1.
Color scheme
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In color theory, a color scheme is the choice of colors used in design for a range of media. For example, the Achromatic use of a background with black text is an example of a basic. Color schemes are used to style and appeal. Colors that create a feeling when used together will commonly accompany each other in color schemes. A basic color scheme will use two colors that look appealing together, the addition of light blue creates an Accented Analogous color scheme. Color schemes can contain different Monochromatic shades of a color, for example. A color scheme in marketing is referred to as a dress and can be sometimes be copyrighted. Color schemes are described in terms of logical combinations of colors on a color wheel. Different types of schemes are used, Monochromatic colors are all the colors of a single hue. Monochromatic color schemes are derived from a single hue, and extended using its shades, tones and tints (that is. As a result, the energy is more subtle and peaceful due to a lack of contrast of hue. For the mixing of colored light, Newtons color wheel is used to describe complementary colors. Newton offered as a conjecture that colors exactly opposite one another on the hue circle cancel out each others hue, this concept was demonstrated more thoroughly in the 19th century. A key assumption in Newtons hue circle was that the fiery or maximum saturated hues are located on the circumference of the circle, while achromatic white is at the center. The split-complementary color scheme is a variation of the color scheme. In addition to the color, it uses the two Analogous colors adjacent to its complement. Split-complementary color scheme has the strong visual contrast as the complementary color scheme. Any color that lacks strong chromatic content is said to beunsaturated, achromatic, pure achromatic colors include black, white and all grays, near neutrals include browns, tans, pastels and darker colors
2.
User interface
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The user interface, in the industrial design field of human–computer interaction, is the space where interactions between humans and machines occur. Examples of this concept of user interfaces include the interactive aspects of computer operating systems, hand tools, heavy machinery operator controls. The design considerations applicable when creating user interfaces are related to or involve such disciplines as ergonomics and psychology. Generally, the goal of user interface design is to produce a user interface makes it easy, efficient. This generally means that the needs to provide minimal input to achieve the desired output. Other terms for user interface are man–machine interface and when the machine in question is a computer human–computer interface, the user interface or human–machine interface is the part of the machine that handles the human–machine interaction. Membrane switches, rubber keypads and touchscreens are examples of the part of the Human Machine Interface which we can see. In complex systems, the interface is typically computerized. The term human–computer interface refers to this kind of system, in the context of computing the term typically extends as well to the software dedicated to control the physical elements used for human-computer interaction. The engineering of the interfaces is enhanced by considering ergonomics. The corresponding disciplines are human factors engineering and usability engineering, which is part of systems engineering, tools used for incorporating human factors in the interface design are developed based on knowledge of computer science, such as computer graphics, operating systems, programming languages. Nowadays, we use the graphical user interface for human–machine interface on computers. There is a difference between a user interface and an interface or a human–machine interface. A human-machine interface is typically local to one machine or piece of equipment, an operator interface is the interface method by which multiple equipment that are linked by a host control system is accessed or controlled. The system may expose several user interfaces to serve different kinds of users, for example, a computerized library database might provide two user interfaces, one for library patrons and the other for library personnel. The user interface of a system, a vehicle or an industrial installation is sometimes referred to as the human–machine interface. HMI is a modification of the original term MMI, in practice, the abbreviation MMI is still frequently used although some may claim that MMI stands for something different now. Another abbreviation is HCI, but is commonly used for human–computer interaction
3.
Cathode ray tube
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The cathode ray tube is a vacuum tube that contains one or more electron guns and a phosphorescent screen, and is used to display images. It modulates, accelerates, and deflects electron beam onto the screen to create the images, the images may represent electrical waveforms, pictures, radar targets, or others. CRTs have also used as memory devices, in which case the visible light emitted from the fluorescent material is not intended to have significant meaning to a visual observer. In television sets and computer monitors, the front area of the tube is scanned repetitively and systematically in a fixed pattern called a raster. An image is produced by controlling the intensity of each of the three beams, one for each additive primary color with a video signal as a reference. A CRT is constructed from an envelope which is large, deep, fairly heavy. The interior of a CRT is evacuated to approximately 0.01 Pa to 133 nPa. evacuation being necessary to facilitate the flight of electrons from the gun to the tubes face. That it is evacuated makes handling an intact CRT potentially dangerous due to the risk of breaking the tube and causing a violent implosion that can hurl shards of glass at great velocity. As a matter of safety, the face is made of thick lead glass so as to be highly shatter-resistant and to block most X-ray emissions. Flat panel displays can also be made in large sizes, whereas 38 to 40 was about the largest size of a CRT television, flat panels are available in 60. Cathode rays were discovered by Johann Hittorf in 1869 in primitive Crookes tubes and he observed that some unknown rays were emitted from the cathode which could cast shadows on the glowing wall of the tube, indicating the rays were traveling in straight lines. In 1890, Arthur Schuster demonstrated cathode rays could be deflected by electric fields, the earliest version of the CRT was known as the Braun tube, invented by the German physicist Ferdinand Braun in 1897. It was a diode, a modification of the Crookes tube with a phosphor-coated screen. In 1907, Russian scientist Boris Rosing used a CRT in the end of an experimental video signal to form a picture. He managed to display simple geometric shapes onto the screen, which marked the first time that CRT technology was used for what is now known as television. The first cathode ray tube to use a hot cathode was developed by John B. Johnson and Harry Weiner Weinhart of Western Electric and it was named by inventor Vladimir K. Zworykin in 1929. RCA was granted a trademark for the term in 1932, it released the term to the public domain in 1950. The first commercially made electronic television sets with cathode ray tubes were manufactured by Telefunken in Germany in 1934, in oscilloscope CRTs, electrostatic deflection is used, rather than the magnetic deflection commonly used with television and other large CRTs
4.
Phosphor
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A phosphor, most generally, is a substance that exhibits the phenomenon of luminescence. Somewhat confusingly, this includes both phosphorescent materials, which show a slow decay in brightness, and fluorescent materials, where the emission decay takes place over tens of nanoseconds, Phosphors are often transition metal compounds or rare earth compounds of various types. The most common uses of phosphors are in CRT displays and fluorescent lights, CRT phosphors were standardized beginning around World War II and designated by the letter P followed by a number. Phosphorus, the element named for its light-emitting behavior, emits light due to chemiluminescence. A material can emit light either through incandescence, where all atoms radiate, or by luminescence, in inorganic phosphors, these inhomogeneities in the crystal structure are created usually by addition of a trace amount of dopants, impurities called activators. The wavelength emitted by the center is dependent on the atom itself. The scintillation process in inorganic materials is due to the band structure found in the crystals. An incoming particle can excite an electron from the band to either the conduction band or the exciton band. This leaves a hole behind, in the valence band. Impurities create electronic levels in the forbidden gap, the excitons are loosely bound electron-hole pairs that wander through the crystal lattice until they are captured as a whole by impurity centers. The latter then rapidly de-excite by emitting scintillation light, in case of inorganic scintillators, the activator impurities are typically chosen so that the emitted light is in the visible range or near-UV where photomultipliers are effective. The holes associated with electrons in the band are independent from the latter. Those holes and electrons are captured successively by impurity centers exciting certain metastable states not accessible to the excitons, the delayed de-excitation of those metastable impurity states, slowed down by reliance on the low-probability forbidden mechanism, again results in light emission. Many phosphors tend to lose efficiency gradually by several mechanisms, the degradation of electroluminescent devices depends on frequency of driving current, the luminance level, and temperature, moisture impairs phosphor lifetime very noticeably as well. Harder, high-melting, water-insoluble materials display lower tendency to lose luminescence under operation, examples, BaMgAl10O17, Eu2+, a plasma display phosphor, undergoes oxidation of the dopant during baking. Thin coating of aluminium phosphate or lanthanum phosphate is effective in creation a barrier layer blocking access of oxygen to the BAM phosphor, for the cost of reduction of phosphor efficiency. Addition of hydrogen, acting as an agent, to argon in the plasma displays significantly extends the lifetime of BAM, Eu2+ phosphor. Y2O3, Eu phosphors under electron bombardment in presence of oxygen form a non-phosphorescent layer on the surface, the traps also damage the crystal lattice
5.
Cathode ray
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Cathode rays are streams of electrons observed in vacuum tubes. They were first observed in 1869 by German physicist Johann Hittorf, electrons were discovered as the constituents of cathode rays. In 1897 British physicist J. J. Thomson showed the rays were composed of a previously unknown negatively charged particle, Cathode ray tubes use a focused beam of electrons deflected by electric or magnetic fields to create the image in a classic television set. Cathode rays are made up of charged particles. Cathode rays are so named because they are emitted by the electrode, or cathode. This contrasts with cations, which are charged and go — Greek ἰόν — toward a cathode in solution. To release electrons into the tube, they first must be detached from the atoms of the cathode, modern vacuum tubes use thermionic emission, in which the cathode is made of a thin wire filament which is heated by a separate electric current passing through it. The increased random heat motion of the filament knocks electrons out at the surface of the filament, since the electrons have a negative charge, they are repelled by the cathode and attracted to the anode. They travel in straight lines through the empty tube, the voltage applied between the electrodes accelerates these low mass particles to high velocities. Researchers noticed that objects placed in the tube in front of the cathode could cast a shadow on the glowing wall, and realized that something must be travelling in straight lines from the cathode. After the electrons reach the anode, they travel through the wire to the power supply and back to the cathode. The current in a beam of cathode rays through a tube can be controlled by passing it through a screen of wires to which a small voltage is applied. The electric field of the wires deflects some of the electrons, thus a small voltage on the grid can be made to control a much larger voltage on the anode. This is the used in vacuum tubes to amplify electrical signals. These are used in cathode ray tubes, found in televisions and computer monitors, after the 1654 invention of the vacuum pump by Otto von Guericke, physicists began to experiment with passing high voltage electricity through rarefied air. In 1705, it was noted that electrostatic generator sparks travel a distance through low pressure air than through atmospheric pressure air. In 1838, Michael Faraday passed a current through an air filled glass tube and noticed a strange light arc with its beginning at the cathode. In 1857, German physicist and glassblower Heinrich Geissler sucked even more air out with a pump, to a pressure of around 10−3 atm and found that, instead of an arc
6.
Monochrome
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Monochrome describes paintings, drawings, design, or photographs in one color or values of one color. A monochromatic object or image reflects colors in shades of limited colors or hues, images using only shades of grey are called grayscale or black-and-white. However, scientifically speaking, monochromatic light refers to light of a narrow band of wavelengths. In computing, monochrome has two meanings, it may mean having only one color which is either on or off, a monochrome computer display is able to display only a single color, often green, amber, red or white, and often also shades of that color. In film photography, monochrome is typically the use of black-and-white film, originally, all photography was done in monochrome. Although color photography was possible even in the late 19th century, easily used color films, if the red channel is eliminated and the green and blue combined then the effect will be similar to that of orthochromatic film or the use of a cyan filter on panchromatic film. The selection of weighting thus allows a range of artistic expression in the final monochromatic image. For production of an image the original color stereogram source may first be reduced to monochrome in order to simplify the rendering of the image. This is sometimes required in cases where an image would render in a confusing manner given the colors and patterns present in the source image. In physics, monochromatic light is electromagnetic radiation of a single frequency, even very controlled sources such as lasers operate in a range of frequencies. In practice, filtered light, diffraction grating separated light and laser light are all referred to as monochromatic. Often light sources can be compared and one be labeled as “more monochromatic”
7.
RGB color model
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The RGB color model is an additive color model in which red, green and blue light are added together in various ways to reproduce a broad array of colors. The name of the model comes from the initials of the three primary colors, red, green and blue. Before the electronic age, the RGB color model already had a theory behind it. Thus an RGB value does not define the same color across devices without some kind of color management, typical RGB input devices are color TV and video cameras, image scanners, video games, and digital cameras. Typical RGB output devices are TV sets of technologies, computer and mobile phone displays, video projectors, multicolor LED displays. Color printers, on the hand are not RGB devices. This article discusses concepts common to all the different color spaces that use the RGB color model, to form a color with RGB, three light beams must be superimposed. Each of the three beams is called a component of color, and each of them can have an arbitrary intensity, from fully off to fully on. The RGB color model is additive in the sense that the three beams are added together, and their light spectra add, wavelength for wavelength. This is essentially opposite to the color model that applies to paints, inks, dyes. When the intensities for all the components are the same, the result is a shade of gray, darker or lighter depending on the intensity. When the intensities are different, the result is a colorized hue, a secondary color is formed by the sum of two primary colors of equal intensity, cyan is green+blue, magenta is red+blue, and yellow is red+green. The RGB color model itself does not define what is meant by red, green and blue colorimetrically, and so the results of mixing them are not specified as absolute, but relative to the primary colors. When the exact chromaticities of the red, green and blue primaries are defined, the normal three kinds of light-sensitive photoreceptor cells in the human eye respond most to yellow, green, and violet light. As an example, suppose that light in the range of wavelengths enters the eye. Light of these wavelengths would activate both the medium and long wavelength cones of the retina, but not equally—the long-wavelength cells will respond more, the difference in the response can be detected by the brain, and this difference is the basis of our perception of orange. Thus, the appearance of an object results from light from the object entering our eye and stimulating the different cones simultaneously. The first experiments with RGB in early color photography were made in 1861 by Maxwell himself, to reproduce the color photograph, three matching projections over a screen in a dark room were necessary
8.
Teletext
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Teletext is a television information retrieval service created in the United Kingdom in the early 1970s by the Philips Lead Designer for VDUs, John Adams. It offers a range of text-based information, typically including news, weather, paged subtitle information is also transmitted within the television signal. It is closely linked to the PAL broadcast system used in Europe, other teletext systems have been developed to work with the SECAM and NTSC systems, but teletext failed to gain widespread acceptance in North America and other areas where NTSC is used. In contrast, teletext is nearly ubiquitous across Europe as well as other regions. Common teletext services include TV schedules, regularly updated current affairs and sport news, Teletext is broadcast in numbered pages. For example, a list of news headlines appear on page 110. The broadcaster constantly sends out pages in sequence, there will typically be a delay of a few seconds from requesting the page and it being broadcast and displayed, the time being entirely dependent in the number of pages being broadcast. More sophisticated receivers use a memory to store some or all of the teletext pages as they are broadcast. For this reason, some pages are broadcast more than once in each cycle, Teletext is also used for carrying special packets interpreted by TVs and video recorders, containing information about channels, programming, etc. Transmitting and displaying subtitles was relatively easy and it requires limited bandwidth, at a rate of perhaps a few words per second. However, it was found that by combining even a slow data rate with a memory, whole pages of information could be sent. In the early 1970s work was in progress in Britain to develop such a system, the goal was to provide UK rural homes with electronic hardware that could download pages of up-to-date news, reports, facts and figures targeting U. K. agriculture. The original idea was the brainchild of Philips Laboratories in 1970, in 1971, CAL engineer John Adams created a design and proposal for UK broadcasters. A major objective for Adams during the development stage was to make Teletext affordable to the home user. In reality, there was no scope to make an economic Teletext system with 1971 technology, however, as low cost was essential to the projects long term success, this obstacle had to be overcome. Meanwhile, the General Post Office, whose telecommunications division later became British Telecom, had been researching a similar concept since the late 1960s, unlike Teledata which was a one-way service carried in the existing TV signal, Viewdata was a two-way system using telephones. Since the Post Office owned the telephones, this was considered to be an excellent way to more customers to use the phones. In 1972 the BBC demonstrated their system, now known as Ceefax, the Independent Television Authority announced their own service in 1973, known as ORACLE
9.
WYSIWYG
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WYSIWYG is an acronym for what you see is what you get. WYSIWYG implies a user interface allows the user to view something very similar to the end result while the document is being created. In general, WYSIWYG implies the ability to manipulate the layout of a document without having to type or remember names of layout commands. The actual meaning depends on the perspective, e. g. WYSIWYG also describes ways to manipulate 3D models in stereo-chemistry, computer-aided design. Modern software does a job of optimizing the screen display for a particular type of output. For example, a processor is optimized for output to a typical printer. The software often emulates the resolution of the printer in order to get as close as possible to WYSIWYG, however, that is not the main attraction of WYSIWYG, which is the ability of the user to be able to visualize what they are producing. In many situations, the differences between what the user sees and what the user gets are unimportant. A preview mode, in which the attempts to present a representation that is as close to the final result as possible. Before the adoption of WYSIWYG techniques, text appeared in editors using the standard typeface. Users were required to enter special non-printing control codes to indicate that text should be in boldface, italics. In this environment there was little distinction between text editors and word processors. These applications typically used an arbitrary markup language to define the codes/tags, each program had its own special way to format a document, and it was a difficult and time-consuming process to change from one word processor to another. The use of tags and codes remains popular today in some applications due to their ability to store complex formatting information. When the tags are made visible in the editor, however, they occupy space in the text and so disrupt the desired layout. The Alto monitor was designed so that one page of text could be seen and then printed on the first laser printers. Bravo was released commercially and the software included in the Xerox Star can be seen as a direct descendant of it. The first release, named BRUNO, ran on the HP1000 minicomputer taking advantage of HPs first bitmapped computer terminal the HP2640, BRUNO was then ported to the HP-3000 and re-released as HP Draw
10.
Word processor
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A word processor is an electronic device or computer software application, that performs the task of composing, editing, formatting, and printing of documents. Later models introduced innovations such as spell-checking programs, and improved formatting options, as of 2009 there were only two U. S. companies, Classic and AlphaSmart, which still made them. Many older machines, however, remain in use, since 2009, Sentinel has offered a machine described as a word processor, but it is more accurately a highly specialised microcomputer used for accounting and publishing. Most are powerful systems consisting of one or more programs that can produce a combination of images, graphics and text, the latter handled with type-setting capability. In its simplest form, a processor is like an Expensive Typewriter or Typewriter machine, with the improvement of being able to proofread. Microsoft Word is the most widely used word processing software according to a tracking system built into the software. Microsoft estimates that half a billion people use the Microsoft Office suite. Many other word processing applications exist, including WordPerfect and open source applications OpenOffice. org Writer, LibreOffice Writer, AbiWord, KWord, web-based word processors, such as Office Online or Google Docs are a relatively new category. Word processors evolved dramatically once they became software programs rather than dedicated machines and they can usefully be distinguished from text editors, the category of software they evolved from. A text editor is a program that is used for typing, copying, pasting, text editors do not format lines or pages. Text editors are now used mainly by programmers, website designers, computer system administrators and they are also useful when fast startup times, small file sizes, editing speed, and simplicity of operation are valued, and when formatting is unimportant. Due to their use in managing complex software projects, text editors can sometimes provide better facilities for managing large writing projects than a word processor. Word processing added to the editor the ability to control type style and size, to manage lines, to format documents into pages. Functions now taken for granted were added incrementally, sometimes by purchase of independent providers of add-on programs, spell checking, grammar checking and mail merge were some of the most popular add-ons for early word processors. Word processors are capable of hyphenation, and the management. More advanced features found in recent word processors include, Collaborative editing, allowing users to work on the same document. Management, editing, and positioning of visual material, and sometimes sound files, automatically managed cross-references to pages or notes. Version control of a document, permitting reconstruction of its evolution, styles, which automate consistent formatting of text body, titles, subtitles, highlighted text, and so on
