Royal Delft Blue and Colored Decorative Earthenware of the Royal Porcelain Bottle Anno 1653

For the manufacturing of Delft pottery the clay ingredients are carefully selected. In 1653 at the start of the Royal Delft Porcelain Bottle, yellow-baking clay was used, which after having been baked, was first covered with tin-glaze and then were painted with crushed oxides.
During the second baking in the oven came the color.
A century later, they moved on to white-baking clay, like the English example of Wedgwood.
This gave the opportunity to paint directly after the first baking and then immersing it in enamel for the second bake.
The photo shows the right vase is painted with cobalt and that still looks black-gray. After the glaze is applied in unfired state it is opaque as you can see on the left vase. Now the products go into the oven for the second time to come out to like the blue cup in the middle of the picture.
A surprisingly beautiful process.

You can recognize the original Delft decorative pottery by its logo that is ingrained on each article.
Delft Blue Earthenware
Delft Pynacker Earthenware