Do you know why enamels look “opaque” before being put in the oven?

In the world of ceramics, there are two ways to give color to a piece; the first is cold painting, which is done with acrylic paints and is commonly used in craft classes. It is called “cold” because the paint is left to dry and does not have to be baked, however, it only works for decoration, it cannot be used for food consumption. The colors you see on the container are the same when you apply them.

Photo: Pinterest

Then there is the ceramic to which the glaze or enamel is applied. This is made of various pulverized minerals, previously weighed because they are formulated, and water is added to make it liquid and thus be able to adhere to the ceramic piece. It needs to go back into the oven so that the powder melts and thus becomes the coating of the piece.

Photo: Escamol Studio

Pieces that are for consumption, such as cups and shots, must be glazed in this way for different reasons: to ensure they are food grade and to avoid toxic elements, and also to prevent them from becoming porous and allowing water to permeate.

Glazing is only half of the process of manufacturing a ceramic piece. The challenge is to do colour tests with the formulated glazes beforehand, to see the colour that the formula gives us.

Ceramic colors will always look like chalk before being put into the oven, they have an earthy color, and only when they go through the fire will the color be revealed, that is why it is important to apply previously tested glazes to know what color we are applying. There are two ways to color a piece: with pigments; which will give us the intensity according to the saturation, if it is matte or shiny. And the coloring oxides, such as cobalt, iron and copper (to mention a few) which are a surprise since the color they give us depends a lot on the formula, I repeat: that is why it is important to make glaze samples, since in ceramics the colors do not work with the Pantone code as in those printed on paper or fabric, here we are working directly with elements of the periodic table and you could say that creating glazes is a mini laboratory.

Raw enamel Photo: Escamol Estudio

Baked enamel Photo: Escamol Estudio

For these reasons, if a person wants the same color or finish as they saw on Pinterest or another existing piece, the supplier has to do tests to create something similar, which is not easy, since many factors influence it: if the piece was made at high or low temperature, the type of oven, if they are commercial enamels or made from scratch, if they are industrialized, even the country of origin. Even if previously tested commercial enamels are used, factors such as the application and the type of oven influence it.

Now that you know everything that is behind the color of a ceramic piece, I recommend that you ask your advisor or supplier what colors they have in their line when you order your pieces, and that will help reduce costs and times of your project.

Same piece, different enamels Photo: Escamol Estudio