The Manufacture of Delftware

Types of Wares A wide variety of items were made.  These include plates, dishes, tiles, bowls, bottles, mugs, chargers, posset pots, puzzle jugs, vases, flower bricks, flower pockets, drug jars, ointment pots, bleeding bowls, barbers bowls, tea and coffee wares.  Plates, dishes and tiles are the most commonly surviving items.  Very few undecorated pieces survive, although they were produced in large numbers. A charger was a decorative dish, shaped in a continuous curve from side to side.  There is a small foot-rim, which may have two holes in it, used to hang the piece on a wall.  Many chargers have blue dashes around the edges.  Today any large dish is often described as a charger, but this is incorrect.  The charger was a shape originally used on Islamic food dishes, going back to at least the 14th century.  Why it was still being made in 18th century England is a bit of a mystery.   Posset was a drink made from curdled milk, some alcoholic beverage, and spices (sounds horrible!). Surviving pieces often have considerable damage.  Both the pottery and the glaze are brittle.  The glaze is frequently fritted away from part of the rim.  In addition, tin glaze will not withstand boiling water, so there may be original damage on tea and coffee wares.

Manufacture The tin glaze will only adhere to a porous body, so delftware was made from a mixture of two clays.  One was a local red clay, the other was an estuary clay containing a high proportion of chalk.  They were referred to as fat and lean clays respectively.  London obtained their lean clay from East Anglia or Kent, the other factories from Carrickfergus in Ireland. The piece would either be thrown on the potter's wheel or moulded.  Tiles were formed by rolling.  Then it would be given an initial (biscuit) firing in the kiln.  During this stage the chalk burns off, leaving a porous body, and bleaching the body to a buff color.  It would then be glazed, the glaze left to dry and then painted.  It would be finally fired in the kiln again.  Plates and dishes were supported, in the saggars, by three clay pegs, around the rim, this leaves marks on the underside of pieces.  Chargers were fired upside-down, the face of an upper one being separated from the foot-rim of a lower one by a trivet.  This leaves three marks on the faces of chargers.  The manufacturing process resulted in many imperfect pieces, which could not be sold at the full price.  Although Captain Delamain, in Dublin,  had used coal for the kiln fuel in the 1750s other delftware potters continued to use wood, which was more expensive than coal. Decorating on an unfired glaze leaves no room for error, as the paint immediately starts to sink into the glaze.  However, the glaze could be stabilized with gum arabic or covered with lacquer, making the painting process much easier and the piece could be painted before the glaze was added (at least with blue).  The decorator might be helped by pouncing the design.  In pouncing the outline of the design is drawn onto paper or card and then pricked through with a pin, powdered charcoal or soot is brushed through the holes to transfer the outline to the piece.  The charcoal, or soot, burns off in the kiln leaving no trace.  Pigments were made from metal oxides: cobalt for blue, manganese for purple or black; iron for red; antimony for yellow; and copper for green.  Green could also be mixed from blue and yellow.  Red does not appear until the early 18th century.  Much surviving decoration is in blue only.  The Delftfield case gives an idea of how a pottery was organised.  When decorating the manager, or clerk, would select a design which the painters would copy.  These copies were not exact, explaining the wide variations in surviving specimens.  In 1756 John Sadler invented a method of transfer printing.  It was used, but only in Liverpool, to print tiles.  Sadler's printing was also applied to Staffordshire creamware.

Decorative Styles Early English delftware tended to be similar to Dutch.  During the latter part of the 17th century a different style evolved, often referred as English maiolica.  Notable examples of this are the royal portrait chargers.  Chinese designs were copied, but by the end of the 17th century the copies were often far removed from the originals.  Much surviving delftware has 'chinoserie' decoration.  Published prints provided the source for some decoration, for example Robert Sayer's 'The Ladies Amusement' c1760.  Animals were popular, particularly around 1730.  Some of the best decoration, at Bristol, centered around landscapes and the bianco-sopra-bianco border. Glazes may have a blue or green tinge.  Some late Bristol pieces have a delightful lavender glaze.  17th century pieces sometimes have a clear glaze on the back (copied from European and earlier Islamic practice).  18th century chargers can have a white glaze on the front and a light green glaze on the back.  Dutch pieces have an additional clear glaze (a kwaart) on top of the decoration, resulting in a glassy appearance.  This can occur with English pieces, but is rare.  Pin-holes are very common in the glaze, on the back of plates and dishes, particularly those made before 1750.  Later pieces often have a white slip under the glaze, which gives a better finish.  A similar white dip was used on Staffordshire stoneware, from about 1710.

Marks Some plates and dishes have markings under the rim.  They are of two types, noughts and crosses and botanical.   The former is of the type // O (and similar motifs), usually repeated four times, and may denote Bristol manufacture (some pieces attributed to Lambeth also have similar marks).  The latter are of various types - herbal sprigs, edge grasses, almond branches, etc.  Herbal sprigs are generally associated with Liverpool and Dublin; edge grasses and almond branches with Bristol.  To associate an under-rim mark to a place of manufacture can be dangerous, unless some other evidence is present.  Both types are copied from Chinise porcelain, noughts and crosses from the earlier Ming pieces.  Noughts and crosses also appear on some Dutch 17th century items and these may be passed off as Bristol 18th century pieces Within the foot-rim there may be a number, initials, a leaf design, and very rarely an inscription.  The first two probably refer to the decorator, within the factory. Many inscribed and dated pieces survive, helping to date similar designs.