Ceramic stains are mixed metal oxide pigments that crystallize in stable oxide lattices and the color is due to the incorporation of colored cations in the lattice.
The crystal lattice of each prepared ceramic stain has different crystallographic structure such as spinel, garnet, zircon, corundum, etc. The properties are quite different from each other but it is possible to prepare similar colors in different structural systems. For example pink color can be prepared in different crystal lattices such as chrome-tin pink, chrome-alumina pink and manganese-alumina pink. While chrome-alumina pink spinels require the absence of calcium oxide but a surplus of zinc oxide and alumina in the coating, chome-tin pink requires a lot of calcium oxide but no zinc oxide. Various factors like the base glaze chemistry, color shade, temperature, and end use determine the system you should choose.
Thus, stains do not come with an unconditional color guarantee. The shade produced depends on many of factors including the host glaze chemistry, on/over/underglaze use, glaze thickness, amount of opacifier, firing temperature, etc. Certain systems are quite flexible and produce color in many kinds of glazes (ie. cobalt silicate). Other systems either require that certain oxides be present in the host glaze in minimum amounts or others not be present at all. For example, chrome-tin pink stains will not develop color if zinc is present or if there is inadequate calcia. It is common to hear people say that their pink stain ´burned out´, but generally the stain is being used in an incompatible glaze base. Inadequate firing or reducing furnace atmosphere may also cause this trouble.

Among the inorganic pigments, cadmium pigments have particularly brilliant red and yellow colors as well as high covering power. However, these pigments which crystallize with hexagonal wurtzite lattice are not stable at high temperatures and cannot be used in ceramic glazes or as underglaze pigments.

Many stains are almost standard and the system of their composition is well known across the industry. For example, a green stain might contain chrome, cobalt and silica and be labeled ´CrCoSi´. Although silica is not a colorant itself, it is included to create a stable silicate crystal structure with the other two.
The system, the maximum firing temperature, the required glaze properties for optimum results and the Pantone color references for each color are given below.


Glaze colors are light fast and temperature resistant. Depending on the structural system most of them can reliably be used over 1000°C.
Glaze colors can be used for coloring ceramic glazes, enamel slips, engobes and glass mosaic, directly by mixing and dispersing the paint into the coating. They can also be used as underglaze colors for decorating ceramics and tiles simply by mixing the paint with finely ground bisquit, glaze and kaolin in proper amounts and adding a suitable medium to permit the application.
We offer cadmium group pigments only for coloring porcelain enamel. Similar color tints have specially been produced for glass mosaic. They have different product codes and formulation. They all should be used in clean and white glass powder.