'endash' - a dash ( <2013> ) equal or approximately equal to the width of an
'figuredash' - a dash ( <2012> ) equal to the average width of « Arabic » numerals (<0030> to <0039>) in a particular typeface.
'quotedash' - a dash ( <2015> ) slightly longer than the 'emdash' and used to isolate quoted text.
These four dashes are available in most Production First Software typefaces having a complete complement of Roman (Latin) character glyphs. Also see hyphen and soft hyphen.
data binding A process whereby a data cache is embedded in a Web page using a data source object (DSO) placed within HTML or XML. The data cache can link or bind (from within the DSO) to additional data sources over an intranet or the Internet.
data mining Refers to an information retrieval technique which searches databases for patterns of information rather than for specific labels or tags.
Da Yi An input method which determines a Han character based on 40 basic radicals arranged on a standard keyboard. The selection order is based on the order in which strokes in a Han ideograph are usually written on paper.
DBCS An abbreviation for Double Byte Character Set. The term is usually applied to a modal font which uses both 1-byte and 2-byte characters, or to a mixed encoding.
DCF An abbreviation for Digital Camera Format. A data file format used for digital camera images when writing to CompactFlash, diskette, or SmartMedia storage media.
DCOM An acronym for Distributed Component Object Model Architecture, a client/server communication protocall used in middleware, architected by Microsoft. A competing protocall is CORBA, an international standard.
DCS or .DCS file An abreviation for Desktop Color Separation format, developed by Quark and Agfa. It is an extension of the EPS format, except that the separation data is apportioned into several files, rather than only one file. There are 5 or more files in each set: a low resolution full color master file, and individual high resolution files for each process or spot color. The digital workflow software then integrates the usage of all the files.
.DCX file See bitmap formats.
DDL A page description language developed by Imagen.
DDoS Abbreviation for Distributed Denial of Service. A situation when a Website or server is overloaded and disabled by a large number of data packets sent to it over a short period of time. When done deliberately (as it most often is), it is called a DDoS attack.
dead key A key which performs a function but does not advance the current position on a line being typed.
decompose To replace a single object with two or more component objects, the collection of components behaving equivalently to the single object after possibly being subject to adjustment. [N.B. A dictionary definition uses the words « separate ... into » instead of « replace ... with. »]
decomposable character See composite character.
decorative A typeface style generally not suitable for text body copy, and which usually incorporates one or more of the following criteria: design features of several style categories; extremes in weight (very thin or very heavy); highly unusual in design; low-legibility due to abstract, complicated, or fancy design; and including glyph designs other than from a standard alphabet script (for example, embellishments). The following subcategories have been defined:
:Ornamental - Particularly ornate or highly decorated designs. Typeface examples include: Flirt, Fry's Ornamented, Nymphic.
:Outrageous - Unusual or avant-garde highly-stylized humorous, satirical, whimsical, or otherwise unclassifiable designs. Typeface examples include: Calypso, ITC Aki Lines, Litzenburgh, Shatter.
:Sans Serif - Without serifs. Typeface examples include: Neon, Palou, Pinball, Stack, Streamline, Zip.
:Script - Imitating characteristics of the style of handwriting. Typeface examples include: Bernard Tango, Blado Italic, Commercial Script, Dom Casual, Park Avenue.
:Serif - Having serifs. Typeface examples include: Antikva Margaret, Fantail, Fournier, Pierrot, Skyjald.
decryption The process by which an unrecognizable sequence of characters is translated into a sequence of recognizable ASCII text characters using a formula or algorithm.
Deep Computing and Deep Computing Institute A term and initiative coined by IBM for describing its latest development of supercomputing hardware. This ranged from the IBM 650 through the IBM 7094-Stretch through the IBM 360/91 through the IBM 360/195 through the IBM 3081 through the IBM RS/6000 SP (which won the chess match with Gary Kasparov).
delta hinting A technique used in TrueType fonts which alters hinting instructions for bitmaps generated at certain point sizes and display resolutions by adding additional instructions. The technique is not applicable in PostScript, because PostScript interpreters handle hinting in a different manner.
Delta hinting makes bitmap on-screen displays of character glyphs look better on screen, at the expense of distorting the design of the actual glyph shape. Alternatives to delta hinting include the placement of embedded bitmaps in the font, providing separate bitmap screen fonts for certain pointsizes and display resolutions (applicable to PostScript fonts as well), and altering the designs of the glyph shapes so that they inherently appear clearer at commonly used display resolutions (also applicable to PostScript fonts, but using different design alterations than with TrueType fonts). The biggest dilemma with delta hints is that TrueType fonts can be installed on systems having a variety of display resolutions, and each combination of point size and display resolution must be anticipated.
Production First Software makes use of all the techniques listed above, with specific techniques applied to specific typefaces and font formats. However, the construction and size of « big fonts » dictates that these extra delta hint instructions be used judiciously, so as not to bloat the size of the font.
demand publishing The publishing of single documents, single copies of a document, or small numbers of copies, upon requirement.
dentation Alteration of the edges of a digital image so as to improve blending with the background.
descendant font A font which is specified, pointed to, or used by another font.
descender A character stem which descends below the baseline without being reconnected to a portion of the character above the baseline.
descender line or descent line A line parallel to the baseline at the end of the descenders.
Deseret Alphabet Named after a term from the Book of Mormon, it is an English language alphabet developed c1853 for The Church of Jesus Christ of Latter-day Saints. The purpose of the Deseret Alphabet was to provide simplified, easier spelling of English words. Theoretically, it is not a phonetic alphabet, because each letter does not really represent all specific phonetic elements or sounds used for English.
design axis An adjustable attribute of a MultipleMaster, Type 1 GX, or TrueType GX font. The usual design axes are: Weight, Width, Optical Size, and Style. Other axes could be: Density (for nicks or traps), Ligatures, x-Height, Extenders, Outline Texture, etc.
desktop publishing The technology used to produce publications (advertisements, banners, flyers, letters, magazines, newsletters, signs, etc.) using desktop hardware (computer workstations, scanners, printers, etc.) and software which runs on it.
Deutsch Fraktur See Dfr.
device Same meaning as « output device. »
device font Microsoft terminology for a font which is designed to be used for or downloaded to a specific output device, usually a printer or plotter.
Dfr Refers to a specialized (but non-standardized) character set used for DeutschFraktur or black letter typefaces.
DHTML An abbreviation for Dynamic HTML.
diacritic or diacrit See diacritical mark.
diacritical mark or diacritical A token, symbol, or other notation which can be represented as a base character and serves to distinguish a character or modify the pronunciation of a character or series of characters when associated with a base character. A diacritical mark assembles with or combines with another base character to produce a composite character.
.DIB file See bitmap formats.
Didone See Modern.
didot or didot point A unit of measurement refered to as the didot point, and abbreviated « ptD. » or « dd. » 1 ptD = 0.014800 inch or 0.37592 mm.
dieresis or diæresis A diacritical mark ( ¨ ) optionally used in English, oftentimes replaced by a hyphen. In English, the dieresis is used on a second identical vowel to indicate a change in pronunciation of that vowel or indicate it is pronounced in a separate syllable. It is sometimes referred to as an « umlaut » when used with a single character or in a « diphthong. » Examples: reëlecting, reëncoding, coöperation, coördination.
digital certificate A standardized packet of encrypted data used to authenticate that a document has been created by a certain entity. The digital certificate may also include a digital signature.
digital envelope See digital signature.
digital press See digital printing.
digital printing A printing device, usually color, which can be driven directly from a computer like any other output device. Currently, two types of digital presses are in use. The first to be developed was a conventional multi-head offset web press, modified by adding a RIP and then directing the output of the RIP so that each color image component is automatically transfered to a drum in each head which serves as the plate for that color. A later type of digital press does not use web offset technology, but rather an electromechanical process somewhat related to xerography but using mechanically-deposited ink rather than dry toner. The advantages and disadvantages of both technologies are summarized in the table below. An asterisk (*) is used if a capability or feature is available.
#1 #2 Feature or Capability
* color graduations accomodated satisfactorily
* dot gain minimized
* folds can be any orientation
* large areas of solid colors or grays represented satisfactorily
* printed image tends to crack where folded
* run-to-run color repeatability without frequent recalibration
* undercolor removal recommended
* variety of halftone screens accomodated successfully
* wide range of special inks, including metallics and varnishes
* wide variety of paper, cardboard, or fabric for the medium
digital proofer A color printer with technology suitable to produce a hard color copy sufficiently close to what would be produced by conventional offset printing. Color printing technologies currently being used for digital proofing include color laser, dye-sublimation, electrostatic, high resolution inkjet, and thermal wax transfer.
The proofing technology chosen should ideally be capable of high resolution imaging (1000 to 4000 dpi); be able to reproduce the same halftoning representation for each color as in the separation negative made for the corresponding offset press plate; have the same RIP characteristics; possess the same dot gain and coverage saturation as the offset press for each color; and be capable of printing on the same media stock as would be used in the offset press. All of these characteristics are necessary for accurate proofing, in order to check for problems like inconsistent image rendering, moiré effects, ink saturation problems, and text representation. Most of the technologies are lacking in one or more of these ideal requirements; therefore, they are not entirely trustworthy for critical proofing.
Conventional color offset printing uses multi-head presses, each head using a separately prepared plate, printing a different process or spot color. The individual plates are usually prepared by first producing color separation negatives from an imagesetter, and then making the plates. Before digital proofing, separation negatives were used to construct a proof photographically (« color key, » « Cromalyn, » « Matchprint, » etc.) or using an actual short press run ( « press proof »). With digital proofing, it possible to either make plates directly using a platesetter; or skip the plate-making step entirely and output directly to a digital press; because negatives are not necessary for producing a proof.
digital signature A standardized procedure which indicates to the reader whether or not a message has been altered and that the originator of the message is authentic. The message may be sent either as plaintext, or the message can be encrypted. If the message is encrypted, the encryption is termed a « digital envelope. »
A digital signature is actually implemented by making use of Public Key Infrastructure or PKI. This uses a pair of encrypted keys, one of which (the public key) is openly known and is used to authenticate an encrypted key which is embedded in a "signed" document. This process produces a digital certificate which is added to the document or software and having a derivable "hash" value valid only for the original document. Whether a document has been altered by other than the originator can be determined by deriving its hash value and comparing it to the document's original equivalent derivable hash value, which would no longer match the original hash value stored in the digital certificate. Authentification of the digital signature occurs when the public key matches the embedded key. A private key, which is kept secret by the originator, is used to create the embedded key. The keys are supplied to an originator upon application to security providers, such as Entrust, UserTrust, or Verisign for a periodic fee. If a renewal fee is not paid, the digital certificate expires and a document signature created using that certificate is no longer valid. An operating system (like Windows2000 OR WindowsXP) which has built-in certificating authority (records of all valid digital certificates) will no longer validate documents or software whose digital certificates expired.
Unfortunately, the concept of the digital signature has been turned into a political football and lucrative profiteering device by Microsoft and other coöaut;perating companies (such as Verisign), particularly victomizing small software developers. In order to get a hardware or software product into the Microsoft Windows Catalog, the product must be registered online with Microsoft. This usually necessitates purchasing three expensive hardware PCI-SIG cards at US$1000 each (for registering hardware or drivers), plus US$250 per operating system plus US$100 per listing after the first one after the qualification round, and then paying US$400 per year per product for keeping the digital certificate valid.
Digital Style A typeface structural style comprised of segmented strokes simulating the appearance of liquid crystal or fluorescent gas tube displays.
digital subscriber line See DSL.
digital text corpus A document which contains text in a script no longer in use.
digital type The now obsolete computer technology and data protocall previously used in computerized typesetting. It was a non-standardized technology which required a specially designed minicomputer system with proprietary font formats and largely bitmapped character images. Every type vendor has its own, sometimes proprietary, format.
digital watermark A watermark added to a digital sound track or graphic image for the purpose of authentification and identification. The watermark is usually added to a critical sound byte or portion of an image using a software utility; and it is nearly inaudible or invisible to the unaided eye.
Unfortunately, digital watermarking is doomed by its very nature, as well by other technology. For example, for every copy protection scheme invented, a work-around has always been identified or developed. Digital data lossy compression schemes also can distroy some digital watermarks which are not sufficiently robust. And since new compression schemes are being developed constantly, there is no way to insure that a digital watermark will always be robust enough.
digital workflow The transference and processing of data files representing digitally-constructed tasks on a client or network.
An example could be the following: the creation of graphics (using, say, Adobe PhotoShop), and the creation of text files (using, say, Microsoft Word) which may then be combined to become part of an advertisement (using, say, Adobe PageMaker), or a Web homepage (using, say, SoftQuad HotMetal Pro), and then turned into an electronic document (using, say, Adobe Acrobat Distiller) in preparation for printing.
digitize To convert an image into data that can be stored in a digital computer. It is usually applied to data represented as bitmap data, rather than as object-oriented or vector-based data.
digraph A combination of two letters which represent a single phonetic or sound, but are manipulated as a single letter or element in spelling (and, therefore, assignable to a single character).
dingbat A miscellaneous decorative, pi character, or symbol glyph sometimes used as a marker or for a different purpose than originally intended. For example, a silhouette of an airplane, used to indicate an airport on a map, or placed next to the name of a city in a list to indicate air service.
diphthong Two adjacent vowels in a word syllable whose sound is a continual change from the sound of the first to the sound of the second. Some diphthongs (like ae) can be represented by ligatures (like æ).
direct encoding model A model of encoding which maps every required glyph to a different code point. Glyphs encoded could include form variants (such as initial, medial, final, and isolate) commonly used in Arabic and Indic scripts and less commonly used in Greek and Latin; style variants used in the same language or script (monetary symbols, for example); and language-related style variants (such as Chinese and Japanese style variants for the same Han character).
The use of the direct encoding model has the following disadvantages:
(1) The encoding space required is increased.
(2) Text can no longer remain « plain » but includes elements representing variants which may not be displayable if the proper font resource or rendering technology is not available.
The use of the direct encoding model has the following advantages:
(1) A requirement for a contextual processing mechanism is eliminated.
(2) Applications which do not include any mechanisms for variant selection can still access variants.
(3) An encoding becomes font format-agnostic.
directionality A property of characters and scripts which denotes the normal writing direction. The directionality property usually only distinguishes left-to-right (most American Indian alphabets, Armenian, Cyrillic alphabets, Ethiopian, Georgian, Greek, Indic scripts, Roman alphabets) and right-to-left (Arabic-related, Hebrew) writing directions, even though some writing systems such as Egyptian hieroglyphics, are written in both directions; ideographic scripts are written either horizontally or vertically; Tibetan is written only vertically; and text characters in some American Indian and South Asian Indic scripts are written left-to-right but stack vertically (quad-directionality).
direct imaging A press technology which uses a fixed image carrier (plate) with the image electronically transferred to the image carrier, the printing taking place, and then the image carrier and rendering system cleaned and prepared for the next image.
direct-to-plate See direct imaging.
disabled user See print legibility for the visually-impaired and Unified Web Site Accessibility Guidelines.
display cell In terms of a monospaced font, the smallest pixel array space allocated for each character glyph. It is constrained in width by the (monospaced) character width, and in height by the font bounding box. In fonts supporting CJK, there are usually two character widths associated with a monospaced font: half-width, and full-width characters. The half-width characters consist of all non-Han characters and some half-width Han characters. The remaining Han characters are full-width and twice as wide as the monospace character width. In proportional fonts, each character width can be different, so that the width of the display cell of each character glyph may be different.
displayed formulas Mathematical equations interspersed within lines of text or between text blocks.
display list and display list processing A list of reorganized and codified PostScript instructions for rendering a page, produced internally by a PostScript raster image processor and stored on an internal disk. Display list processing is used almost exclusively by very high resolution output devices, where processing and printing a page might take a relatively long time, especially if halftone screens are required on the page. The purpose of creating such a list is to be able to more efficiently output the page, combine several pages sequentially of perhaps several jobs so as to minimize the amount of photographic film or paper used, or be able to output the page again in the event of a mechanical jam. Usually, only film recorders or imagesetters use internal display list processing. Most PostScript output devices, using media other than film, process PostScript on-the-fly without any intermediate steps other than using multiple passes.
display PostScript or Display PostScript A form of PostScript whose purpose is to display on a computer monitor screen instead of generating hard copy output on a laser printer, imagesetter, or film recorder. Display PostScript, some day, will render the use of screen fonts and bitmaps unnecessary for screen imaging.
display type Type larger than a type size of 14 points.
display typeface A typeface designed to be used larger than 14 points. Sometimes, display typefaces have only a small character set, consisting of only basic upper and lower case letterforms.
distressed font Another term for « grunge font. » However, the use of the word « distressed » is a misnomer much of the time; because the term « distressed » specifically refers to irregular coloration only, and not to irregularities of shape and size (which are the usual hallmarks of grunge fonts). A letterform may be distressed without having come from a grunge font.
distributed computing system An architecture with several levels of computing: client, dispatch server (accessed by the client through the World Wide Web), application servers, and database servers. The client/dispatch server interconnection is through the Internet, whereas the interconnections between the dispatch server and the other levels of computing are through an intranet.
distributed file system A file system proposed by Microsoft which manages files homogeneously across distributed computing systems.
dithering A process used in output devices (monitor screens or some hardcopy printers) to produce shades of gray or tints of colors. The dithering process places dots on the media at precalculated locations in a pseudo-random fashion by a software algorithm so as to visually reproduce the desired effect. The computer algorithm is built into the printing interfaces of most operating systems, and sometimes it is built into printer description language software (such as HPGL).
DjVu A format originally developed by AT&T which produces a optimally-compressed single image file capable of incorporating both text and graphics. The graphics are compressed using a format similar to JPEG images, while the text portions are compressed by storing one bitmap copy of each unique letterform and composing the text using pointers. The text and graphics are then combined into one file. DjVu files are 30% smaller on average than equivalent PDF files containing text and graphics and at least 80 to 90% smaller than other bitmap-only image formats.
Display of DjVu files requires a browser plugin viewer, available (free) from LizardTech of Seattle, along with a utility (by license) for creating DjVu files.
DNA computing or DNA computer A simplification of molecular computing, only functioning in a test tube and programmed to perform only a specific task.
Document Type Definition or DTD An element (usually in a .DTD file) which defines tags, elements, and other structures used within an HTML or XML document file. A DTD call is usually placed at or near the beginning of a markup language file. A DTD is necessary for XML to define structures, without which XML cannot function. For example, if an HTML file is to work in all XML parsers, there must be a DTD call placed in the HTML file, although some XML parsers may recognise the HTML file without it.
Eventually, XML schema will replace the use of DTD elements in XML. DTD features are a subset of XML schema features.
DOD 5015.2 A U.S. Dept. of Defense standard called the Design Criteria Standard for Electronic Records Management. A standard used to approve all document and records management software. It addresses freedom of information, privacy, security of classified records, and other handling issues for the whole lifecycle of a document (from creation to disposal).
DOM An acronym for Document Object Model.
domain name See top level domain name.
domain name category See top level domain level category.
domain name system or DNS A system used by the Internet for locating and identifying Internet addresses. It may be supplanted and eclipsed in the future by the use of keywords and directory services.
dot gain The increase in the size of printed halftone dots due to the imperfect and imprecise process of producing a plate from a film, metering printing ink onto a press blanket, and transferring the ink from the blanket to a medium (usually paper).
Dot gain can be compensated for in modern electronic publishing procedures. This is most easily accomplished by modifying and activating a PostScript « transfer function, » which is a table which maps the true grayscale value with a corrected grayscale value. The corrected grayscale values are those which will produce the correct grayscale values on the medium after being subject to the printing process. This is done either for 256 values of gray (PostScript Level 1 or 2) or for 4096 values of gray (PostScript 3). The transfer function is introduced into the PostScript RIP (either through the job page description, by preload, or by selecting a transfer function already built-in) prior to the generation of job film by an output device.
Dot gain can also be compensated for, to a lesser degree, by altering the shape of the halftone marks. Instead of using circular dots, ellipsoids, diamonds, rectangles, or propellers may also be used, or a combination, depending on the dot size and frequency. A second-order stochastic screening technique can also reduce dot gain.
Double Byte Character Set (DBCS) A character set whose encoding must contain both 1-byte and 2-byte characters. Examples include JIS and Shift-JIS character sets.
double ligature A ligature composed of more than two connected characters. Double ligatures are not usually found in typical fonts. They are usually found only in expert sets. All Production First Software fonts include double ligatures when appropriate for the typeface design. They are included, not in expert sets, but rather as « special characters, » within a Presentation Form Unicode block, or in descendant fonts.
double-storey or double storey See two-storey.
doublestruck A typeface or letterform structural style having letterforms composed of some vertical outlined strokes combined with solid horizontal strokes. The name derives from the original practice on a typewriter of double striking with manually offsetting the carriage between strikes. The style is used in typesetting some mathematical quantities in equations. Doublestruck style is not correctly identified as inline or outline, even though it is sometimes characterized as such.
douze Same as cicero. A unit of measurement: 1 douze = 12 didot points.
downloadable font Literally, any installable font which must be downloaded to an output device for use. The Microsoft terminology for this is « device font.
downloading The process of loading a font or PostScript program into the output device's computer memory or onto its hard disk.
DPOF An abbreviation for Digital Print Order Form. A data format for information regarding how a digital image is to be printed. This information is sometimes included on the same electronic medium as the image it pertains to, so that the image is printed in accordance with the DPOF data.
Dr. Halo file format A dual-file (.CUT and .PAL files) image format developed by Media Cybernetics primarily for advanced image scientific applications. Monochrome images do not need the .PAL file.
drop cap
drop folio A page number placed at the bottom of the page when page numbers are placed at the top of other pages. Drop folios would be used, for example, on a title page, first page of a chapter, index pages, and table of content pages.
DRM An abbreviation for Digital Rights Management, software which controls the type of access to other software based on patent and copyright rights. A preliminary concept capability of this (permission-based usage) has been built into TrueType and OpenType fonts since 1996, but DRM is aimed mainly at protecting intellectual rights of audio and video software. A method for achieving intellectual rights protection in PostScript fonts is poisoning.
drop shadow A slightly offset duplication of a letterform or string of type using the same typeface, usually halftoned.
dry transfer lettering Letterforms, symbols, or other character glyphs which are printed on the back of a waxed, nearly transparent, transfer sheet. They can be transferred to another medium by pressing or rubbing the sheet placed on top of the medium. Dry transfer lettering is widely used in kitchen table publishing, layout composing, and model building.
DSL An abbreviation for Digital Subscriber Line. See ADSL, HDSL, SDSL, and VDSL.
DSO An abbreviation for Data Source Object. See data binding.
DSP See display PostScript.
DTI An abbreviation for Digital Video Interface. A digital interconnect standard developed by the Digital Display Working Group for connecting flat panel displays (for example LCD or TFT) or analog display devices with a digital interconnect interface.
DTP See desktop publishing.
Dublin Core metadata set A low overhead metadata format which is the standard for OAI and OLAC.
ducking A reduction of cap height or x-height for letterforms having diacritical marks so that the total height is no greater than the cap height + overshoot for letterforms without diacritical marks.
ductility The property of a typeface, having a script structural style with joined strokes, to squeeze or stretch in text by adjusting the connecting strokes. This can be implemented in several ways: by the use of a kashida between characters, or by the use of a font format which has the inherent capability (such as PostScript MultipleMaster, PostScript GX, or TrueType GX ).
ductility index or DI A ductility property index formulated by Production First Software to compare the ability of ductile typeface designs to be stretched. The higher the ductility index, the more practical the typeface design is for stretching. The ductility index is defined as:
where the stroke thicknesses are typical or average lowercase stroke thicknesses and the sum is taken over 26 UPPERCASE and 26 lowercase basic Latin alphabet letterforms.
Dutch Old Style or Dutch-English Old Style See Old Style.
dynamic HTML A marketing term given to HTML which is generated by a software program in response to an action, query, or link, and then is acted upon. The software program may be contained in a Java applet on a client, in a JavaScript scriptlet from inside a Web document, or from a Java servlet on a server. The operation of this Encyclopaedia of Typography and Electronic Communication was made possible by using dynamic HTML.
dynamic range A term referring to the entire range of adjustment of a design axis in a MultipleMaster PostScript font.
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