1284 (IEEE 1284 parallel interface standard): the prevalent standard for connecting a computer to a printer or certain other devices over a parallel physical and electrical interface. The physical connection is similar to the older Centronics interface, which it continues to support. Whereas the Centronics interface only allowed data to flow in one direction, from computer to peripheral, IEEE 1284 also supports bi-directional data flow.
aliasing : the generation of a false (alias) frequency along with the correct one when doing frequency sampling. For images, this produces a jagged edge, or stair-step effect.
antialiasing : the smoothing of the image or sound roughness caused by aliasing. With images, approaches include adjusting pixel positions or setting pixel intensities so that there is a more gradual transition between the color of a line and the background color.
calibration : the setting or correcting of a measuring device or base level, usually by adjusting it to match or conform to a dependably known and unvarying measure.
Centronics parallel interface : an older and still widely-used standard I/O interface for connecting printers and certain other devices to computers. The interface typically includes a somewhat cumbersome cable and a 36-PIN male and female connector at the printer or other device. The cable plugs into a 25-pin parallel port on the computer. Data flows in one direction only, from the computer to the printer or other device. The prevalent standard, IEEE 1284, offers more speed and bi-directional communication.
coldset web offset printing (also known as non-heatset): a web offset printing process in which ink is allowed to dry naturally through evaporation and absorption. (See also heatset web offset printing .)
digital printing : the process of transferring a document on a personal computer or other digital storage device to a printing substrate by means of a device that accepts text and graphic output. Digital printing has steadily replaced lithography in many markets, especially at the consumer and business level, because of its substantially lower production costs.
DOT4 : a protocol that allows a component of a multifunction peripheral (MFP) to send and receive multiple data packets simultaneously across a single physical channel to other devices on the MFP. All data exchanges are independent of one another so cancelation of one does not affect the others.
dots per inch : the usual measure of printed image quality on the paper. The average personal computer printer today provides 300 dpi or 600 dpi. Choosing the higher print quality usually reduces the speed of printing each page.
electronic publishing on demand : the use of a digital printer to create a book. EPOD books often have relatively small print runs, even single copies, sometimes causing the method to be derisively referred to as vanity publishing.
EMF (Enhanced MetaFile): a spool file format used in printing by the Windows operating system. When a print job is sent to the printer, if it is already printing another file, the computer reads the new file and stores it, usually on the hard disk or in memory, for printing at a later time. Spooling allows multiple print jobs to be given to the printer at one time.
engraving : a method of creating raised areas of print or images on paper, such as a business card or letterhead. An impression is created on a metal plate, which is then filled with opaque ink. When paper is pressed into the plate, it creates raised and colored areas.
EPP/ECP (Enhanced Parallel Port/Enhanced Capability Port): a standard signaling method for bi-directional parallel communication between a computer and peripheral devices that offers the potential for much higher rates of data transfer than the original parallel signaling methods. ECP is for printers and scanners. EPP/ECP are part of IEEE Standard 1284.
flexography (sometimes referred to as "surface printing"): a method commonly used for printing on packaging and other uneven surfaces. In "flexo," the plates used in the printing process are often made of rubber or plastic, allowing the inked surface to conform to many kinds of substrates due to its flexibility.
Ghostscript : a program for Unix systems that interprets a Postscript file (which is a file formatted for a PostScript printer) so that, using a related program, Ghostview, you can view it on a display screen.
gravure : method in which an image is applied to a printing substrate by use of a metal plate mounted on a cylinder. Unlike other processes, gravure uses a depressed or sunken surface for the desired image. While gravure printing can produce high-quality results rapidly, the costs are significantly higher than other printing methods, including flexography or various forms of digital printing .
grayscale : a range of shades of gray without apparent color. The darkest possible shade is black, which is the total absence of transmitted or reflected light. The lightest possible shade is white, the total transmission or reflection of light at all visible wavelengths. Intermediate shades of gray are represented by equal brightness levels of the three primary colors (red, green and blue) for transmitted light, or equal amounts of the three primary pigments (cyan, magenta and yellow) for reflected light.
hard copy : printed copy of information from a computer. Sometimes referred to as a printout, a hard copy is so-called because it exists as a physical object. The same information, viewed on a computer display or sent as an e-mail attachment, is sometimes referred to as a soft copy .
imagesetter : a high resolution output device that can transfer electronic text and graphics directly to film, plates, or photo-sensitive paper. It can be thought of as a very expensive high resolution printer and can come in many different sizes and formats. An imagesetter uses a laser and a dedicated raster image processor (RIP) and is usually Postscript-compatible to create the film used in computer-based preproduction work.
inkjet printer : a printer that produces hard copy by spraying ink onto paper. A typical inkjet printer can produce copy with a resolution of at least 300 dots per inch (dpi). Some inkjet printers can make full color hard copies at 600 dpi or more. Inkjet printers are, as a rule, inexpensive.
landscape : a mode in which content is printed for reading on the longer length of the sheet of paper. This enables a longer than usual line length or image to be printable. The alternative is portrait mode, which is the usual default.
laser printer : a popular type of personal computer printer that uses a non-impact (keys don't strike the paper), photocopier technology. When a document is sent to the printer, a laser beam "draws" the document on a selenium-coated drum using electrical charges.
letterpress : the oldest form of printing, in which a surface with raised letters is inked and pressed to the surface of the printing substrate to reproduce an image in reverse. Examples of letterpress printing include carved wood or stone block printing.
LPT (line print terminal): the usual designation for a parallel port connection to a printer or other device on a personal computer. Most PCs come with one or two LPT connections designated as LPT1 and LPT2. Some systems support a third, LPT3. Whatever the number, LPT1 is the usual default.
multifunction peripheral (MFP): a device that performs a variety of functions that would otherwise be carried out by separate peripheral devices. As a rule, a multifunction peripheral includes at least two of the following: printer; scanner; copier; fax.
offset printing (also called offset lithography): a method of mass-production printing in which the images on metal plates are transferred (offset) to rubber blankets or rollers and then to the print media. The print media, usually paper, does not come into direct contact with the metal plates, which prolongs the life of the plates. The flexible rubber conforms readily to the print media surface, allowing the process to be used effectively on rough-surfaced media such as canvas, cloth or wood.
page description language (PDL): a language that specifies the arrangement of a printed page through commands from a computer that the printer carries out. Hewlett Packard's Printer Control Language (PCL) and Adobe's Postscript are the two most commonly used PDLs.
plotter : a printer that interprets commands from a computer to make line drawings on paper with one or more automated pens. Unlike a regular printer, the plotter can draw continuous point-to-point lines directly from vector graphics files or commands.
port replicator : an attachment for a notebook computer that allows a number of devices such as a printer, large monitor, and keyboard to be simultaneously connected. Each of the devices is attached to the port replicator and when the notebook user wants access to one or more of the devices, the user simply attaches the port replicator rather than having to connect one device at a time.
Portable Document Format (PDF): a file format that has captured all the elements of a printed document as an electronic image that you can view, navigate, print, or forward to someone else. PDF files are created using Adobe Acrobat, Acrobat Capture, or similar products.
portrait : a mode in which the printer orients content for reading across the shorter length (the width) of the sheet of paper. Because most printing is done in portrait mode, it is set up as the default mode for printer operation. The alternative to portrait mode is landscape mode, which presents content across the longer length of the sheet of paper.
Postscript : a programming language that describes the appearance of a printed page. It was developed by Adobe in 1985 and has become an industry standard for printing and imaging. All major printer manufacturers make printers that contain or can be loaded with Postscript software, which also runs on all major operating system platforms.
PPD file (Postscript Printer Description) file: a file that describes the fonts, paper sizes, resolution, and other capabilities that are standard for a particular Postscript printer.
printer : a device that accepts text and graphic output from a computer and transfers the information to paper, usually to standard size sheets of paper. Printers vary in size, speed, sophistication, and cost. In general, more expensive printers are used for higher-resolution color printing.
Printer Control Language (PCL): a language that enables applications to control Hewlett-Packard DeskJet, LaserJet, and other HP printers.
scanner : a device that captures images from photographic prints, posters, magazine pages, and similar sources for computer editing and display. Scanners come in hand-held, feed-in and flatbed types and for scanning black-and-white only, or color.
screen printing (also known as serigraphy): a method of creating an image on paper, fabric or some other object by pressing ink through a screen with areas blocked off by a stencil.
sheet-fed offset printing : method in which individual pages of paper are fed into the machine. This printing method is popular for small and medium-sized fixed jobs such as limited-edition books. In another method, web offset printing , a continuous roll of paper is fed through the printing press.
spool (simultaneous peripheral operations online): a computer document or task list is to read it in and store it, usually on a hard disk or larger storage medium so that it can be printed or otherwise processed at a more convenient time
substrate :a solid substance or medium to which another substance is applied and to which that second substance adheres. In offset printing, the substrate the material onto which the print ink is ultimately applied, such as paper, canvas or cloth.
thermal transfer printing : a type of thermographic printing in which heat is used to transfer print from a ribbon to paper.
thermographic printing : an application of thermography in which heat is used to create images on paper. There are two types of thermographic printing. In thermal printing, paper is coated with a heat-sensitive substance. In thermal ink transfer printing, heat is used to transfer print from a ribbon to paper.
thermography : a printing or imaging method that uses heat in the process. The printing method, known as thermographic printing, uses heat to create an image.
Universal Plug and Play :a standard that uses Internet and Web protocols to enable devices such as PCs, peripherals, intelligent appliances and wireless devices to be plugged into a network and automatically know about each other.
web offset printing : a form of offset printing in which a continuous roll of paper is fed through the printing press. Pages are separated and cut to size after they have been printed. Web offset printing is used for high-volume publications such as mass-market books, magazines, newspapers, catalogs and brochures.
WYSIWYG : describes a program that allows the user to see what the end result will look like while an application, image or document is being created. WYSIWYG is an acronym for "what you see is what you get."
xerography :a printing and photocopying technique that works on the basis of electrostatic charges. The xerography process is the dominant method of reproducing images and printing computer data and is used in photocopiers, laser printers and fax machines.
Xon/Xoff :a protocol for controlling the flow of data between computers and other devices on an asynchronous serial connection.