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The purpose of this resource is to give you quick answers about pottery terms, definitions, details, techniques, tips, history, science, and art so you can more fully enjoy and even perhaps learn as you proceed through the gallery. Many entries offer links to other more authorative online resourses if you want to go deeper.
montefin's Pottery Glossary.
Albany Slip -- a slip made from clay mined in the vicinity of Albany, New York, USA famous for rich, translucent, chocolaty brown surface decorations. The known, naturally occuring deposits of Albany Slip have almost all been depleted. For a good overview of Albany Slip from the historic, aesthetic and technical viewpoints with some good guidance on Albany substitutes visit http://www.digitalfire.ab.ca/cermat/material/31.html.
Atmosphere -- the chemical make up of the volatilized vapors surrounding the pottery inside a pottery kiln, or within a post firing containment such as is frequently used in raku pottery.
Barnhard's Clay is a high-fire slip which gives burnt metallic tones to the finished surfaces of pots to which it is applied.
Bats are surfaces on which wet clay or pottery is carried or worked upon. Throwing bats are circular disks that can be fitted to the head of a pottery wheel so that finished pieces, particulary broad bottomed pieces such as plates or platters, can be easily lifted off the wheel. Bats can be made of Plaster of Paris, wood, or bakelite.
Bisque is a fired piece (bisquette) of unglazed clay used to make pottery, figurines, dolls, knickknacks, ornaments etc. This porous, vitreous ceramic can be created using heat, which causes a chemical reaction (dehydroxylation) in clay (e.g. kaolinite) to irreversibly change:
If you've ever noticed that some pots look like living, breathing things, you're not far off the mark. From antiquity, potters have given pots lift and vitality by breathing into them while still wet, then pinching the mouth of the pot shut and letting it dry to the leather-hard stage before trimming away the closure and finishing the pot.
To burnish means to polish clay when it is leather-hard. Typically done with a hard object that has a smooth surface, such as a metal spoon or a well worn river stone.
Celadon or Longquan Celadon is a type of pottery having a pale green glaze, originally produced in Longquan city, Zhejiang province, China. The first making of Celadon in Longquan begins in the Jin Dynasty (265-376 B.C.). The Northern Song Dynasty (960-1127 B.C), the most important dynasty in Chinese porcelain history, also brought prosperity in celadon production and appreciation. By the Southern Song and Yuan Dynasty (1127-1368 B.C), Longquan Celadon entered a most prosperous period during which the skill of making celadon had reached a new height and gradually formed a comprehensive celadon kiln system centering on Longquan town.
Longquan Celadon has two types, say, Ge Kiln and Di Kiln (Ge means elder brother and Di means younger brother in Chinese). The former together with Ru Kiln, Jun Kiln, Guan Kiln and Ding Kiln are recited as Five Famous Kilns in Song Dynasty. Famous worldwide, Longquan celadon was not only used for every dynasty's royal courts in ancient China, but exported to many other countries and regions of Asia, Africa and Europe early since the Song Dynasty.
Especially in the middle of the Ming Dynasty Longquan Celadon was introduced into Europe while its price was worth gold. Modern Longquan celadon inherits the products feature of traditional Longquan kiln and has been innovating and developing. Recently, many celadon products made by local masters and craftsmen have won the honors and prizes in various pottery-making competitions. A few of those have built up reputations of the Treasures of the Nation and have been collected in many museums.
The term celadon for these pale Jade-green glazes, is distinctly un-Chinese. In fact the term 'celadon' was applied by European connoisseurs to the wares when they appeared in France in the 17th century. In Honoré d'Urfé's (1567-1625) French pastoral romance, L'Astrée (1627), one of the shepherds was named Celadon, and the refined simplicity of Arcadia was applied to the ceramics.
Ceramics is the craft of creating useful and/or decorative objects from clay. For more info visit www.fact-index.com/c/ce/ceramics.html
Chamois -- extremely smooth and soft leather that, when wet, can be used to soften sharp edges on wet to leather-hard clay pots.
Crackle, also called crazing, is tiny, virtually invisible cracks on the surface of glazed pots. Basically, this happens because the glaze and clay fuse, individually and to each other, at the height of the firing temperature. As the kiln and the pottery cool, the clay body and the glaze shrink together, though at slightly different rates and degrees. If the glaze and clay body have been properly matched, all that happens is that the glaze accomodates the clay by developing this widespread crackle.
If you have ever seen the tiny dark lines in the well of a much loved tea cup that has been used for generations, you've seen crackle made visible by warm tea repeatedly seeping into the minute cracks. Now much loved, much used tea, yea even coffee, vessels have much wabi and much sabi. No wonder that the raku pottery process is steeped in crackle.
But, hey, say you've got a nice stoneware pot that's got a great shape and a great smooth, glistening glaze, and all it needs is for you to bring out that naturally occuring crackle to make it perfect? Got a century or two? Don't dispair, Chinese potters have been burying celadon pots in super strong tea and achieving respectable crackle in a year or two. But, if you're impatiant like me, try this. Get a bottle of plain old India Ink, heat the pot in a warm over, say 200 degrees - just enough to open up that old crackle then smear good old India Ink all over. It dries in moments and you vcan wipe the surface ink off with a damp paper towel exposing a deep, dark permanent crackle. For a good example of India Ink crackle click here page.
dDecorative and finishing techniques
Earthenware is a ceramic made from potash, sand, feldspar and clay, typically fired at a temperature of around 500 degrees Celsius (900 degrees Fahrenheit). Earthenware is typically fired at a temperature of around 500 degrees Celsius (900 degrees Fahrenheit). It is one of the oldest materials used in pottery. Classically, most earthenware has a red coloring, due to the use of iron rich clays. However, this is not always the case, and for the modern potter, white and buff colored earthenware clays are commercially available.
Earthenware may sometimes be as thin as bone china and other porcelains, though it is not translucent and is more easily chipped. Earthernware is also less strong, less tough, and more porous than stoneware - but its low cost and easier working compensate for these deficiencies. Due to it's higher porosity, earthenware must usually be glazed in order to be watertight.
Engobes are liquid clays slips typically applied to pots at the leather-hard or greenware stage to add color, texture, or improve the surface quality for later decoration. For a good overview of engobes visit http://www.ceramicstoday.com/articles/engobes1.htm.
In pottery, glazing is the process of coating the piece with a thin layer of material that becomes not only glassy during firing, but actually glass. This can be achieved by brushing, pouring or dipping on liquid glazes prepared according to usually very precise recipes, or it can be achieved by manipulating the atmosphere within the kiln with additions of substances like ash or salt which in effect actually turns the skin of the clay pottery into glass.
Hump Mold is the process of laying a slab of clay over a shape, the hump, or slapping, paddling or pounding an amount of clay over such a form.
The Jomon period - 10,000 B.C. to 300 B.C. Some of the most fascinating pottery ever made in Japan dates back to the Jomon. The open-pit fired large vessels had the most amazing decorative features and continue to inspire potters today. For more information and photographs visit http://www.e-yakimono.net/html/jomon-dogu.html.
Kilns have been made for as long as there has been pottery and items made of clay. The technology is thus very old. Most likely the first kilns where campfires or open bonfires. Early examples of kilns found in the United Kingdom, include those made for the making of roof-tiles during the Roman occupation. These kilns were built up the side of a slope, such that a fire could be lit at the bottom, and the heat would rise up into the kiln.
There are many kinds of kiln types, but the major division is between fuel burning kilms and electric kilns.
Fuel burning kilns are usually known by the name of their fuel: such as wood fired kiln, gas kiln, etc. Kilns can also be known by the particular type of pottery they're designed or dedicated for, such as a raku kiln or a salt kiln. Kilns can be permanent, re-usable fixtures or one time kilns, for example, kilns built, fired and torn down, or kilns tailored to fit a specific monumental pieces of pottery, or a primitive sheep or cow dung dome kiln in which the fuel itself is the structure of the kiln and does not survive the firing.
There's even talk of a solar kiln for ceramics.
Lead Glaze -- Long before chronic lead poisoning became a public health issue. lead was a popular constituent of ceramic glazes. Some vibrant colors, particularly red and green, can only be achieved with lead glazes. Knowing what we now know, great care must be taken in the application and use of any lead glazed pottery to be used for eating or drinking or food storage, particularly of acidic foodstuffs, i.e. tomato sauces, vinagar, wine, etc.
Great care must also be taken when disposing of lead glazed pottery or shards of all types to assure against contamination of human and wildlife food or water resources.
Leather-hard - describes the stage during drying when a pot can be trimmed, and other, equally leather-hard pieces of clay can be affixed to it by sprigging.
Majolica is named for the Spanish island of Majorca where the production of this functional ceramic earthenware, characterized by ornate decorations over a base of white tin or lead glaze, and under a lustrous clear glaze, reached its pinnacle of quality and beauty. And, yes, you do prounounce the "j" as in "jolly". There's an excellent article on The Art and History of Majolica at http://www.rencentral.com/GSS/lesson11-maiolica.shtml
Overglaze is a partial or complete coating of one or more glazes, often clear or translucent, applied over previous layers of glaze or glazes, called an underglaze, which may or may not be previously fired.
oxidizing atmosphere is an atmosphere rich in oxygen, the major effect of which is to limit the range of colors possible, particularly at high temperatures.
Pinch pots are pots made by forming a ball of clay with just the potter's hands pushing one thumb down into the center of the ball and pinching up the wall while rotating the pot. Simple, but some of the world's most treasured pieces of raku artistry are plain old pich pots.
Plaster of Paris, or simply plaster, is a type of building material based on calcium sulfate hemihydrate, nominally (CaSO4)2. H2O. A large gypsum deposit at Montmartre in Paris is the source of the name. When the dry plaster powder is mixed with water, it re-forms into gypsum, initially as a paste but eventually drying into a solid.
Plaster of Paris is absorbent. This feature is put to good use in pottery as working surfaces on which overly wet clay can be wedged to bring it to a more workable condition. Plaster of Paris is easy to shape and makes a great mold in which or over which (as in hump molding) clay can be shaped into desired forms. For more info visit en.wikipedia.org/wiki/Plaster_of_paris it keeps you interested;
Porcelain is a type of hard pottery. It is white, but mildly translucent, i.e. light shines through in thin sections and can be decorated to provide colour. For more info visit www.fact-index.com/p/po/porcelain.html
All pottery items go through a series of stages during construction.
Raku loosely translates as enjoyment, contentment, pleasure and happiness and these are meant to be embodied in the forms called Raku. Originally, Raku items were utensils for use in the highly ritualized Japanese Tea Ceremony. Now, it is spread around the globe and comes to life in many functional and artistic embodiments.
Sabi adds seeming history and age to wabi also incorporating serenity, melancholy, loneliness, and imperfection - a chip, a crack, an uninetended consequence of process - so that fresh from the fire the pot seems to have lived and maybe lived a very long time ago.
Wabi is a tough nut, particularly among westerners. It's to pottery what umami is to gastronomy: it emanates the natural world; has quiet, understated earthy elegance, it is a coming out or returning into nature but not in a harsh way; like the lotus it keeps you interested;
Wabi-sabi - Some commentators so closely identify sabi with wabi that they talk of wabi-sabi as a one concept.
sSgraffito (as in graffiti), is a surface decoration technique that involves scratching through the wet, damp, leather hard, or even dried clay or a layer of applied slip, glaze, or stain to create texture, imagery, designs, or reveal a different colour underneath. One colour of slip can be fired, before a second is applied prior to scratching, if the base clay is not of the desired colour or texture.
Slabs are flat, thin ( 1/8" to 1/4") sections of clay which are produced by hand or with a mechanical device called a slab roller. Slab built pottery is pottery constructed wholely or mostly from sections of clay slabs.
Underglaze is a decorative technique in which one or more colored glazes are applied to pottery then an overglaze of one or more clear or translucent glazes are applied over them either before or after the first glaze firing.If there are multiple glaze firings, each subsequent glaze firing is done at a lower and lower temperature so that each underlying designs is not affected. For an example of underglaze click Majolica Moroccan Bowls.