When fired in oxidation, a small amount of iron oxide (1–5%) gives a honey- or amber-yellow color. Iron oxide in a barium glaze that is high in zirconium will also give a yellow color in reduction. Iron oxide was used in low-fired yellow porcelain glazes in Imperial China, and also in lead slipware glazes in 17th-century England and France. Lead antimonate was used to give a bright yellow on low-temperature majolica ware made in Renaissance Italy. Vanadium and tin oxide are also used to make a yellow stain that can be used at higher temperatures than antimony, but which does not give such a bright yellow.
Uranium oxide was used as a high-temperature yellow colorant in the early 20th century, but it is now unavailable owing to its radioactivity. Cerium and titanium give a creamy yellow, as does rutile. A small amount of nickel (1–3%) along with titanium (10%) can produce a mustard yellow.
To obtain bright yellows, it’s necessary to use a commercial stain. Praseodymium oxide and zirconium silicate are often used to make yellow stains, although they’re not as strong as cadmium-sulphide yellows, which are bright orange-yellow. Zinc sulphide is added to cadmium sulphide to make light primrose-yellow stains.
Excerpted from Colour in Glazes by Linda Bloomfield, available on the Ceramic Arts Daily Shop.