Printing and Painting: a glossary

Perhaps a term of abuse rather than a technical term. It describes decoration added, over and above what its makers intended, to a pot that was already decorated. Usually, but not necessarily, this extra decoration was added long after the pot was made. Because the term is used with dangerous looseness, it is better to avoid it and be specific: ‘additional painted decoration added in about…’  It has become a term of abuse because the antique trade has frequently added painted decoration to old pieces in order to increase their market price.

A test case: a Limehouse porcelain teapot was painted in underglaze blue. Limehouse was an early, experimental factory, and the blue ran when the glaze was fired. The pot was not intended to have additional decoration, but when the pot was still brand new, a freelance enameller in London painted over the blue with a different design in enamel colours. Is that pot ‘clobbered’, in the same sense as if it had been redecorated by an antique dealer in 1900? It seems clearer to avoid the term altogether: use ‘redecoration’, but be specific about what and how and when. 

Enameling or Enamelling
The same as overglaze decoration. It can be printed or painted. Many of the early overglaze printers on pottery called themelves enamellers.

Gilding, or gilt decoration
Gilding means covering with a layer of gold. Gilt is another word for gilded. Powdered gold prepared in honey and attached with size was used in the 18th century.  From about 1790 it was replaced with mercury gilding which has a more brassy look than honey gilding. The mixture was painted on with a brush. When the piece was fired, the mercury evaporated, leaving a layer of gold on the pot. This is an overglaze technique.

Many pots are covered with a protective layer of glaze, which is another name for a glass like coating. Typically the glaze is in liquid form and the pot is dipped into it. It is then fired to harden the glaze: this firing is known as the glaze or glost firing.

Ground laying
A technique developed around 1820. A layer of a special oil is brushed on to the biscuit body and left to become sticky. Powdered colour is then dusted on from a piece of cotton wool. The cotton wool must not touch the oiled surface. The depth of colour is built up gradually. The piece is then dried in a hot cupboard until the colour is hard. This method gives a very evenly coloured surface.The decoration is finished by glazing.

Lustre decoration
Since the Middle Ages, Islamic potters had coated pots with metallic oxides, then starved the kiln of oxygen at a key stage in the firing. This ‘reduction firing’ absorbed the oxgygen in the oxide and left pure shiny metal on the surface of the pots, but was difficult and unpredictable in its results. In 1804 an article translated from German showed British potters how to get a metallic shine by chemical means using a normal firing method. Platinum gave a silver or steel lustre, gold gave a pink or copper lustre. This decoration was applied overglaze.

Overglaze or Onglaze or Enameled
Pots decorated after they have had a glaze fired on to them are known as overglaze decorated. This decoration can be printed or painted. It does not have to stand the temperature at which the glaze was fired. Because the colours are fired afterwards, they can be fired at lower temperatures to avoid them blistering or burning off. Before about 1790 most printed or painted decoration that was not blue was overglaze.

Printed and painted
At a time when it was difficult to print in more than one colour, an economical way to get multicolour decoration was to print in one colour then paint over it in a range of other colours.

Overglaze printed, overglaze painted
Some of the earliest printing on porcelain, at Worcester in the 1750s, was designed to be painted over. In this case both the printing and the painting were overglaze. Many others potters followed their lead.

Underglaze printed, overglaze painted
In general potters applied decoration underglaze when they could. It would not wear off because it was protected by the glaze. And if it could be fired with the glaze, it avoided the extra cost of firing it on afterwards. But a pot printed underglaze in blue might need extra colours that would not stand the temperature at which the glaze was fired. They would be painted on afterwards over the glaze and given a separate firing to fix them.

Underglaze printed, underglaze painted
To do all the decoration underglaze gave both the cheapest and the most durable result. But only in the 1790s did the understanding of chemistry make this possible, and the older methods remained in use until at least 1840.

Pots decorated before they receive a glaze are said to be underglaze decorated. This decoration can be printed or painted. It must be able to stand the temperature at which the glaze is fired. Until about 1790 blue was the only colour which would reliably do this without running. Advances in chemistry gradually made other colours available.

A thin layer of usually translucent colour sometimes painted over part of the printed decoration.  It can be either under or over the glaze.