Oxides as Stains and Majolica Colors Use Sheet

Ceramic Coloring "Oxides" ^[1] are very useful as additions to your glaze repertoire. Each of these oxides has different characteristics and uses. Most will stain clothing. They are all used in relatively thin coats from very translucent coats to coats that just begin to become opaque. Most are expensive and should be treated with respect. Some oxides like iron are very versatile, able to be used under, over and in glazes or by themselves. Others are less so. Some cause crawling or will not stick by themselves. Each has its own properties. Oxide surfaces are not usually durable and should not be used as food surfaces

Contact with the ceramic "oxides" with the exception of Iron Oxide, Titanium Dioxide Rutile, and Ultrox should be avoided. If you get any of these materials on your skin or clothing you should wash them off carefully before leaving the studio. Use gloves.

1. Iron Oxide. The most versatile and forgiving. It can be used under glazes , over glazes or without glaze. It is often brushed into texture and then washed off with a sponge. Can cause running. It is particularly nice over or under Shino glazes on light clay bodies. It reacts with celadon glazes to make them darker greens or kakis or tenmokus.
   Very thick, or by itself it should not be considered a food surface. Consult instructor on food surfaces
2. Manganese Dioxide. Nearly as forgiving as Iron Oxide, it should be used in thinner coatings. It tends towards browns grays and blacks when thicker and tans and creams when thinner. Use gloves. Very thick, or by itself it should not be considered a food surface. Consult instructor on food surfaces
3. Rutile. Will cause crawling under glazes unless applied very translucently. It gives nice textures over glazes when applied just translucent or thinner. It gives yellows but can be too dry a surface if applied thickly. It works on unglazed clay only in the soda kiln.
4. Copper Carbonate. This material is poisonous and should not be used on food surfaces without consulting your instructor. It is a forgiving material but can be applied too thick. When applied thinly it can go under a glaze. Tends towards pitted blacks when on thick. Can be applied over a glaze works well on Shino, Bauer Clear, and Vivika's. Cannot be used to cover large areas, it will fume. A common technique is to use it thickly in texture and then apply a thin slip or sigelllata over it. The copper will melt through the sigellata and cause a black stain. Copper Carbonate must be kept from the sinks. If you are going to use it and wash it off, ask first so we can do it properly. Use Gloves.
5. Cobalt Carbonate . It is blended with Alberta slip to give us a mixture that is not as harsh and will not spit off the pots unless thick. This material should not be used on food surfaces without consulting your instructor. Can be used over and under glazes. Under glazes it may cause crawling if too thick. Not effective without glaze, it comes out a dull black. It may not be used by itself and the inside of vessel. Cannot be used to cover large areas, it will fume. It is very expensive and should not be wasted. Use Gloves.
6. Chrome Oxide. Greens under almost all circumstances. Use sparingly and thin. Not on food surfaces. Use gloves. Use sparingly, it fumes. If the technique you are using requires it to be washed off the pot please ask first so we can do this properly and keep chrome out of the sink.
7. Black Mason # 6600 Stain. Use translucent over glaze.This material should not be used on food surfaces without consulting your instructor. . Use gloves. It may work under glazes as well.
8. Mason 6020 Pink Stain. Must be used thin. Do not use on food surfaces. Use gloves. It can fire very dry if thick.

[1] The carbonates become oxides when fired.