EARTHENWARE Type of pottery with a particular recipe and requiring particular firing conditions. Production earthenware tableware is white or cream coloured. Opaque. Porous with water absorption in the range 6-8%. In common use in the UK, and elsewhere.
Typical earthenware recipe
- 25% China clay
- 25% Ball clay
- 35% Flint
- 15% China stone
Earthenware is not translucent like Bone China or some Porcelain bodies, it is opaque so it does not allow light to pass through it. The first or biscuit firing temperature is 1100°C to 1150°C, glost firing 1050°C to 1100°C.
There are several types of earthenware, including: Creamware, Delftware, Faience, Tin-glazed pottery, Victorian majolica, Raku and Terra cotta.
|Underglaze pink decorated earthenware from Enoch Wedgwood,|
Tunstall, Stoke-on-Trent, England. 1975
EASING AIR In a bottle oven kiln. (more to come).
EASY FIRED Pottery body fault. Clay fired at too low a temperature resulting in high porosity. If bone china is easy fired it looses its translucency. Same as short fired. Under fired.
EAT Potteries dialect word for 'it.'
EDGE LINING Process. The painting of a coloured line or lines around the edge of a pottery article or piece for decoration.
EDINBURGH SINK Sanitaryware. Particular design of fireclay sink. Huge and heavy.
|Twyfords fireclay Edinburgh Sink|
EFFLORESCENCE Unsightly fine and powdery white growth on the surface of bricks or other articles caused by the presence of soluble salts.
EGG SHELLING Glaze fault. The glaze looses its gloss and wondrous shine due to gas bubbling up through the glaze during firing. The broken surface fails to heal during the fire and the egg shell appearance results. In pottery sanitaryware it is sometimes called 'spangling.'
ELECTRICAL PORCELAIN Pottery Body. A type of porcelain used for producing electrical insulators. Recipe usually consists : 30% ball clay, 20% china clay, 25% Quartz, 25% Feldspar. Insulators used for high-voltage power transmission. Covered with a smooth glaze to shed water.
|Electrical Porcelain insulators on display at|
Gladstone Pottery Museum, Longton, Stoke-on-Trent
Making Porcelain Insulators for Power Lines
"The Potter's Wheel" circa 1920 General Electric
"A very early silent documentary showing the process of manufacturing porcelain insulators:
mixing ingredients, moulding, turning, glazing and firing in huge kilns."
|Insulators made by Bullers of Stoke-on-Trent I|
n the clay state ready for firing
Photo: source unknown Date: 1960s
ELECTRIC TUNNEL OVEN Equipment. Continuous tunnel oven for firing biscuit, glost, or decorated pottery, powered by electricity.
|Electric Tunnel Oven - Wedgwood, Barlaston|
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ELERS The Elers Brothers. John-Philip and David Elers were Dutch silversmiths of German extraction who came to England in the late 1680s. By 1693 they had established a pottery at Bradwell Hall in Newcastle-under-Lyme, Staffordshire, where they began applying metalworking techniques to their manufacturing process. The brothers' methods of pottery production and their refining of the raw materials were revolutionary in England.
|Elers red stoneware mug|
Fitzwilliam Museum, Cambridge
ÉMAUX OMBRANTS The Art or Process of flooding transparent coloured glaze over a stamped or itaglio moulded design. The different thicknesses of glaze produce the lights and shades of the picture. Unlike relief moulded tiles the surface of the finished tile is flat.These monochrome moulded tiles are mostly associated with George Cartlidge particularly his portrait tiles. It produces an almost magical effect rather like a hologram in that the image is three dimensional but the surface of the tile is virtually flat. Rather than the glaze being thinner over raised parts of the design the glaze was thicker and the colour deeper on indented parts of the design. The name gives this away as best translated from the French it means 'enamelled shadows'.
The original sculpting of the mould, quality of clay and its pressing were important factors in the creation of this decorative effect however the glaze formulation and its application and handling were paramount. The glaze had to be both of extremely high translucency and strength of colour which on the face of it are irreconcilable aims and have very low viscosity so that it would flow into the hollows. Once these material criteria had been achieved the glaze had to be applied very consistently and the tile had to be perfectly level in the kiln as minimal pooling of the glaze would vastly increase its colour strength. As glaze formulation is the main criteria colours were limited, at first to a narrow range of browns, greens and blues.
ENAMEL Type of applied decoration. Onglaze ceramic colour with low melting point allowing firing at temperatures between 680°C and 900°C. Made from oxides of metals. Some items of glazed earthenware or bone china are embellished by the use of enamel, a very hard and intensely coloured ceramic 'paint', which is applied to the piece using a sable hair brush called a pencil. A good eye is needed as small amounts of enamel paint are dropped onto the item to be decorated and then gently pushed into place with the brush. The brush itself never actually makes contact with the item being decorated since the enamel is made to drop onto the pot allowing it to remain bulbous.
|Raised enamel. Wedgwood, Barlaston, Stoke-on-Trent, England. 1972|
ENAMEL (MUFFLE) KILN Equipment. Decorating department. Most usually a muffle kiln which is constructed in such a way that the products of combustion during the firing process are prevented from making contact with the ware, and thus causing discolouration. The enamel kiln is used to fire pottery after the application of its decoration, onglaze. Usual temperature is 700 - 800°C. During firing the wares are carefully separated and supported by bats and props.
|Placing an enamel muffle oven|
ENAMELLER Occupation. Decorating department. Enamelling shop. Usually female. Highly skilled occupation. The enameller dribbles ceramic colour onto the pot to create the design. Different from free-hand-painting.
ENAMELLING Process. Decorating department. Some items of glazed earthenware or bone china are embellished by the use of enamel, a very hard and intensely coloured ceramic 'paint', which is applied to the piece using a sable hair brush called a pencil. A good eye is needed as small amounts of enamel paint are dropped onto the item to be decorated and then gently pushed into place with the brush. The brush itself never actually makes contact with the item being decorated since the enamel is made to drop onto the pot allowing it to remain bulbous.
ENAMELLED WARE Glost ware which is decorated with pottery colours. After the decoration it has to be fired again to make the colour permanent.
EMBOSSED A raised decoration on the poittery piece created by either applying the embossment or having them in the plaster of Paris mould.
ENCAUSTIC TILES Ceramic tiles with an inlaid geometric pattern of coloured clays.
|Minton encaustic tiles. 1850|
An encaustic or inlaid tile has a design which is reliant upon the contrast of coloured clays within the tile body rather than just as surface decoration. During the Middle Ages this type of tile was frequently used to pave the floors of cathedrals, churches, monastic buildings and royal palaces. Most medieval tiles consisted of a body of red clay with an inlaid design of white clay; a transparent glaze applied to the surface made the body look brown and the white inlaid clay honey‑coloured yellow. During the first half of the nineteenth century the manufacture of encaustic tiles was revived and were made either of plastic clay with slip infills or wholly of dust clay. In the 1840s, Minton & Co and Chamberlain were the first firms to manufacture replicas of medieval tiles successfully. Chamberlain covered their encaustic tiles with a transparent glaze, but Minton devised a method of heightening the effect of the inlaid design with a yellow enamel glaze, leaving the body of the tile unglazed. From 1842 onward Minton began to introduce colours such as blue and green to augment the basic red and yellow. Initially encaustic tiles were used mainly in churches but during the second half of the nineteenth century their use was extended to civic, public and domestic buildings.
|Minton Encaustic Tiles in the roof of Bethesda Terrace, Central Park, New York City. October 2013|
Photo by the author (it was a great trip!)
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ENGINE TURNING LATHE Equipment. Machine. Lathe with an eccentric motion built in to it. Used to incise decoration into the cheese hard clay piece.
ENGINE TURNING Process. Potting Department. Cheese-hard or leather-hard clay can be turned and cut into perfectly symmetrical items using a variety of tools on a rotating horizontal lathe. A variety of patterns can be ‘diced’ and cut into the clay and the final piece can be covered in complex patterning.
ENGLISH PINK Material. Used in glazes. First used in England in the 18th Century. The colour is formed by the the precipitation of fine particles of chromic oxide onto the surface of tin oxide in opaque glaze. Lime needs to be present
ENGLISH TRANSLUCENT CHINA Type of pottery with a particular recipe and requiring particular firing conditions. English Translucent China. Product of the Royal Doulton Company, (Doulton Fine China) introduced in 1959. Thin and feldspathic translucent porcelain. Differs from 'continental' porcelain since it is biscuit fired at a higher temperature than the glost fire. Renamed in 1973 as Fine China. Contains no bone, as in Bone China. Interestingly the vegetarian movement favoured this product at the start of the 21st Century.
ENGOBE Material used during the process. An intermediate layer. Usually a coloured clay mixed with water to create a thin clay slip. Can be used as decoration either under or on top of the glaze before firing. Can also be used to mask undesirable features in the clay to which it is applied. Common on the manufacture of fireclay sanitaryware as a white intermediate layer - like undercoat.
The engobe contains:
- 5 - 15% ball clay
- 30 - 50% china clay
- 15 - 30% ﬂint
- 20 - 35% china stone
- 0 - 10%, feldspar; the proportions of china stone and feldspar vary inversely as one another.
ENGRAVER Occupation. Decorating department. See what he does below.
|An engraver at Spode 2001|
ENGRAVING Process. Decorating department. The highly skilled process of cutting a decorative design onto a copper plate from which prints are subsequently taken for application to the pottery piece. Created using sharp engraving tools or 'gravers.' The incised pattern is filled with ceramic colour pigments mixed with oils, then transferred to pottery ware by transfer tissue paper.
ENGRAVING AND TRANSFERRING AT SPODESpode’s engravers have always been considered amongst the best in the industry. In 1820, at the height of production of new engraved designs, there would have been hundreds of engravers working on Spode patterns both on-site and in small independent workshops scattered throughout the Potteries. Think about that - hundreds! The training was lengthy and demanding. For most of the first year, apprentices had to patiently engrave squares of straight lines before they are considered good enough to go on to actual patterns.Traditionally, the apprentices trained from age 15 to 21. Although since the 1970s this has been cut to 3 to 4 years, the training remains rigorous. In the 21st Century the occupation is becoming very rare.
|An engraver at Spode 1960|
Fitting the patternThe skill of the engraver’s art does not stop with the ability to engrave designs onto a flat copper plate. Once the design is made the problem arises of transferring the two dimensional image onto a three dimensional pot! This is where 'fitting' comes in.
When asked to create a new copper for a new shape of pot, the engraver must first create a 'fit'. This involves taking careful measurements of the pot and cutting tissue paper pieces to fit the various surfaces of its shape. The tissue fits are then flattened out and the design or part of the design adapted to suit the relevant area. In order to ensure that all the necessary separate pieces are kept together for a particular shape, the engraving for all the areas of the pot are sometimes engraved onto one flat copper plate or, in some cases, onto a roller, an engraved cylinder of copper. Roller engraving was introduced at Spode in 1837. The method saved money, since a continuous sheet of transfer prints can be printed at one time, the required set of prints is cut for each object as needed. As can be imagined, engraving the curved surface of the cylindrical roller tests the skill of the engraver even further!
|Engraving tools of the trade|
The tools of the trade
- Flat copper plate or copper roller cylinder
- Punches and rack
- Needle for drawing the outline pattern
- Burins or gravers for engraving the image
- Oil rubber for cleaning the copper
- Hammer for punch work
- Magnifying glass
- Scraper to remove burrs
- Tissue 'pull'
Hot press, flat plate, printing and transferringThese are the principal stages required in producing an engraved decorative design - from the application of the colour to the engraved copper plate, through to the glost firing of the pottery piece.
- An engraved copper plate, containing the decorative design, is warmed over a hot stove, sometimes called a backstun.
- Ceramic colour (a mixture of ceramic pigment and thick sticky oil) is spread over the surface of the copper plate and rubbed into the engraved lines with a wooden dabber. Because the copper plate had been warmed the oil mixture flows more easily into the engraving.
- Most of the excess colour is carefully scraped/wiped off the copper plate.
- The copper is bossed to remove the last remains of excess colour from the surface leaving the colour only in the engraved design.
- Damp, special, tissue paper, previously 'sized' with soft soap and water, is placed on the copper plate.
- The copper and the paper are rolled through a press, together. The roller, on the press, is covered with felt, which helps to force the paper into the engraving.
- The coloured design becomes transferred from the copper to the tissue.
- The copper plate is warmed on the stove again and the tissue paper print is carefully peeled away from the plate. As it is peeled away the tissue takes with it the colour from the engraving. This is called a pull.
- The parts of the print required for each part of each pot are carefully cut from the printed tissue paper pull.
- The paper transfer is skilfully applied to the biscuit fired pot. Centres are applied first, borders afterwards. The tissue is rubbed into place
- The tissue pull, having been rubbed down vigorously onto the pot, using a stiff bristled brush and soft soap, is then washed off with water leaving only the printed image behind on the surface of the pot.
- The print is hardened on in a low temperature firing of about 650-700°C.
- The pot is dipped in glaze. The hardening on enables the piece to be glazed without damaging the decoration.
- The pot is finally fired to 1070°C in the glost oven. The silica in the glaze reacts with the cobalt colour of the decoration to create Spode’s world famous lustrous blue.
PLUCK and DUST, sometimes called PULL and DUST This is a variant to the process described above. The mixture of colour pigment and oil which is spread over the surface of the copper plate, prior to printing the design, has a low percentage colour content. Subsequently the engraved design which had been transferred to the pot needed strengthening. Once the tissue paper had been peeled off the pot, powdered pigment was lightly dusted onto it. The pigment stuck to the sticky oily design.
ER IN DOORS Wife. See below.
ERSFAL Dialect. The wife has fallen over. Aww!
ESS Dialect. Found in an essole.
ESSOLE Potter's name for the ash pit underneath the firemouth in an oven. Same as S Hole. Also Potteries dialect word. "S Hole is simply a dialect way of saying ash hole [found in coal fires in domestic premises] rather than a specifically industrial word." Many thanks to Brian Jones for this update 18 March 2016
ETC Type of pottery with a particular body recipe and requiring particular firing conditions. English Translucent China. Product of the Royal Doulton Company, (Doulton Fine China) introduced in 1959. Thin and feldspathic translucent porcelain. Differs from 'continental' porcelain since it is biscuit fired at a higher temperature than the glost fire. Renamed in 1973 as Fine China. Contains no bone, as in Bone China. Interestingly the vegetarian movement favoured this product at the start of the 21st Century.
ETRURIA MARL Material. Red clay. Found in the Staffordshire Potteries.
EVER LIKELY Dialect. Not surprising, really. No wonder.
EWE NEON MON Dialect. Occupation. Turn to him with all your employment troubles!
EXTRUDER Equipment. Machine which forces soft 'plastic' clay through a die to produce extruded clay shapes.
EXTRUSION Process. Forcing plastic clay through a metal die to create a continuous shape. The extruder uses an auger. The machine used is called a pug or a stupid.
EYE TICE Dialect. Outhouse. Outside lavvy at the bottom of the yard.
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