The production process of Delft earthenware starts with the composition of the clay. It is made up of about 10 raw materials (for example kaolin, chalk, feldspar and quartz). The raw materials are carefully mixed according to special recipes until they form a liquid mass.
Restrike Ducaton in Delft Blue coin holder
In 2019, Rembrandt and the Golden Age were celebrated in the Netherlands. As two centuries-old companies, both of which originated from craftsmanship, Royal Delft and the Royal Dutch Mint joined forces. Together they took you on a journey into the rich history of the Netherlands in the Golden Age with a beautiful issue in a very exclusive Delft Blue coin holder. On this page you can discover how this unique, hand-painted coin holder was manufactured. The painting on the holder shows the minting of coins in the Golden Age. In the coin holder the 2019 gold restrike of the original Ducaton "Silver Rider" was found.
Step 1 - The raw materials
Step 2 - Pouring the clay
The liquid clay is poured into plaster moulds. The porous plaster sucks up the water from the clay, leaving a layer of dry clay on its interior walls. When the clay has reached the right thickness, the liquid surplus is poured off.
Step 3 – Sponging
After some time, the clay is hard enough to be taken out of the mould without being deformed. After air drying, the seams or irregularities have been carefully removed. A secure work that determines the final shape of the coin holder.
Step 4 - Spraying & Firing
The coin holder gets a special layer of liquid clay called ’engobe’ After that the object is put into the kiln to be fired for the first time, at a temperature of 1160°C (2120°F). After 24 hours the body, which is now referred to as 'biscuit', is taken out of the kiln.
Step 5 – Decorating the coin holder
The Delftware painters then paint the Royal Delft decorations on the coin holders by hand. They use brushes made of the hairs of martens and squirrels, and black paint containing cobalt oxide. The cobalt brings about a chemical reaction during the firing process, changing the colour from black to (Delft) blue.
Step 6 - Glazing & Firing
The decorated coin holders are then glazed. The glaze covers the decoration with a non-transparent layer of white. Now the coin holder will be fired in the oven for 24 hours. During the second firing process, which is done at a temperature of 1200 °C (2192 °F), the glaze melts into a translucent layer of glass.
Step 7 – Quality check
The final step of our production process is the quality check. Every piece is inspected from top to bottom to decide it can be put to sale as a “Premium“ Royal Delft product. Royal Delft is the only remaining, original Delftware manufacturer from the 17th century. At the end of the 18thcentury, less attention was paid to Delft Blue, reason for which almost all potteries were forced to close down. When Joost Thooft took over the factory in 1876, he improved the production process in such a way making an even more beautiful and high quality product which brought Delfts Blue into a revival. Up to the present day Royal Delft uses this method of producing which is the worldwide standard of nowadays Delft Blue.