1.
Lithography
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Lithography is a method of printing originally based on the immiscibility of oil and water. The printing is from a stone or a plate with a smooth surface. It was invented in 1796 by German author and actor Alois Senefelder as a method of publishing theatrical works. Lithography can be used to print text or artwork onto paper or other suitable material, Lithography originally used an image drawn with oil, fat, or wax onto the surface of a smooth, level lithographic limestone plate. The stone was treated with a mixture of acid and gum arabic, when the stone was subsequently moistened, these etched areas retained water, an oil-based ink could then be applied and would be repelled by the water, sticking only to the original drawing. The ink would finally be transferred to a paper sheet. This traditional technique is used in some fine art printmaking applications. In modern lithography, the image is made of a coating applied to a flexible aluminum plate. The image can be printed directly from the plate, or it can be offset, by transferring the image onto a sheet for printing. In fact, photolithography is used synonymously with offset printing, the technique as well as the term were introduced in Europe in the 1850s. Beginning in the 1960s, photolithography has played an important role in the fabrication, Lithography uses simple chemical processes to create an image. For instance, the part of an image is a water-repelling substance. Thus, when the plate is introduced to a printing ink and water mixture, the ink will adhere to the positive image. This allows a flat print plate to be used, enabling much longer, Lithography was invented by Alois Senefelder in the Kingdom of Bavaria in 1796. In the early days of lithography, a piece of limestone was used. After the oil-based image was put on the surface, a solution of gum arabic in water was applied, during printing, water adhered to the gum arabic surfaces and was repelled by the oily parts, while the oily ink used for printing did the opposite. Lithography works because of the repulsion of oil and water. The image is drawn on the surface of the print plate with a fat or oil-based medium such as a wax crayon, which may be pigmented to make the drawing visible
2.
Halftone
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Halftone is the reprographic technique that simulates continuous tone imagery through the use of dots, varying either in size or in spacing, thus generating a gradient-like effect. Halftone can also be used to specifically to the image that is produced by this process. This reproduction relies on an optical illusion, the tiny halftone dots are blended into smooth tones by the human eye. At a microscopic level, developed black-and-white photographic film also consists of two colors, and not an infinite range of continuous tones. The semi-opaque property of ink allows halftone dots of different colors to create another optical effect—full-color imagery, william Fox Talbot is credited with the idea of halftone printing. In a 1852 patent he suggested using photographic screens or veils in connection with an intaglio process. Several different kinds of screens were proposed during the following decades, one of the well known attempts was by Stephen H. Horgan while working for the New York Daily Graphic. The first printed photograph was an image of Steinway Hall in Manhattan published on December 2,1873, the Graphic then published the first reproduction of a photograph with a full tonal range in a newspaper on March 4,1880 with a crude halftone screen. The first truly successful commercial method was patented by Frederic Ives of Philadelphia in 1881, although he found a way of breaking up the image into dots of varying sizes, he did not make use of a screen. In 1882, the German Georg Meisenbach patented a process in England. His invention was based on the ideas of Berchtold and Swan. He used single lined screens which were turned during exposure to produce cross-lined effects and he was the first to achieve any commercial success with relief halftones. Shortly afterwards, Ives, this time in collaboration with Louis and Max Levy, improved the process further with the invention, the relief halftone process proved almost immediately to be a success. The use of blocks in popular journals became regular during the early 1890s. The development of printing methods for lithography appears to have followed a largely independent path. In the 1860s, A. Hoen & Co. focused on methods allowing artists to manipulate the tones of hand-worked printing stones, by the 1880s, Hoen was working on halftone methods that could be used in conjunction with either hand-worked or photolithographic stones. The most common method of creating screens—amplitude modulation—produces a regular grid of dots that vary in size, the other method of creating screens—frequency modulation—is used in a process also known as stochastic screening. Both modulation methods are named by analogy with the use of the terms in telecommunications, the resolution of a halftone screen is measured in lines per inch
3.
Ernst Haeckel
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The published artwork of Haeckel includes over 100 detailed, multi-colour illustrations of animals and sea creatures. As a philosopher, Ernst Haeckel wrote Die Welträtsel, the genesis for the term world riddle, Ernst Haeckel was born on 16 February 1834, in Potsdam. In 1852, Haeckel completed studies at the Domgymnasium, the high school of Merseburg. He then studied medicine in Berlin and Würzburg, particularly with Albert von Kölliker, Franz Leydig, Rudolf Virchow, together with Hermann Steudner he attended botany lectures in Würzburg. In 1857, Haeckel attained a doctorate in medicine, and afterwards he received a license to practice medicine, the occupation of physician appeared less worthwhile to Haeckel, after contact with suffering patients. Between 1859 and 1866, Haeckel worked on many phyla such radiolarians, poriferans, during a trip to the Mediterranean, Haeckel named nearly 150 new species of radiolarians. In 1867, he married Agnes Huschke and their son Walter was born in 1868, their daughters Elizabeth in 1871 and Emma in 1873. In 1869, he traveled as a researcher to Norway, in 1871 to Croatia, and in 1873 to Egypt, Turkey, Haeckel retired from teaching in 1909, and in 1910 he withdrew from the Evangelical church. Haeckels wife, Agnes, died in 1915, and Haeckel became substantially frailer, with a broken leg and he sold his Villa Medusa in Jena in 1918 to the Carl Zeiss foundation, and it presently contains a historic library. Haeckel died on 9 August 1919, Haeckels political beliefs were influenced by his affinity for the German Romantic movement coupled with his acceptance of a form of Lamarckism. Rather than being a strict Darwinian, Haeckel believed that the characteristics of an organism were acquired through interactions with the environment and he believed the social sciences to be instances of applied biology, and that phrase was picked up and used for Nazi propaganda. In 1905, Haeckel founded a group called the Monist League to promote his religious and this group lasted until 1933 and included such notable members as Wilhelm Ostwald, Georg von Arco, Helene Stöcker and Walter Arthur Berendsohn. Haeckel was the first person known to use the term First World War. Shortly after the start of the war Haeckel wrote, There is no doubt that the course, Haeckel was a zoologist, an accomplished artist and illustrator, and later a professor of comparative anatomy. For example, Haeckel described and named hypothetical ancestral microorganisms that have never been found and he was one of the first to consider psychology as a branch of physiology. He also proposed the kingdom Protista in 1866 and his chief interests lay in evolution and life development processes in general, including development of nonrandom form, which culminated in the beautifully illustrated Kunstformen der Natur. Haeckel did not support natural selection, rather believing in Lamarckism and it proposed a link between ontogeny and phylogeny, summed up by Haeckel in the phrase ontogeny recapitulates phylogeny. His concept of recapitulation has been refuted in the form he gave it, the strong recapitulation hypothesis views ontogeny as repeating forms of the ancestors, while weak recapitulation means that what is repeated is the ancestral embryonic development process
4.
Engraving
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Engraving is the practice of incising a design onto a hard, usually flat surface by cutting grooves into it. Wood engraving is a form of printing and is not covered in this article. Engraving was an important method of producing images on paper in artistic printmaking, in mapmaking. Other terms often used for printed engravings are copper engraving, copper-plate engraving or line engraving, hand engraving is a term sometimes used for engraving objects other than printing plates, to inscribe or decorate jewellery, firearms, trophies, knives and other fine metal goods. Traditional engravings in printmaking are also engraved, using just the same techniques to make the lines in the plate. Each graver is different and has its own use, engravers use a hardened steel tool called a burin, or graver, to cut the design into the surface, most traditionally a copper plate. Modern professional engravers can engrave with a resolution of up to 40 lines per mm in high grade work creating game scenes, dies used in mass production of molded parts are sometimes hand engraved to add special touches or certain information such as part numbers. In addition to engraving, there are engraving machines that require less human finesse and are not directly controlled by hand. They are usually used for lettering, using a pantographic system, there are versions for the insides of rings and also the outsides of larger pieces. Such machines are used for inscriptions on rings, lockets. Gravers come in a variety of shapes and sizes that yield different line types, the burin produces a unique and recognizable quality of line that is characterized by its steady, deliberate appearance and clean edges. The angle tint tool has a curved tip that is commonly used in printmaking. Florentine liners are flat-bottomed tools with multiple lines incised into them, ring gravers are made with particular shapes that are used by jewelry engravers in order to cut inscriptions inside rings. Flat gravers are used for work on letters, as well as wriggle cuts on most musical instrument engraving work, remove background. Knife gravers are for line engraving and very deep cuts, round gravers, and flat gravers with a radius, are commonly used on silver to create bright cuts, as well as other hard-to-cut metals such as nickel and steel. Square or V-point gravers are typically square or elongated diamond-shaped and used for cutting straight lines, V-point can be anywhere from 60 to 130 degrees, depending on purpose and effect. These gravers have very small cutting points, other tools such as mezzotint rockers, roulets and burnishers are used for texturing effects. Burnishing tools can also be used for stone setting techniques
5.
Sketch (drawing)
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A sketch is a rapidly executed freehand drawing that is not usually intended as a finished work. Sketches can be made in any drawing medium, the term is most often applied to graphic work executed in a dry medium such as silverpoint, graphite, pencil, charcoal or pastel. But it may apply to drawings executed in pen and ink, ballpoint pen, water colour. The latter two are referred to as water colour sketches and oil sketches. A sculptor might model three-dimensional sketches in clay, plasticine or wax, sketching is generally a prescribed part of the studies of art students. This generally includes making sketches from a model whose pose changes every few minutes. Underdrawing is drawing underneath the work, which may sometimes still be visible. Most visual artists use, to a greater or lesser degree, the term sketchbook refers to a book of blank paper on which an artist can, drawn sketches. The book might be purchased bound or might comprise loose leaves of sketches assembled or bound together, the ability to quickly record impressions through sketching has found varied purposes in todays culture. Courtroom sketches record scenes and individuals in law courts, Sketches drawn to help authorities find or identify wanted people are called composite sketches. Street artists in popular tourist areas sketch portraits within minutes, doodle Multi-Sketch Etch A Sketch, a toy Urban Sketchers This article incorporates text from a publication now in the public domain, Chisholm, Hugh, ed. article name needed. Media related to Sketches at Wikimedia Commons
6.
Watercolor
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Watercolor or watercolour, also aquarelle, a diminutive of the Latin for water, is a painting method in which the paints are made of pigments suspended in a water-based solution. Watercolor refers to both the medium and the resulting artwork, the traditional and most common support—material to which the paint is applied—for watercolor paintings is paper. Other supports include papyrus, bark papers, plastics, vellum, leather, fabric, wood, Watercolor paper is often made entirely or partially with cotton, which gives a good texture and minimizes distortion when wet. Watercolors are usually translucent, and appear luminous because the pigments are laid down in a form with few fillers obscuring the pigment colors. Watercolors can also be made opaque by adding Chinese white, in East Asia, watercolor painting with inks is referred to as brush painting or scroll painting. In Chinese, Korean and Japanese painting it has been the dominant medium, india, Ethiopia and other countries have long watercolor painting traditions as well. Fingerpainting with watercolor paints originated in mainland China, however, its continuous history as an art medium begins with the Renaissance. The German Northern Renaissance artist Albrecht Dürer, who painted several fine botanical, wildlife, an important school of watercolor painting in Germany was led by Hans Bol as part of the Dürer Renaissance. Despite this early start, watercolors were used by Baroque easel painters only for sketches, copies or cartoons. Notable early practitioners of watercolor painting were Van Dyck, Claude Lorrain, Giovanni Benedetto Castiglione, however, botanical illustration and wildlife illustration perhaps form the oldest and most important traditions in watercolor painting. Botanical illustrations became popular during the Renaissance, both as hand-tinted woodblock illustrations in books or broadsheets and as tinted ink drawings on vellum or paper. Wildlife illustration reached its peak in the 19th century with such as John James Audubon. Several factors contributed to the spread of watercolor painting during the 18th century, Watercolor artists were commonly brought with the geological or archaeological expeditions, funded by the Society of Dilettanti, to document discoveries in the Mediterranean, Asia, and the New World. This example popularized watercolors as a form of personal tourist journal, the confluence of these cultural, engineering, scientific, tourist, and amateur interests culminated in the celebration and promotion of watercolor as a distinctly English national art. William Blake published several books of hand-tinted engraved poetry, provided illustrations to Dantes Inferno, from the late 18th century through the 19th century, the market for printed books and domestic art contributed substantially to the growth of the medium. Satirical broadsides by Thomas Rowlandson, many published by Rudolph Ackermann, were extremely popular. Among the important and highly talented contemporaries of Turner and Girtin, were John Varley, John Sell Cotman, Anthony Copley Fielding, Samuel Palmer, William Havell, the Swiss painter Louis Ducros was also widely known for his large format, romantic paintings in watercolor. These societies provided annual exhibitions and buyer referrals for many artists, in particular, the graceful, lapidary, and atmospheric watercolors by Richard Parkes Bonington created an international fad for watercolor painting, especially in England and France in the 1820s
7.
Symmetry in biology
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Symmetry in biology is the balanced distribution of duplicate body parts or shapes within the body of an organism. In nature and biology, symmetry is always approximate, for example plant leaves, while considered symmetrical, symmetry creates a class of patterns in nature, where the near-repetition of the pattern element is by reflection or rotation. The body plans of most multicellular organisms exhibit some form of symmetry, whether radial, bilateral, a small minority, notably among the sponges, exhibit no symmetry. Radially symmetric organisms resemble a pie where several cutting planes produce roughly identical pieces, such an organism exhibits no left or right sides. They have a top and a surface only. Most radially symmetric animals are symmetrical about an axis extending from the center of the oral surface, radial symmetry is especially suitable for sessile animals such as the sea anemone, floating animals such as jellyfish, and slow moving organisms such as starfish. Animals in the phyla cnidaria and echinodermata are radially symmetric, although many sea anemones and some corals have bilateral symmetry defined by a single structure, many flowers are radially symmetric or actinomorphic. Roughly identical flower parts – petals, sepals, and stamens occur at intervals around the axis of the flower. Many viruses have radial symmetries, their coats being composed of a small number of protein molecules arranged in a regular pattern to form polyhedrons, spheres. Tetramerism is a variant of radial symmetry found in jellyfish, which have four canals in an otherwise radial body plan, pentamerism, another variant of radial symmetry, means the organism is in five parts around a central axis, 72° apart. Among animals, only the echinoderms such as sea stars, sea urchins, being bilaterian animals, however, they initially develop with mirror symmetry as larvae, then gain pentaradial symmetry later. Flowering plants show fivefold symmetry in many flowers and in various fruits and this is well seen in the arrangement of the five carpels in an apple cut transversely. Hexamerism is found in the corals and sea anemones which are divided into two based on their symmetry. The most common corals in the subclass Hexacorallia have a body plan, their polyps have sixfold internal symmetry. Octamerism is found in corals of the subclass Octocorallia and these have polyps with eight tentacles and octameric radial symmetry. The octopus, however, has symmetry, despite its eight arms. Spherical symmetry occurs in an if it is able to be cut into two identical halves through any cut that runs through the organisms center. Organisms which show approximate spherical symmetry include the green alga Volvox
8.
Evolution of biological complexity
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The evolution of biological complexity is one important outcome of the process of evolution. Some used to believe that evolution was progressive and had a direction that led towards so-called higher organisms, nonetheless, the Last Universal Common Ancestor is the most recent common ancestor of all current life on Earth. LUCA should not be assumed to be the first living organism on Earth, the LUCA is estimated to have lived some 3.5 to 3.8 billion years ago. The composition of the LUCA is not directly accessible as a fossil, by this means, a 2016 study identified a set of 355 genes inferred to have been present in the LUCA. Usually organisms that reproduce more quickly and plentifully than their competitors have an evolutionary advantage, consequently, organisms can evolve to become simpler and thus multiply faster and produce more offspring, as they require fewer resources to reproduce. A lineage can also dispense with complexity when a particular complex trait merely provides no advantage in a particular environment. Loss of this trait need not necessarily confer a selective advantage, for example, a parasitic organism may dispense with the synthetic pathway of a metabolite where it can readily scavenge that metabolite from its host. Mutations causing loss of a complex trait occur more often than mutations causing gain of a complex trait, with selection, evolution can also produce more complex organisms. This tremendous complexity allows the parasite to constantly change its surface and this trend may be reinforced by the fact that ecosystems themselves tend to become more complex over time, as species diversity increases, together with the linkages or dependencies between species. If evolution possessed an active trend toward complexity, then we would expect to see an increase over time in the most common value of complexity among organisms, indeed, some computer models have suggested that the generation of complex organisms is an inescapable feature of evolution. This is sometimes referred to as evolutionary self-organization, self-organization is the spontaneous internal organization of a system. This process is accompanied by an increase in complexity, resulting in an emergent property that is distinctly different from any of the constituent parts. However, the idea of increasing production of complexity in evolution can also be explained through a passive process, assuming unbiased random changes of complexity and the existence of a minimum complexity leads to an increase over time of the average complexity of the biosphere. As shown on the left, this involves an increase in variance, the trend towards higher complexity over time exists, but also involves increasingly smaller portions of biological life. Consequently, in view, microscopic life dominates Earth. In the 19th century, some such as Jean-Baptiste Lamarck. This belief may reflect then-current ideas of Hegel and of Herbert Spencer which envisaged the universe gradually evolving to a higher and this view regarded the evolution of parasites from independent organisms to a parasitic species as devolution or degeneration, and contrary to nature. Social theorists and propagandists have sometimes interpreted this approach metaphorically to decry certain categories of people as degenerate parasites, later scientists regard biological devolution as nonsense, rather, lineages will become simpler or more complicated according to whatever forms have a selective advantage
9.
Ostraciidae
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Ostraciidae is a family of squared, bony fish belonging to the order Tetraodontiformes, closely related to the pufferfishes and filefishes. Fish in the family are known variously as boxfishes, cofferfishes, cowfishes and trunkfishes and it contains about 23 extant species in 6 extant genera. Members of this occur in a variety of different colors. They swim in a rowing manner and their hexagonal plate-like scales are fused together into a solid, triangular or box-like carapace, from which the fins, tail, eyes and mouth protrude. Because of these heavy armoured scales, Ostraciidae are limited to slow movements, ostraciid boxfish of the genus Lactophrys also secrete poisons from their skin into the surrounding water, further protecting them from predation. Although the adults are in general quite square in shape, young Ostraciidae are more rounded, the young often exhibit brighter colors than the adults. The scrawled cowfish, Acanthostracion quadricornis, can grow up to 50 centimetres in length, the various members of this family are able to secrete cationic surfactants through their skin which can act as a chemical defense mechanism. Pahutoxin is a choline ester of 3-acetoxypalmitic acid that behaves similarly to steroidal saponins found in echinoderms. When this toxic mucus is released from the fish, it dissolves in the environment
