Porcelain /ˈpɔːrsəlᵻn, ˈpɔːrslᵻn/ is a ceramic material made by heating materials, generally including kaolin, in a kiln to temperatures between 1,200 and 1,400 °C. Porcelain was first developed in China around 2,000 years ago, spread to other East Asian countries, and finally Europe. It combines well with both glazes and paint, and can be modelled very well, allowing a range of decorative treatments in tablewares, vessels. It has uses in technology and industry. The European name, porcelain in English, come from the old Italian porcellana because of its resemblance to the translucent surface of the shell, Porcelain is referred to as china or fine china in some English-speaking countries, as it was first seen in imports from China. Porcelain has been described as being completely vitrified, impermeable, white or artificially coloured, however, the term porcelain lacks a universal definition and has been applied in a very unsystematic fashion to substances of diverse kinds which have only certain surface-qualities in common.
Terms such as porcellaneous or near-porcelain may be used in such cases, a high proportion of modern porcelain is made of the variant bone china. Kaolin is the material from which porcelain is made, even though clay minerals might account for only a small proportion of the whole. The word paste is an old term for both the unfired and fired material, a more common terminology these days for the unfired material is body, for example, when buying materials a potter might order an amount of porcelain body from a vendor. The composition of porcelain is highly variable, but the mineral kaolinite is often a raw material. Other raw materials can include feldspar, ball clay, bone ash, quartz, the clays used are often described as being long or short, depending on their plasticity. Long clays are cohesive and have high plasticity, short clays are cohesive and have lower plasticity. Clays used for porcelain are generally of lower plasticity and are shorter than many other pottery clays and they wet very quickly, meaning that small changes in the content of water can produce large changes in workability.
Thus, the range of content within which these clays can be worked is very narrow. The following section provides information on the methods used to form, finish, glaze. Many types of glaze, such as the iron-containing glaze used on the wares of Longquan, were designed specifically for their striking effects on porcelain. Porcelain wares may be decorated under the glaze using pigments that include cobalt and copper or over the glaze using coloured enamels. Like many earlier wares, modern porcelains are often biscuit-fired at around 1,000 °C, coated with glaze, another early method is once-fired where the glaze is applied to the unfired body and the two fired together in a single operation
Iran, known as Persia, officially the Islamic Republic of Iran, is a sovereign state in Western Asia. Comprising a land area of 1,648,195 km2, it is the second-largest country in the Middle East, with 82.8 million inhabitants, Iran is the worlds 17th-most-populous country. It is the country with both a Caspian Sea and an Indian Ocean coastline. The countrys central location in Eurasia and Western Asia, and its proximity to the Strait of Hormuz, Tehran is the countrys capital and largest city, as well as its leading economic and cultural center. Iran is the site of to one of the worlds oldest civilizations, the area was first unified by the Iranian Medes in 625 BC, who became the dominant cultural and political power in the region. The empire collapsed in 330 BC following the conquests of Alexander the Great, under the Sassanid Dynasty, Iran again became one of the leading powers in the world for the next four centuries. Beginning in 633 AD, Arabs conquered Iran and largely displaced the indigenous faiths of Manichaeism and Zoroastrianism by Islam, Iran became a major contributor to the Islamic Golden Age that followed, producing many influential scientists, scholars and thinkers.
During the 18th century, Iran reached its greatest territorial extent since the Sassanid Empire, through the late 18th and 19th centuries, a series of conflicts with Russia led to significant territorial losses and the erosion of sovereignty. Popular unrest culminated in the Persian Constitutional Revolution of 1906, which established a monarchy and the countrys first legislative body. Following a coup instigated by the U. K. Growing dissent against foreign influence and political repression led to the 1979 Revolution, Irans rich cultural legacy is reflected in part by its 21 UNESCO World Heritage Sites, the third-largest number in Asia and 11th-largest in the world. Iran is a member of the UN, ECO, NAM, OIC. Its political system is based on the 1979 Constitution which combines elements of a democracy with a theocracy governed by Islamic jurists under the concept of a Supreme Leadership. A multicultural country comprising numerous ethnic and linguistic groups, most inhabitants are Shia Muslims, the largest ethnic groups in Iran are the Persians, Azeris and Lurs.
Historically, Iran has been referred to as Persia by the West, due mainly to the writings of Greek historians who called Iran Persis, meaning land of the Persians. As the most extensive interactions the Ancient Greeks had with any outsider was with the Persians, Persis was originally referred to a region settled by Persians in the west shore of Lake Urmia, in the 9th century BC. The settlement was shifted to the end of the Zagros Mountains. In 1935, Reza Shah requested the international community to refer to the country by its native name, opposition to the name change led to the reversal of the decision, and Professor Ehsan Yarshater, editor of Encyclopædia Iranica, propagated a move to use Persia and Iran interchangeably
Feldspars are a group of rock-forming tectosilicate minerals that make up about 40% of the Earths continental crust. Feldspars crystallize from magma as veins in both intrusive and extrusive rocks and are present in many types of metamorphic rock. Rock formed almost entirely of plagioclase feldspar is known as anorthosite. Feldspars are found in types of sedimentary rocks. The name feldspar derives from the German Feldspat, a compound of the words Feld and Spat, the change from Spat to -spar was influenced by the English word spar, a synonym for mineral. Feldspathic refers to materials that contain feldspar, the alternate spelling, has largely fallen out of use. This group of minerals consists of tectosilicates, solid solutions between albite and anorthite are called plagioclase, or more properly plagioclase feldspar. Only limited solid solution occurs between K-feldspar and anorthite, and in the two solid solutions, immiscibility occurs at temperatures common in the crust of the earth. Albite is considered both a plagioclase and alkali feldspar, the alkali feldspars are as follows, orthoclase —KAlSi3O8 sanidine —AlSi3O8 microcline —KAlSi3O8 anorthoclase —AlSi3O8 Sanidine is stable at the highest temperatures, and microcline at the lowest.
Perthite is a texture in alkali feldspar, due to exsolution of contrasting alkali feldspar compositions during cooling of an intermediate composition. The perthitic textures in the alkali feldspars of many granites can be seen with the naked eye, microperthitic textures in crystals are visible using a light microscope, whereas cryptoperthitic textures can be seen only with an electron microscope. Barium feldspars are considered alkali feldspars, barium feldspars form as the result of the substitution of barium for potassium in the mineral structure. The barium feldspars are monoclinic and include the following, celsian—BaAl2Si2O8 hyalophane—4O8 The plagioclase feldspars are triclinic, the immiscibility gaps in the plagioclase solid solutions are complex compared to the gap in the alkali feldspars. The play of colours visible in some feldspar of labradorite composition is due to very fine-grained exsolution lamellae, chemical weathering of feldspars results in the formation of clay minerals.
About 20 million tonnes of feldspar were produced in 2010, mostly by three countries, Italy and China, Feldspar is a common raw material used in glassmaking, and to some extent as a filler and extender in paint and rubber. In glassmaking, alumina from feldspar improves product hardness, durability, in ceramics, the alkalis in feldspar act as a flux, lowering the melting temperature of a mixture. Fluxes melt at a stage in the firing process, forming a glassy matrix that bonds the other components of the system together. In the US, about 66% of feldspar is consumed in glassmaking, including glass containers and other uses, such as fillers, accounted for the remainder
East Asia is the eastern subregion of the Asian continent, which can be defined in either geographical or ethno-cultural terms. Geographically and geopolitically, it includes China, Mongolia and Japan, it covers about 12,000,000 km2, or about 28% of the Asian continent, the East Asian people comprise more than 1.5 billion people. About 38% of the population of Asia and 22%, or over one fifth, the overall population density of the region is 133 inhabitants per square kilometre, about three times the world average of 45/km2. Historically, societies in East Asia have been part of the Chinese cultural sphere, major religions include Buddhism, Confucianism or Neo-Confucianism, Chinese folk religion in China and Taiwan, Shinto in Japan, Korean shamanism in Korea. Shamanism is prevalent among Mongolians and other populations of northern East Asia. The Chinese calendar is the root from which many other East Asian calendars are derived, Chinese Dynasties dominated the region in matters of culture and exploration as well as militarily for a very long time.
There are records of tributes sent overseas from the kingdoms of Korea. There were considerable levels of cultural and religious exchange between the Chinese and other regional Dynasties and Kingdoms, as connections began to strengthen with the Western world, Chinas power began to diminish. Around the same time, Japan solidified itself as a nation state, throughout World War II, Taiwan, much of eastern China, Hong Kong, and Vietnam all fell under Japanese control. Culturally, Japan, Korea and Vietnam are commonly seen as being encompassed by cultural East Asia, there are mixed debates around the world whether these countries or regions should be considered in East Asia or not. Vietnam Siberia in Russia Sovereignty issues exist over some territories in the South China Sea, however, in this context, the term Far East is often more appropriate which covers ASEAN countries and the countries in East Asia. However, being a Eurocentric term, Far East describes the geographical position in relation to Europe rather than its location within Asia.
Alternatively, the term Asia Pacific Region is often used in describing East Asia and this usage, which is seen in economic and diplomatic discussions, is at odds with the historical meanings of both East Asia and Northeast Asia. The Council on Foreign Relations defines Northeast Asia as Japan and Korea, the military and economic superpower of China became the largest economy in the world in 2014, surpassing the United States of America. Currently in East Asia, trading systems are open, and zero or low duties on imports of consumer and capital goods etc. have considerably helped stimulate cost-efficiency. Free and flexible labor and other markets are important factors making for high levels of business-economic performance. East Asian populations have demonstrated highly positive work ethics, there are relatively large and fast-growing markets for consumer goods and services of all kinds. The culture of East Asia has been influenced by the civilisation of China, East Asia, as well as Vietnam, share a Confucian ethical philosophy, Buddhism and legal structures, and historically a common writing system
In pottery, a potters wheel is a machine used in the shaping of round ceramic ware. The wheel may be used during the process of trimming the excess body from dried ware, use of the potters wheel became widespread throughout the Old World but was unknown in the Pre-Columbian New World, where pottery was handmade by methods that included coiling and beating. A potters wheel may occasionally be referred to as a potters lathe, that term is better used for another kind of machine that is used for a different shaping process, similar to that used for shaping of metal and wooden articles. The jigger tool shapes one face, the mould the other, the term is specific to the shaping of flat ware, such as plates, whilst a similar technique, refers to the production of hollow ware, such as cups. Much early ceramic ware was hand-built using a coiling technique in which clay was rolled into long threads that were pinched. In the coiling method of construction, all the required to form the main part of a piece is supplied indirectly by the hands of the potter.
Early ceramics built by coiling were often placed on mats or large leaves to allow them to be worked more conveniently, the evidence of this lies in mat or leaf impressions left in the clay of the base of the pot. This arrangement allowed the potter to rotate the vessel during construction, the earliest forms of the potters wheel were probably developed as an extension to this procedure. Tournettes, in use around 4500 BC in the Near East, were turned slowly by hand or by foot while coiling a pot, only a small range of vessels were fashioned on the tournette, suggesting that it was used by a limited number of potters. The introduction of the wheel increased the efficiency of hand-powered pottery production. In the mid to late 3rd millennium BC the fast wheel was developed and it utilised energy stored in the rotating mass of the heavy stone wheel itself to speed the process. This wheel was wound up and charged with energy by kicking, or pushing it around with a stick, providing a centrifugal force.
The fast wheel enabled a new process of pottery-making to develop, called throwing, in which a lump of clay was placed centrally on the wheel, potters could now produce many more pots per hour, a first step towards industrialization. Many modern scholars suggest that the first potters wheel was first developed in Mesopotamia, southeastern Europe and China have been claimed as possible places of origin. Furthermore, the wheel was in use by potters starting around 3500 BC in major cities of the Indus Valley civilization in South Asia, namely Harappa. Others consider Egypt as being the place of origin of the potters wheel and it was here that the turntable shaft was lengthened about 3000 BC and a flywheel added. The flywheel was kicked and was moved by pulling the edge with the hand while forming the clay with the right. This led to the motion for the potters wheel which is almost universal
Faience or faïence is the conventional name in English for fine tin-glazed pottery on a delicate pale buff earthenware body. It is originally associated by French speakers with wares exported from Faenza in northern Italy. The invention of a white pottery glaze suitable for painted decoration, the invention seems to have been made in Iran or the Middle East before the ninth century. A kiln capable of producing temperatures exceeding 1,000 °C was required to achieve this result, the result of millennia of refined pottery-making traditions. The term is now used for a variety of pottery from several parts of the world, including many types of European painted wares. Technically, lead-glazed earthenware, such as the French sixteenth-century Saint-Porchaire ware, does not properly qualify as faience, semi-vitreous stoneware may be glazed like faience. However, this material is not pottery at all, containing no clay, the Metropolitan Museum of Art displays a faience hippopotamus from Meir, dated to Dynasty 12, ca.
Examples of ancient faience are found in Minoan Crete, which was influenced by Egyptian culture. Faience material, for instance, has recovered from the Knossos archaeological site. The Moors brought the technique of tin-glazed earthenware to Al-Andalus, where the art of lustreware with metallic glazes was perfected, from Málaga in Andalusia and Valencia these Hispano-Moresque wares were exported, either directly or via the Balearic Islands to Italy and the rest of Europe. This type of Spanish pottery owed much to its Moorish inheritance, in Italy, locally produced tin-glazed earthenwares, initiated in the fourteenth century, reached a peak in the late fifteenth and early sixteenth centuries. The first northerners to imitate the tin-glazed earthenwares being imported from Italy were the Dutch, English Delftware produced in Lambeth, and at other centers, from the late sixteenth century, provided apothecaries with jars for wet and dry drugs. Many of the potters in London were Flemish. By about 1600, blue-and-white wares were being produced, labelling the contents within decorative borders, the production was slowly superseded in the second half of the eighteenth century with the introduction of cheap creamware.
Dutch potters in northern Germany established German centres of faience, the first manufactories in Germany were opened at Hanau and Heusenstamm, in Switzerland, Zunfthaus zur Meisen near Fraumünster church houses the porcelain and faience collection of the Swiss National Museum in Zurich. Faïence parlante bears mottoes often on decorative labels or banners, wares for apothecaries, including albarello, can bear the names of their intended contents, generally in Latin and often so abbreviated to be unrecognizable to the untutored eye. Mottoes of fellowships and associations became popular in the 18th century, at the low end of the market, local manufactories continued to supply regional markets with coarse and simple wares. These so-called majolica wares were made by Wedgwood and numerous smaller Staffordshire potteries round Burslem
Delftware or Delft pottery, known as Delft Blue, is blue and white pottery made in and around Delft in the Netherlands and the tin-glazed pottery made in the Netherlands from the 16th century. Delftware in the sense is one of the types of tin-glazed earthenware or faience in which a white glaze is applied. It forms part of the family of blue and white pottery, using variations of the plant-based decoration first developed in 14th century Chinese porcelain. Delftware includes pottery objects of all such as plates, ornaments. The most highly-regarded period of production is about 1640–1740, the earliest tin-glazed pottery in the Netherlands was made in Antwerp where the Italian potter Guido da Savino settled in 1500. The manufacture of painted pottery spread from Antwerp to the northern Netherlands, production developed in Middelburg and Haarlem in the 1570s and in Amsterdam in the 1580s. Much of the work was produced in Delft, but simple everyday tin-glazed pottery was made in places such as Gouda, Amsterdam.
The main period of pottery in the Netherlands was 1640–1740. From about 1640 Delft potters began using personal monograms and distinctive factory marks. The Guild of St Luke, to which painters in all media had to belong, the Double Tankard, The Young Moors Head, and The Three Bells. The use of marl, a type of rich in calcium compounds, allowed the Dutch potters to refine their technique. The usual clay body of Delftware was a blend of three clays, one local, one from Tournai and one from the Rhineland. From about 1615, the potters began to coat their pots completely in white tin glaze instead of covering only the painting surface and coating the rest with clear ceramic glaze. They began to cover the tin-glaze with clear glaze, which gave depth to the surface and smoothness to cobalt blues. During the Dutch Golden Age, the Dutch East India Company had a trade with the East. The Chinese workmanship and attention to detail impressed many, only the richest could afford the early imports. Dutch potters did not immediately imitate Chinese porcelain, they began to do so after the death of the Wanli Emperor in 1620, potters now saw an opportunity to produce a cheap alternative for Chinese porcelain.
After much experimenting they managed to make a type of earthenware which was covered with a white tin glaze
Quartz is the second most abundant mineral in Earths continental crust, behind feldspar. There are many different varieties of quartz, several of which are semi-precious gemstones, since antiquity, varieties of quartz have been the most commonly used minerals in the making of jewelry and hardstone carvings, especially in Eurasia. The word quartz is derived from the German word Quarz and its Middle High German ancestor twarc, the Ancient Greeks referred to quartz as κρύσταλλος derived from the Ancient Greek κρύος meaning icy cold, because some philosophers apparently believed the mineral to be a form of supercooled ice. Today, the rock crystal is sometimes used as an alternative name for the purest form of quartz. Quartz belongs to the crystal system. The ideal crystal shape is a six-sided prism terminating with six-sided pyramids at each end, well-formed crystals typically form in a bed that has unconstrained growth into a void, usually the crystals are attached at the other end to a matrix and only one termination pyramid is present.
However, doubly terminated crystals do occur where they develop freely without attachment, a quartz geode is such a situation where the void is approximately spherical in shape, lined with a bed of crystals pointing inward. α-quartz crystallizes in the crystal system, space group P3121 and P3221 respectively. β-quartz belongs to the system, space group P6222 and P6422. These space groups are truly chiral, both α-quartz and β-quartz are examples of chiral crystal structures composed of achiral building blocks. The transformation between α- and β-quartz only involves a comparatively minor rotation of the tetrahedra with respect to one another, although many of the varietal names historically arose from the color of the mineral, current scientific naming schemes refer primarily to the microstructure of the mineral. Color is an identifier for the cryptocrystalline minerals, although it is a primary identifier for the macrocrystalline varieties. Pure quartz, traditionally called rock crystal or clear quartz, is colorless and transparent or translucent, common colored varieties include citrine, rose quartz, smoky quartz, milky quartz, and others.
The most important distinction between types of quartz is that of macrocrystalline and the microcrystalline or cryptocrystalline varieties, the cryptocrystalline varieties are either translucent or mostly opaque, while the transparent varieties tend to be macrocrystalline. Chalcedony is a form of silica consisting of fine intergrowths of both quartz, and its monoclinic polymorph moganite. Other opaque gemstone varieties of quartz, or mixed rocks including quartz, often including contrasting bands or patterns of color, are agate, carnelian or sard, heliotrope, amethyst is a form of quartz that ranges from a bright to dark or dull purple color. The worlds largest deposits of amethysts can be found in Brazil, Uruguay, France, sometimes amethyst and citrine are found growing in the same crystal. It is referred to as ametrine, an amethyst is formed when there is iron in the area where it was formed
Sancai is a versatile type of decoration on Chinese pottery mainly using the three colors of brown, and a creamy off-white for decoration. It is particularly associated with the Tang Dynasty and its tomb figures, therefore, it is commonly referred to as Chinese, 唐三彩 Tang Sancai in Chinese. Flatware dishes and other vessels were made in the technique as well as figures, the body of sancai ceramics was made of white clay, coated with colored glaze, and fired at a temperature of 800 degrees Celsius. Sancai is a type of lead-glazed earthenware, lead oxide was the principal flux in the glaze, the polychrome effect was obtained by using as coloring agents copper and less often manganese and cobalt. Sancai follows the development of green-glazed pottery dating back to the Han period, predecessors to the sancai style can be seen in some Northern Qi ceramic works. Northern Qi tombs have revealed some beautiful artifacts, such as porcellaneous ware with splashed green designs, such a jar has been found in a Northern Qi tomb, which was closed in 576 AD, and is considered as a precursor of the Tang sancai style of ceramics.
The sancai technique dates back to the Tang Dynasty, the colors of the glazes used to decorate the wares of the Tang Dynasty generally were not limited to three in number. In the West, Tang sancai wares were sometimes referred to as egg-and-spinach by dealers, for their use of green, Sancai wares were northern wares made using white and buff-firing secondary kaolins and fire clays. At kiln sites located at Tongchuan, Neiqui county in Hebei and Gongxian in Henan, the burial wares were fired at a lower temperature than contemporaneous whitewares. Large figures made for goods in burials, such as the well-known representations of camels and horses, were cast in sections. In some cases, a degree of individuality was imparted to the figurines by hand-carving. Sancai continued to be produced in periods, very often for large items made for temples, sets of sancai luohan figures up to life-size were often displayed in special luohan halls in temples. Few of these remained in place survived the Cultural Revolution.
The Yixian glazed pottery luohans are a Liao dynasty set that is now distributed between various Western museums, and so well known. Unusually, these were constructed around internal supporting iron bars, pairs of large guardian figures flanking shrines were made. Sancai travelled along the Silk Road, to be extensively used in Syrian, Cypriot. Sancai became a style in Japanese and other East Asian ceramic arts. In the 1980s and early 1990s reproductions of Tang sancai pieces were sent by the Chinese government to foreign leaders as gifts, at one point there were more than 3,000 factories, mostly tiny and shabby, sprinkled around Luoyang City, cradle of the craft
The Etruscan civilization is the modern name given to a powerful and wealthy civilization of ancient Italy in the area corresponding roughly to Tuscany, western Umbria, and northern Lazio. Culture that is identifiably Etruscan developed in Italy after about 800 BC, the latter gave way in the 7th century BC to a culture that was influenced by ancient Greece, Magna Graecia, and Phoenicia. The decline was gradual, but by 500 BC the political destiny of Italy had passed out of Etruscan hands, the last Etruscan cities were formally absorbed by Rome around 100 BC. Politics were based on the city, and probably the family unit. In their heyday, the Etruscan elite grew very rich through trade with the Celtic world to the north and the Greeks to the south, archaic Greece had a huge influence on their art and architecture, and Greek mythology was evidently very familiar to them. The study excluded recent Anatolian connection, the ancient Romans referred to the Etruscans as the Tuscī or Etruscī. Their Roman name is the origin of the terms Tuscany, which refers to their heartland, and Etruria, which can refer to their wider region.
In Attic Greek, the Etruscans were known as Tyrrhenians, from which the Romans derived the names Tyrrhēnī, Tyrrhēnia, the word may be related to the Hittite Taruisa. The Etruscans called themselves Rasenna, which was syncopated to Rasna or Raśna, the origins of the Etruscans are mostly lost in prehistory, although Greek historians as early as the 5th century BC, repeatedly associated the Tyrrhenians with Pelasgians. Strabo as well as the Homeric Hymn to Dionysus make mention of the Tyrrhenians as pirates, pliny the Elder put the Etruscans in the context of the Rhaetian people to the north and wrote in his Natural History, Adjoining these the Noricans are the Raeti and Vindelici. All are divided into a number of states, the Raeti are believed to be people of Tuscan race driven out by the Gauls, their leader was named Raetus. Historians have no literature and no original Etruscan texts of religion or philosophy, much of what is known about this civilization is derived from grave goods, another source of genetic data on Etruscan origins is from four ancient breeds of cattle.
Analyzing the mitochondrial DNA of these and seven other breeds of Italian cattle, the other Italian breeds were linked to northern Europe. Etruscan expansion was focused both to the north beyond the Apennine Mountains and into Campania, some small towns in the sixth century BC disappeared during this time, ostensibly consumed by greater, more powerful neighbours. However, it is certain that the structure of the Etruscan culture was similar to, albeit more aristocratic than. The mining and commerce of metal, especially copper and iron, led to an enrichment of the Etruscans and to the expansion of their influence in the Italian peninsula and the western Mediterranean Sea. Here, their interests collided with those of the Greeks, especially in the sixth century BC and this led the Etruscans to ally themselves with Carthage, whose interests collided with the Greeks. Around 540 BC, the Battle of Alalia led to a new distribution of power in the western Mediterranean, from the first half of the 5th century BC, the new political situation meant the beginning of the Etruscan decline after losing their southern provinces
Raku ware is a type of Japanese pottery traditionally used in Japanese tea ceremonies, most often in the form of chawan tea bowls. In the traditional Japanese process, the raku piece is removed from the hot kiln and is allowed to cool in the open air. The familiar technique of placing the ware in a filled with combustible material is not a traditional Raku practice. Raku techniques have been modified by contemporary potters worldwide, Raku means enjoyment, comfort or ease and is derived from Jurakudai, the name of a palace, in Kyoto, that was built by Toyotomi Hideyoshi, who was the leading warrior statesman of the time. The resulting tea bowls made by Chōjirō were initially referred to as ima-yaki and were distinguished as Juraku-yaki. Hideyoshi presented Jokei, Chōjirōs son, with a seal that bore the Chinese character for raku, Raku became the name of the family that produced the wares. Both the name and the style have been passed down through the family to the present 15th generation. The name and the style of ware has become influential in both Japanese culture and literature, in Japan, there are branch kilns, in the raku-ware tradition, that have been founded by Raku-family members or porters who apprenticed at the head familys studio.
One of the most well-known of these is Ōhi-yaki, other famous Japanese clay artists of this period include Dōnyū, Honami Kōetsu and Ogata Kenzan. In the western style of raku firing, the aluminium container acts as a reduction chamber, a reduction atmosphere is created by closing the container. A reduction atmosphere induces a reaction between oxygen and the minerals, which affects the color. It affects the metal elements of the glaze, Reduction is a decrease in oxidation number. Closing the can reduces the content after the combustible materials such as sawdust catch fire and forces the reaction to pull oxygen from the glazes. For example, luster gets its color from deprivation of oxygen, the reduction agent is a substance from which electrons are being taken by another substance. The reaction uses oxygen from the atmosphere within the reduction tube and this leaves ions and iridescent luster behind. Pieces with no glaze have nowhere to get the oxygen from and this atmosphere will turn clay black, making a matte color.
Reduction firing is when the atmosphere, which is full of combustible material, is heated up. Reduction is incomplete combustion of fuel, caused by a shortage of oxygen and this draws oxygen from the glaze and the clay to allow the reaction to continue