DELFTWARE 

The term ' delftware' is generally used to indicate functional or ornamental earthenware pottery covered with white tin glaze on which decorations have been painted in blue, purple, or other colours. The term is derived from the Dutch town of Delft,where from the seventeenth century many potteries produced hand-painted tin-glazed pottery of high quality which was exported all over the world. The potteries in Delft produced tiles alongside their other wares but tiles were not a major product. Most Dutch tiles were produced in factories in such places as Rotterdam, Harlingen , Makkum and Utrecht, where tiles were the main line of business. Delftware was also made in Britain. at first by Dutch potters who emigrated in the seventeenth century. 

Their primary purpose was functional but the many scenes and decorations painted on them have made them a fascinating field of study, which is one of the main reasons why they are now eagerly collected or carefully preserved in situ.

MANUFACTURING PROCESSES

The basic method of making and decorating delftware tiles is as follows. Prepared clay is rolled into flat slabs from which rough squares are cut. The squares are put into wooden or iron frames and the clay is levelled within the square frame .

When the frame is lifted, a perfect square has been formed. After a period of drying, the tiles have to be rolled and flattened again , but as they lose their shape they have to be trimmed square again. This is done with the aid of a square wooden board which is placed on the tile and any excess clay is cut away from around the board. The tile is left to dry again, after which it will be fired for the first time at a temperature of about 1000 C (1800 F).

After the first firing, the tiles are sorted and glazed. The liquid tin glaze is applied to one side of the tile and when the liquid has evaporated a firm thin layer of a white powder-like substance is left. The tile is then passed to the painter, who places a transfer pricked with a particular pattern or design on the unfired white glaze and pounces charcoal through the holes pricked in the transfer. When this is removed a faint outline of the design can be seen. The painter then outlines the design with a dark colour (usually blue or purple), after which the various tints and shades are added. Corner motifs were often painted by apprentices.) When the tile has been decorated it is fired a second time at a temperature of about 1000 C (1 800 F) , during which the powder-like tin glaze becomes white, opaque and glassy. The blue (or other high temperature colour) pigment sinks into the tin glaze and fuses permanently with it.

Although the basic procedure outlined here seems simple, much experience and great skill are needed to complete each phase satisfactorily and the success of the delftware tile trade depended (and still does) on the expertise being passed on without break from master to apprentice.

ENGLISH DELFTWARE TILES

The art of making tin-glazed tiles was brought to England by Flemish and Dutch potters. Jasper Andries and Jacob Jansen had moved from the Low Countries to Norwich by 1567

In 1570 Jacob Jansen went to London, where he unsuccessfully petitioned Queen Elizabeth I to be allowed to make tin-glazed floor tiles. The potteries in London that made delftware during the seventeenth century occasionally produced tiles, but it seems likely that they were made by Dutch potters who had settled there. Jan Ariens van Hamme, for example, was granted permission to make delftware pottery and tiles in 1676. Compared to production in Holland at the time, the output of delftware tiles in England was insignificant and so many tiles had to be imported from Holland despite an import ban imposed on Dutch delftware in 1672.

The English delftware tile industry did not become established until the eighteenth century. The main centres of production were London , Bristol, and Liverpool. Some tiles were also produced in Scotland, at the Delftfield factory in Glasgow, in the middle of the eighteenth century. Until 1750 English delftware tiles were closely based on Dutch examples and English tilemakers copied such Dutch subjects as biblical scenes, landscapes, flower vases, and shepherds painted in blue or purple. It is clear that the aim of the English tilemaker was to manufacture tiles that were indistinguishable from Dutch tiles in order to compete with them. This is particularly noticeable in biblical and landscapes tiles, where borders and central scenes closely follow Dutch examples, although differences between Dutch and English tiles can be detected in the way they are painted and in the composition of the tin glaze and the clay of the tile body. The tin glaze on Dutch tiles is usually whiter because it contains more tin oxide, although it is liable to craze. English tin glaze has a higher lead content and is often somewhat bluish and much glossier and smoother than Dutch glaze and it does not craze easily.