an image not directly lit. There are two categories of shadows: umbra and penumbra. Umbra denotes completely shadowed areas and is formed when there is only one pointed light source, as a result of which the area behind the object is completely unlit. Penumbra refers to partially lit areas, when the light source is not pointed or when there is more than light source. |
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| Default |
| A computer software setting that states what will automatically happen in the event that the user does not state a preference. |
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| Deinking |
| A treatment to remove the printing ink from wastepaper so that the secondary fibers can be reprocessed. The deinking process makes it possible for higher-grade stocks to be manufactured from recyled content. The reprocessed pulp that results is known as DIP, or deinked pulp. |
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| Densitometer |
| An instrument used to measure the ink density of printed products and the degree of blackening of negative or positive films and bromides in photography. A densitometer can also be used to determine the density of profiles. Densitometers measure a color sample three times using three different color filters (red, green and blue filters), which are equivalent to the sensitivity of the three types of cones in the human eye, and densitometers are thus also referred to as three-filter reading devices. |
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| Densitometry |
| Densitometry is the quantitative measurement of ink density or the amount of ink per unit of area. It is used to determine tonal values, but not color hues. Densitometry can be used in photography and in reproduction for quality assurance purposes. |
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| Descender |
| Term used for the elements of a character that extend from the baseline (typeline) downwards to the p-line. In typography, descender denotes the extension of the characters g, q, p, y or j, which all contain lines that fall below the baseline. |
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| Design grid |
| An arrangement system consisting of horizontal and vertical lines in which all text blocks, images and pictures are contained, it is used to prevent the disorganized presentation of images, tables and other design elements. The definition of a design grid is part of the field of macrotypography. |
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| Device-independent color space |
| A reference color standard. Most color management systems use the LAB color histogram of the CIE (Commission Internationale d‘Eclairage) as the international color standard, independent of all devices. |
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| DFTA (Deutschsprachige Flexodruck Fachgruppe e.V.) |
| Created in the fall of 1979 and modeled after the FTA (Flexographic Technical Association), this association is based in Stuttgart and has over 400 members from the flexographic industry and scientific establishments. The association's goals include the technical advancement of flexographic printing, basic and advanced training, and the exchange of expertise and experience. The DFTA has a technology center at the Media College of Stuttgart Technical University. |
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| Dialog marketing |
| Refers to all company activities intended to directly address potential customers and elicit a response. Examples of dialog marketing include mailshots (personalized communications) containing various response options. The Internet is an ideal medium for dialog marketing. |
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| Didot point (dd) |
| Defined by the French printer François Ambroise Didot as exactly 0.376065 millimeters; the smallest unit of measure in the Didot measurement system. In 1879 the Didot point was rounded down to 0.376 millimeters, and in 1973 it was further rounded to 0.375 millimeters to facilitate conversions. |
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| Digital camera |
| A photographic camera that uses highly-integrated components (CCD chips) to convert the image captured by the lens into digital data, thus circumventing the need for film imaging, film development and scanning. |
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| Digital forme proofing |
| A hardcopy of computer data used to check for mistakes in text, layout, etc. |
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| Digital holography (synthetic holography) |
| Term used for the generation of images or illustrations in the form of interference patterns through computer calculations. Future applications for digital holography include high-capacity, long-term data storage devices based on plastic foil and ultra-small, forgery-proof markings for packaging, etc. |
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| Digital photography |
| Alternative to conventional photography, involves use of cameras that capture images directly in digital form. The image data is transferred by means of special storage media or a data interface to a computer for further processing. |
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| Digital printing |
| Refers to printing processes in which the information is transferred from the computer directly onto the paper, without the use of film or printing plates. Color printing technology is linked to the printing press' mechanical system. Though digital printing cannot deliver the same level of quality as conventional printing processes, it is faster and more cost-effective for small print runs and allows special techniques such as personalized printing and print-on-demand. |
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| Digital signatures |
| A type of "seal" created using a chip card and based on encryption software. Digital signatures are used in electronic communication to provide a legal alternative to the handwritten signature. These are ideal, for example, for electronic tax returns, home banking and electronic transactions. |
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| Digitization |
| The process of converting values into digital codes; the optical division of any original image into single pixels; the processing of data in a digitized electronic form of encoding. |
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| Dimensional stability |
| Measures how much a paper's dimensions change when its moisture is altered. This is a key criterion affecting a stock's suitability for multicolor offset printing. |
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| DIN (Deutsche Industrie Norm) |
| A system that defines concepts, measurements and application in the industrial sector. Certain DIN norms have been developed for offset print. |
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| DIN sizes |
| Standard metric sheet sizes widely used outside the United States. The most important ones belong to the A series, in which the next-smaller size has a length corresponding to half that of the next-larger size. They include A4 (210 x 297 mm) and A3 (297 x 410 mm).
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| Direct imaging |
| Refers to a new technology which uses PostScript data from the prepress stage to simultaneously image all the printing forms of a printing press with complete register accuracy. To do this the screen data supplied by a RIP (raster image processor) controls 64 infrared laser diodes, creating small recesses on a special printing foil with an ink-repellent surface, thus revealing an inking layer. The result is a printing foil which can be used for water-free offset printing. |
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| Discretionary hyphen (soft hyphen) |
| A hyphen placed within a word in order to divide it at the end of a line. The hyphen disappears if due to a change in the text flow, the word no longer falls at the end of a line. |
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| Dispersion coating |
| See "water-based coating". |
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| Display type |
| Type sizes used for titles, approximately 16 point or higher. |
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| Document management |
| Rules and measures applied to the creation, administration, distribution and archiving of documents. |
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| Document paper |
| Document paper is one of the highest grades of paper and bears a real watermark. The grade is generally used for official documents and certificates, and features special properties. |
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| Dot drop out |
| Refers to tonal values and the point up to which highlight dots are burnt out or are just available, expressed as a percentage of area coverage. The drop-out point of tone values can be determined by printing the related test wedges. |
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| Dot gain (dot growth, dot spread, press gain) |
| Term used in reproduction technology for the deviation in size of a previously calculated theoretical screen from the dot and screen actually printed, a phenomenon to be considered in order to ensure the quality of a printed product. This variation in dot size depends on several factors, including the printing method, substrate, printing ink, printing conditions and total ink limit. |
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| Dot matrix |
| A screen output device which make up character/images from a matrix of dots. The starting point for creating a raster is a dot matrix, which in newer RIP implementations consists of 128 x 128 elements. In this matrix, the dot shape is stored as a 12-bit gray tone. |
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| Dot spread (mechanical and optical) |
| See "dot gain". |
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| Dot touch |
| Contact made between two dots in the simulation of gray levels presented in halftone cells. With a square dot, dot touch will occur at a gray value of about 40 percent, with a round dot it will only occur at about 60 percent, and with an elliptical dot it will occur at 50 and 75 percent. With coarser screens, such as in laser printers, dot touch is less visible. |
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| Double |
| Term given to a word that has erroneously been typeset twice in a text. |
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| Double-sided printing |
| Printing of the front and back sides of a page with two different printing plates. |
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| Download |
| The process of transferring data from one computer or server to another; the transfer from one device to another in general; the specific process of loading fonts from a layout or graphical software program into the printer. |
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| Downstream |
| A kind of transmission by which information or data flows from a server to an end user. See “upstream”. |
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| Drag and drop |
| The process of moving text or images within a file or from one file to another. |
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| Drum scanner |
| A scanner that functions by mounting the original on a rotating cylinder, through or onto which a point-light is then transmitted. The scanning unit moves parallel to the cylinder’s axis of rotation, directing the light of the original via optical and color filters towards photo-multipliers. As photo multipliers only give analog signals, an electronic unit is required to convert them into digital signals. |
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| DTP (desktop publishing) |
| Refers to the combined processes of text creation, page makeup and image assembly as an integrated activity performed on the computer. DTP delivers data in the form of pages which are then further processed at the sheet assembly stage – either in the form of films or in electronic form (computer-to-film / computer-to-plate). DTP data uses the PostScript page description language. In electronic printing this data is used directly to produce print copies or for printing. |
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| Ductus |
| A typographic term used to describe the various elements of a character, such as the line, weight and direction in which each line is drawn. The term is derived from the Latin verb “ducere” (to lead), and was burrowed from calligraphy, where it is used to describe how the pen is held. |
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| Dummy |
| Sample of a print product which is designed to demonstrate such production features as format, page count, paper grade, finishing and binding. |
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| Dummy text |
| Term used for sample text, the purpose of which is to communicate the intended typographic impression of layouted pages or to reserve a space. Dummy text should be instantly recognizable as such - otherwise, as occasionally happens, it may erroneously be printed. |
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| Duplex board |
| A multi-layer carton with a gray intermediate ply, gray back and wood-free or almost wood-free coat on one side. |
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| Duplex images |
| Images used to enlarge the tonal value range of a grayscale image in print. A black/white reproduction, for example, can contain up to 256 grayscales. |
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