How was Delftware made?

A pottery Dutch term for a pottery producing lead- and tin-glazed earthenware (majolica and faience). pottery would therefore usually be a large complex with one or more kilns for firing the pots. Other facilities were also needed on site: drying lofts (droogzolders), woodsheds, warehouses and a salesroom. Proprietors would often have their home on the complex, too.

Everyone at the pottery had their own specialisation and was responsible for a particular part of the production process.

The most elaborate description of the production of Delftware was captured at the end of the eighteenth century by the patriotic writer Gerrit Paape, who had worked in a pottery as a child. The illustrations on this page are all part of his book 'De plateelbakker of Delftsch aardewerkmaaker'  ('The potter or Delftware maker', 1794).

Mixing the clay

The clay for Dutch delftware consisted of several kinds: local clay, fattier clay from Germany and dry marl Adding earth from Tournai (known in Dutch as Doornikse aarde) to clay produced a pale yellow body. marl from the Tournai region of Flanders or England. This combination allowed thin earthenware objects to be made. The clays were mixed and purified in a clay washery – an independent enterprise that would supply several potteries.

The pottery would store square blocks of clay in pits

The washery would add water to the clay to mix the different types. The thin suspension would then be passed through a copper sieve and caught in trays where it dried and stiffened. Once the clay was dry it would be cut into square blocks and taken to the pottery, where it would be stored in pits.

Earth treader

At the pottery the clay had to be made soft and pliable again, of course. This was the job of the aardetrapper (literally, ‘earth treader’), who would knead the clay with his bare feet.

Throwing and shaping

The softened clay would go to the throwers (draaiers) and shapers (vormers), who would turn it into objects. Throwers used the potter’s wheel to produce dishes and other circular items. Other shapes, and items that consisted of several parts, such as vases and animal figurines, would be made by the shapers. They used plaster moulds to repeat a shape. Components like knobs and handles would be shaped by hand and stuck on using clay slurry Liquid clay used as an adhesive to stick together the different parts of an object during the production process. clay slurry (kles).

Separate components would be stuck onto the object using clay slurry

At this point the pieces still contained a lot of water, so they had to be dried in the drying loft, otherwise the clay would fracture in the kiln. Once it was dry the shaper could make any necessary adjustments.

Initial firing

Before being glazed, the pots were given an initial firing The initial firing of unglazed earthenware, which produces biscuit wares. initial firing . Stokers would heat the kiln to 800-1000° C. The wares became hard and buff-coloured during firing. They were now known as 'ruw gebakken goed’ (literally, ‘rough fired wares’). These days the term 'biscuit Unglazed earthenware that has been fired once. biscuit ' is also used in both Dutch and English.

Glazes

Gevers (literally, ‘givers’) would scrub the rough fired wares clean and dip them in a bath of tin glaze Tub containing tin glaze into which the wares (biscuit) are dipped after the first firing, creating a white surface to which the painter can then apply the decoration.   a bath of tin glaze . This mix of lead, tin, sand, soda and salt would first be fired in the kiln to make a vitreous plate, then ground in a paint mill.

If the pots were to be plain white, they were now ready for the second firing. Or they could be painted, by the plateelschilder Dutch term for a painter specially trained to decorate earthenware. plateelschilder .

Painter

The plateelschilder painted by hand, or use a pounce Paper on which the outlines of a decorative design have been pricked out. The design is transferred to the object through the holes using powdered charcoal. pounce (spons – a piece of paper with perforations) to apply dotted lines of charcoal to the object, which he could then paint over. This was a good way of transferring the same patterns and pictures to several objects.

The grey pigment turned bright blue in the kiln

The famous blue pigment is a cobalt oxide mined in Germany. When painted on it would be dark grey, but this would change to bright blue in the kiln. The purer the cobalt, the brighter the blue. To give objects extra gloss, they could then be covered with a layer of transparant lead glaze A transparent glaze whose main component is lead oxide. transparant lead glaze , in a process known as kwaarten Traditional Dutch term for the application of a top layer of transparent lead glaze (kwaart) to produce a brilliantly shiny surface. Also known as coperta. kwaarten .

Second firing

Now all the objects could be returned to the kiln for the second ‘glaze’ or ‘glost’ firing The second firing, designed to fuse the glaze to the surface at a temperature of approx. 1000° C. To prevent objects from fusing together in the kiln, they are separated using spurs or pegs and saggars. ‘glaze’ or ‘glost’ firing . They would be placed in earthenware saggars A cylindrical earthenware container in which earthenware objects would be stacked for firing. To prevent the objects from fusing to the surface, each one would rest on triangular pegs inserted through the wall of the saggar. To protect the pots from kiln fumes, the saggar was closed during firing by placing tiles on top and underneath. saggars to ensure that they were not damaged by flames or fumes. Inside the saggars the pots were separated by pegs, to stop them from fusing together. After this firing, they pots would be smooth.

It would take several days for the pots to be fired and cooled. If the kiln was too hot the earthenware could become misshapen. If it cooled too fast cracks could appear. The pieces were therefore inspected and sorted into top quality (‘schoongoed’) and seconds ('entredeux’ or ‘wrak'). All manner of things could go wrong during the firing process. There is even a story of a batch of Delft blue that came out green!

Third firing

Many colours could be applied before the second firing, which used the grand feu technique. But the temperature was so high that gold, red and black would burn away. They were therefore applied after the second firing. The pots would then go into the kiln for a third time, at 600 degrees Celsius – the petit feu technique. This part of the process was sometimes carried out by homeworkers using small muffle kilns Small kiln used to fire smaller batches of pots. Some gilders had kilns of this type on the premises, presumably to fire gilded pieces using the petit feu technique. Hence the Dutch term ‘goudschilderoven’ (= gilder’s kiln). muffle kilns .