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Raking Light
Raking light, the illumination of objects from a light source at an oblique angle or almost parallel to the surface, provides information on the surface topography and relief of the artefact thus lit. It is widely used in the examination of works of art. Examination of paintings Using raking light, the effects of impasto and the surface texture of a painting are accentuated by the increased illumination of surfaces facing the light source and the exaggeration of shadows on surfaces facing away from the light source. In some instances raking light may help reveal pentimenti (changes in an artist's intention). In the case of wall paintings, raking light helps show preparatory techniques such as incisions in the plaster support. Conservation Conservators examine objects under raking light during visual inspection and for condition recording. In the examination of easel paintings, raking light may help document craquelure, paint cupping, uneven tension in a canvas, or warp in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Condition Recording
Condition or conditions may refer to: In philosophy and logic * Material conditional, a logical connective used to form "if...then..." statements * Necessary and sufficient condition, a statement which is true if and only if another given statement is true In science and technology In computer science * Exception handling#Condition systems, a generalization of exceptions in exception handling * Condition (SQL), a filtering mechanism in relational database queries * Condition variable, a synchronization primitive in concurrent programming In medicine * Medical condition, as a synonym for disease * Medical state or condition, a patient's clinical status in a hospital In numerical analysis * Condition number, a measure of a matrix in digital computation In arts and entertainment * ''Condition'' (film), a 2011 film * ''Conditions'' (album), 2009 debut album by Australian rock band The Temper Trap * ''Conditions'' (magazine), an annual lesbian feminist literary magazine * Con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Imaging
Imaging is the representation or reproduction of an object's form; especially a visual representation (i.e., the formation of an image). Imaging technology is the application of materials and methods to create, preserve, or duplicate images. Imaging science is a multidisciplinary field concerned with the generation, collection, duplication, analysis, modification, and visualization of images,Joseph P. Hornak, ''Encyclopedia of Imaging Science and Technology'' (John Wiley & Sons, 2002) including imaging things that the human eye cannot detect. As an evolving field it includes research and researchers from physics, mathematics, electrical engineering, computer vision, computer science, and perceptual psychology. ''Imager'' are imaging sensors. Imaging chain The foundation of imaging science as a discipline is the "imaging chain" – a conceptual model describing all of the factors which must be considered when developing a system for creating visual renderings (images). In g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Delamination
Delamination is a mode of failure where a material fractures into layers. A variety of materials including laminate composites and concrete can fail by delamination. Processing can create layers in materials such as steel formed by rolling and plastics and metals from 3D printing which can fail from layer separation. Also, surface coatings such as paints and films can delaminate from the coated substrate. In laminated composites, the adhesion between layers often fails first causing the layers to separate. For example, in fiber-reinforced plastics, sheets of high strength reinforcement (e.g., carbon fiber, fiberglass) are bound together by a much weaker polymer matrix (e.g., epoxy). In particular, loads applied perpendicular to the high strength layers, and shear loads can cause the polymer matrix to fracture or the fiber reinforcement to debond from the polymer. Delamination also occurs in reinforced concrete when metal reinforcements near the surface corrode. The oxid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salt (chemistry)
In chemistry, a salt is a chemical compound consisting of an ionic assembly of positively charged cations and negatively charged anions, which results in a compound with no net electric charge. A common example is table salt, with positively charged sodium ions and negatively charged chloride ions. The component ions in a salt compound can be either inorganic, such as chloride (Cl−), or organic, such as acetate (). Each ion can be either monatomic, such as fluoride (F−), or polyatomic, such as sulfate (). Types of salt Salts can be classified in a variety of ways. Salts that produce hydroxide ions when dissolved in water are called '' alkali salts'' and salts that produce hydrogen ions when dissolved in water are called '' acid salts''. ''Neutral salts'' are those salts that are neither acidic nor basic. Zwitterions contain an anionic and a cationic centre in the same molecule, but are not considered salts. Examples of zwitterions are amino acids, many metabol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Efflorescence
In chemistry, efflorescence (which means "to flower out" in French) is the migration of a salt to the surface of a porous material, where it forms a coating. The essential process involves the dissolving of an internally held salt in water, or occasionally in another solvent. The water, with the salt now held in solution, migrates to the surface, then evaporates, leaving a coating of the salt. In what has been described as "primary efflorescence", the water is the invader and the salt was already present internally, and a reverse process, where the salt is originally present externally and is then carried inside in solution, is referred to as "secondary efflorescence". Efflorescences can occur in natural and built environments. On porous construction materials it may present a cosmetic outer problem only (primary efflorescence causing staining), but can sometimes indicate internal structural weakness (migration/degradation of component materials). Efflorescence may clog the p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Murals
A mural is any piece of graphic artwork that is painted or applied directly to a wall, ceiling or other permanent substrate. Mural techniques include fresco, mosaic, graffiti and marouflage. Word mural in art The word ''mural'' is a Spanish adjective that is used to refer to what is attached to a wall. The term ''mural'' later became a noun. In art, the word mural began to be used at the beginning of the 20th century. In 1906, Dr. Atl issued a manifesto calling for the development of a monumental public art movement in Mexico; he named it in Spanish ''pintura mural'' (English: ''wall painting''). In ancient Roman times, a mural crown was given to the fighter who was first to scale the wall of a besieged town. "Mural" comes from the Latin ''muralis'', meaning "wall painting". History Antique art Murals of sorts date to Upper Paleolithic times such as the cave paintings in the Lubang Jeriji Saléh cave in Borneo (40,000-52,000 BP), Chauvet Cave in Ardèche departmen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hamilton Kerr Institute
The Hamilton Kerr Institute is a branch of the Fitzwilliam Museum in Cambridgeshire, England, dedicated to the study and conservation of easel paintings. It is also part of the University of Cambridge. Facilities and logistics The institute was founded in 1976 through grants from the Baring Foundation, the Esmée Fairbairn Trust, the Gulbenkian Foundation, the Isaac Wolfson Foundation, the Monument Trust, and the Pilgrim Trust, and continues to finance itself through income from its work and its endowment fund. It is housed in a riverside property, donated by Hamilton Kerr, seven miles south of Cambridge in the village of Whittlesford. The premises consist of a mid-eighteenth century house and converted mill buildings, containing offices and a scientific laboratory, restoration studios, studios for panel treatment and the relining of canvases, and studios for photography. In 1980, the institute opened a studio in London. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Panel Painting
A panel painting is a painting made on a flat panel of wood, either a single piece or a number of pieces joined together. Until canvas became the more popular support medium in the 16th century, panel painting was the normal method, when not painting directly onto a wall (fresco) or on vellum (used for miniatures in illuminated manuscripts). Wood panels were also used for mounting vellum paintings. History Panel painting is very old; it was a very prestigious medium in Greece and Rome, but only very few examples of ancient panel paintings have survived. A series of 6th century BC painted tablets from Pitsa (Greece) represent the oldest surviving Greek panel paintings. Most classical Greek paintings that were famous in their day seem to have been of a size comparable to smaller modern works – perhaps up to a half-length portrait size. However, for a generation in the second quarter of the fifth-century BC there was a movement, called the "new painting" and led by Polygnotus, f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wood Warping
Wood warping is a deviation from flatness in timber as a result of stresses and uneven shrinkage. Warping can also occur in wood considered "dry" (wood can take up and release moisture indefinitely), when it takes up moisture unevenly, or – especially – is allowed to return to its "dry" equilibrium state unevenly, too slowly, or too quickly. Many factors can contribute to wood warp: wood species, grain orientation, air flow, sunlight, uneven finishing, temperature – even cutting season and the moon's gravitational pull are taken into account in some traditions (e.g., violin making). The types of wood warping include: * bow: a warp along the length of the face of the wood * crook: a warp along the length of the edge of the wood * kink: a localized crook, often due to a knot * cup: a warp across the width of the face, in which the edges are higher or lower than the center of the wood * twist or wind: a distortion in which the two ends do not lie on the same plane. Winding s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canvas
Canvas is an extremely durable plain-woven fabric used for making sails, tents, marquees, backpacks, shelters, as a support for oil painting and for other items for which sturdiness is required, as well as in such fashion objects as handbags, electronic device cases, and shoes. It is popularly used by artists as a painting surface, typically stretched across a wooden frame. Modern canvas is usually made of cotton or linen, or sometimes polyvinyl chloride (PVC), although historically it was made from hemp. It differs from other heavy cotton fabrics, such as denim, in being plain weave rather than twill weave. Canvas comes in two basic types: plain and duck. The threads in duck canvas are more tightly woven. The term ''duck'' comes from the Dutch word for cloth, ''doek''. In the United States, canvas is classified in two ways: by weight (ounces per square yard) and by a graded number system. The numbers run in reverse of the weight so a number 10 canvas is lighter than ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tension (physics)
In physics, tension is described as the pulling force transmitted axially by the means of a string, a rope, chain, or similar object, or by each end of a rod, truss member, or similar three-dimensional object; tension might also be described as the action-reaction pair of forces acting at each end of said elements. Tension could be the opposite of compression. At the atomic level, when atoms or molecules are pulled apart from each other and gain potential energy with a restoring force still existing, the restoring force might create what is also called tension. Each end of a string or rod under such tension could pull on the object it is attached to, in order to restore the string/rod to its relaxed length. Tension (as a transmitted force, as an action-reaction pair of forces, or as a restoring force) is measured in newtons in the International System of Units (or pounds-force in Imperial units). The ends of a string or other object transmitting tension will exert forces on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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