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40-482: About 200 celadon sites are distributed in the area where the Goryeo Celadon Museum is located. It can be said to be the birthplace and treasure trove of Goryeo celadon. The museum's collection has about 30,000 pieces of Goryeo celadons and actively holds exhibitions for informing the people about Korean Celadons and its props. Some of kilns were reconstructed to reenact the way people of Goryeo made

80-449: A coloured stain, in different colours. There are multiple layers of glaze, and the wider crackle develops first, with the finer one developing inside those sections. The crackle may take some time to appear after firing and is probably mainly caused by rapid cooling and perhaps low silica in the glaze. The modern decor industry has used the technique of craquelure to create various objects and materials such as glass, ceramics, iron. This

120-404: A critical strain, ϵ m {\displaystyle \epsilon _{m}} , is opposed by an unfavorable increase in surface energy as the crack elongates and promoted by a release in the elastic energy of the material near the crack. The condition for the propagation of a drying crack can be evaluated precisely using fracture mechanics . Crack width is heavily dependent on

160-628: A definite composition starting from the 11th century to the 15th century. It contained a lot of calcium in composition, with 0.5% of manganese oxide , which was more concentrated than glaze used in Chinese celadon. Also in the case of Chinese ceramics, there is enough time for nucleation-crystal growth, so it takes jade color. But the kilns in Goryeo were smaller than that in China, so the firing and cooling process took place quickly. Therefore, minerals in

200-473: A native style by the 12th century. One of these native styles is characterized by the sanggam technique, a way of inlaying that was unique to Goryeo celadon. The color of the celadon, called bisaek for 'green', was also highly admired. The industry arose and declined as the Goryeo dynasty developed. Many wares were produced at the Gangjin Kiln Sites in southwestern Korea. An artist of

240-412: A result of drying, shock, aging, intentional patterning, or a combination of all four. The term is most often used to refer to tempera or oil paintings , but it can also develop in old ivory carvings or painted miniatures on an ivory backing. Recently, analysis of craquelure has been proposed as a way to authenticate art. In ceramics, craquelure in ceramic glazes , where it is often a desired effect,

280-410: A way to use formaldehyde and a special baking process. Craquelure is almost impossible to accurately reproduce artificially in a particular pattern, although there are some methods such as baking or finishing of a painting by which this is attempted. These methods, however, generally achieve cracks that are uniform in appearance, while genuine craquelure has cracks with irregular patterns. Craquelure

320-499: Is brittle at relative humidities (RH) below 75%; as RH increases, gesso becomes less stiff and transitions to a ductile state. Variations in RH cause highly non-uniform tensile strains across the gesso surface, and when the material contracts upon drying, it fractures. Craquelure formed during gesso drying are particularly noticeable. Similarly, wood supports respond significantly to changes in RH. Wood grains tend to swell perpendicular to

360-452: Is called "crackle"; it is a characteristic of Chinese Ge ware in particular. This is usually differentiated from crazing , which is a glaze defect in firing, or the result of aging or damage. Painting systems are composed of complex layers with unique mechanical properties that depend on the type of drying oil or paint medium used and the presence of paint additives, such as organic solvents , surfactants , and plasticizers . Understanding

400-438: Is considered as a zenith of Goryeo celadon, especially in its special color and harmony. The pure celadon made in this age had thin glaze coating that exquisitely reflected the jade color, called bisaek . They also had a great level of structural balance and elegance. There are records describing celadon of this age as world best. Jinsa "underglaze red", a technique using copper oxide pigment to create copper-red designs,

440-431: Is engraved on the vessel's body with a knife and the carved-away areas are filled with purple or white clay. When the clay dries the excess is removed, leaving it only in the carved areas, leaving a white or purple pattern. The entire vessel is coated in a colorless glaze. Once it is fired, the white clay still appears white but the purple turns black, and the pattern is visible through the glaze. Glaze of Goryeo celadon had

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480-429: Is frequently induced by using zinc white paints as the underlayer in pentimento techniques. Zinc whites with small zinc oxide particles (~250 nm) are more successful at inducing craquelure than larger particles because it does not adhere to the sublayer. Additionally, zinc white paints using linoleic acid-based binders are more successful at producing craquelure than paints with other binders. Craquelure affecting

520-472: Is seen throughout the porcelain produced in this time. Though the celadon industry remained, overall density of expressions and smoothness decreased and the color and harmony are also diminished. This decrease in its beauty continues as the Goryeo dynasty recedes. In the late 14th Century, the Kilns of Gangjin and Buanyo were attacked by Japanese pirates and closed. Inland kilns replace them, putting an end to

560-485: Is the elastic modulus of the pictorial layer, Γ {\displaystyle \Gamma } the surface energy of this layer, Z a dimensionless constant that depends on the cracking pattern, and σ {\displaystyle \sigma } the stress experienced during drying. Films thicker than this critical value display networks of cracks. The degree of connectivity between nucleation sites increases with film thickness, so that thicknesses near

600-563: Is the elastic modulus of the sublayer. The denominator in this approximation indicates that crack spacing is dependent on the mismatch in the elastic moduli of the two layers; therefore, regions with stiffer paints tend to have cracks that are more spread out. Changes in the relative humidity during the drying process affect both the ground layer and support of a painting, promoting crack propagation. Paintings involving hygroscopic materials like wood supports or gesso ground layers are especially susceptible to variations in relative humidity. Gesso

640-467: Is the stiffness of the pictorial layer. The crack spacing for an infinitely stiff support is approximated by: d ≈ 4 h Γ E p a ϵ m 2 {\displaystyle d\approx {\frac {4h\Gamma }{E_{p}a\epsilon _{m}^{2}}}} where h {\displaystyle h} is the thickness of the pictorial layer, Γ {\displaystyle \Gamma }

680-523: The Song and Yuan dynasties with deliberate crackle glazes are Guan ware and Ge ware ; in Ru ware , the milder crackle may be accidental, though the majority of pieces have it. Ge ware can have a type of double crackle, known as "gold thread and iron wire", where there are two patterns, one with wide and large crackle and the other with a finer network. Each set of cracks has had the effect heightened by applying

720-423: The ability of the top paint layer to adhere to the sublayer. If poor adhesion between these layers occurs, the pictorial layer can slide over the sublayer and create dramatic, wide cracks in response to uneven tensile strains during solvent evaporation. Unlike aging cracks, the width of drying cracks is highly varying as a result. Poor adhesion can occur if the painter mixes too much oil or other fatty substance into

760-475: The age of celadon. Though new characteristic shapes and designs appear, they are utilitarian instead of being elegant and restrained, as Goryeo celadon in its zenith did. One of these new types of porcelain is called buncheong . A revival of Goryeo celadon pottery began in the early 20th century. Playing a leading role in its revival in South Korea was Yu Geun-Hyeong , a Living National Treasure whose work

800-558: The celadons. This article related to a museum in South Korea is a stub . You can help Misplaced Pages by expanding it . Goryeo celadon Goryeo ware ( Korean : 고려도자기 , romanized :  Goryeo dojagi , also known as Goryeo cheong-ja ) refers to all types of Korean pottery and porcelain produced during the Goryeo dynasty, from 918 to 1392, but most often refers to celadon (greenware). Celadon techniques were first introduced from China; Goryeo potters established

840-520: The critical value are characterized by isolated star-shaped crack junctions and thick films show more complete networks. The spacing of cracks during drying depends strongly on the stiffness of the support, or sublayer. An infinitely stiff sublayer does not contribute to the strain in the pictorial layer, so that ϵ p = ϵ m {\displaystyle \epsilon _{p}=\epsilon _{m}} , where ϵ p {\displaystyle \epsilon _{p}}

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880-476: The decrease of Chinese influence, Goryeo celadon acquires a more native shape, in unique patterns and decorative shapes. Thin, transparent glaze used to show the inlaid designs led to development of a crackling cooling pattern, called bingyeol ( craquelure ). After the Mongolian invasion in 1220, social and economic confusion had caused the general quality of Goryeo celadon to decline. Influence of Yuan dynasty

920-523: The development of tea culture and Buddhism , wares based on traditional and southern China ( Song dynasty ) porcelain began production in Goryeo . Most of the pottery made in this era are the kinds that are called haemurigup celadon and green celadon (low-grade) As the celadon techniques of the Song dynasty reached its pinnacle, much effort was made inside Goryeo to reproduce the turquoise coloring of these Chinese porcelain. A lot of kilns were made throughout

960-641: The glaze in ceramics may develop with age but has also been used as a deliberate decorative effect, which has a long history in Korean and Chinese pottery in particular. These deliberate glazing effects are usually known as "crackle", with crackle[d] glaze or "crackle porcelain" being common terms. It is typically distinguished from crazing , which is accidental craquelure arising as a glaze defect , although in some cases, experts have difficulty in deciding whether milder effects are deliberate or not. Some may also only have developed with age. Leading Chinese wares of

1000-430: The glaze such as anorthite or wollastonite did not have sufficient time for nucleation-crystal growth. This results in the color of celadon being closer to the gray side. In Goryeo celadon, quartz , black particles, bubbles, cracks can also be observed. Craquelure Craquelure ( French : craquelure ; Italian : crettatura ) is a fine pattern of dense cracking formed on the surface of materials. It can be

1040-402: The grain axis when they are exposed to moisture. As a wet ground layer is applied to the surface of a wood support, the wood in contact with the layer swells while the back of the panel remains unchanged. This can contribute to cupping, in which the panel of wood starts to bow transverse to the wood grain. The increased strains on the convex side of the cupped wood panel causes further fracture in

1080-586: The ground layer as it dries. Compared to their drying counterparts, aging cracks are sharper, deeper, and are developed over the lifetime of the painting. This type of craquelure is much more difficult to predict and model because it depends on the specific environmental changes and chemical aging reactions the paint is subjected to. Critical processes that contribute to aging craquelure include direct impacts, gradients in temperature and relative humidity, support deformation, restoration processes like canvas reinforcement and stretching, and oxidation reactions that make

1120-584: The kingdom, leading to a variety of celadon being made. High grade celadon were made in order of the capital, and low grade celadon were made by the requests of temples, offices and local families of provinces. Though Chinese influences were still existent, Goryeo styled shapes and decorations emerged in some porcelains. These are characterized by the utilization of light curves and a serene, elegant feel. Decoration techniques such as relief carving, intaglio carving, iron oxide glaze, openwork became in use. The sanggam inlaying also started at this age. The 12th century

1160-533: The mechanism of craquelure formation in paint and the resulting crack morphology provides information about the methods and materials used by the artists. There are seven key features used to describe craquelure morphology: These seven criteria have been used to identify "styles" of craquelure, which relate crack patterns to various historic schools of art. This links the crack patterns with specific time periods, locations, and painting styles. Paintings do not have flat surfaces but rather an uneven texture because of

1200-399: The pictorial layer tends to shrink as volatile solvents evaporate. Non-uniform shrinkage across the painting surface is caused by differential adhesion to the sublayer by different paint species and leads to large tensile stresses in the top paint layer. Crack formation during drying depends strongly on adhesion to the sublayer, paint film thickness, composition, and the mechanical properties of

1240-562: The post-war era who specialised in Goryeo ware was Living National Treasure Yu Geun-Hyeong . His work was documented in the short film Koryo Celadon in 1979. Many celadon pieces from Goryeo are listed as National Treasures of South Korea . Pottery and celadon had been introduced into the Korean peninsula in the Three Kingdom age . Demand for higher quality porcelain increased as the Goryeo Dynasty emerged. Along with

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1280-559: The ratio of the strains between the two layers is approximately the same as the ratio of their elastic moduli, the crack spacing for a support with finite stiffness can be approximated as: d ≈ 4 h Γ E p a ϵ p 2 ( 1 + E p / E s ) 2 {\displaystyle d\approx {\frac {4h\Gamma }{E_{p}a\epsilon _{p}^{2}(1+E_{p}/E_{s})^{2}}}} where E s {\displaystyle E_{s}}

1320-637: The sublayer material. Below a critical film thickness, h c {\displaystyle h_{c}} , the pictorial layer will remain crack-free. Cracks are not able to propagate in thin films because the decrease in elastic energy as the crack elongates is not enough to negate the concurrent increase in surface energy. The critical film thickness is approximated by: h c = E p Γ Z σ 2 {\displaystyle h_{c}={\frac {E_{p}\Gamma }{Z\sigma ^{2}}}} where E p {\displaystyle E_{p}}

1360-449: The sublayer. Craquelure formed during the drying process appears within days of painting and is characterized by shallow cracks that are localized to the topmost layers of paint. This localization results from capillary forces, which constrain drying stresses to the free surface of the painting. Drying cracks are usually isotropic due to the fine dispersion of pigment particles within the evaporating volatile solvents. Crack propagation at

1400-429: The surface chalky or more brittle. In general, the pictorial layer becomes more brittle as it ages, which makes it unable to accommodate the stresses induced by environmental factors. Induced craquelure can be created by a variety of techniques, and in paintings is often used by forgers of Old Master paintings, which would normally show some. Art forger Eric Hebborn developed a technique and Tony Tetro discovered

1440-604: The surface energy of the pictorial layer, E p {\displaystyle E_{p}} the elastic modulus of the pictorial layer, and a {\displaystyle a} the depth of the crack. For a less stiff sublayer, an additional strain in the sublayer, ϵ s {\displaystyle \epsilon _{s}} , lessens the strain in the pictorial layer such that ϵ m − ϵ s = ϵ p {\displaystyle \epsilon _{m}-\epsilon _{s}=\epsilon _{p}} . If

1480-407: The wood, animal glue, ground or gesso , paint, binder used, etc. Since the elements used to create paintings vary by region, surface textures can also vary according to where they were produced. Italian painters usually used a thin ground surface, which led to their work developing skinny, thin cracks, while French painters have swirling cracks because of a much thicker ground surface. During drying,

1520-570: Was developed in Korea during the 12th century, and later inspired the "underglaze red" ceramics of the Yuan dynasty . Maturation of the aristocrat society due to events such as the coup of military officers leads to an increasing favor for extravagantly decorated porcelain. Inlaying techniques reach its height and opens a second zenith of Goryeo celadon. Other types of porcelain develop as whitening, iron oxide glaze, copper oxide glaze came in use. With

1560-403: Was documented in the 1979 short film, Koryo Celadon . North Korean potter U chi-son separately recreated Goryeo celadon pottery. For the inlay technique, several patterns are engraved on the surface of metal, clay, wood, etc. This traditional decoration technique started to be applied in porcelain in the Goryeo dynasty. Purple (black) and white clay were used to show the patterns. A pattern

1600-529: Was made possible by the use of marketing kits that react with the colors used in decorative acrylic colors. The extent of craquelure produced varies according to the percentage of reagent and time of use. To highlight the cracks, glitter powder—usually available in copper, bronze and gold—is used. Mixing different brands of ready-made products to mimic craquelure results in various sizes and patterns of cracks. Software programs are available for creating craquelure in digital photos. Methods that utilize craquelure as

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