Cobalt Green Dark Pigment
Rublev Colours Cobalt Green Dark pigment is a green cobalt zinc oxide, semi-transparent of limited hiding power discovered by Rinmann in 1780. Due to its permanence, it can be used in all painting techniques. The poor tinting strength and high cost of cobalt green kept it in limited use. Learn more about Cobalt Green Dark.
Rublev Colours Cobalt Green Dark pigment is a green cobalt zinc oxide, semi-transparent of limited hiding power discovered by Rinmann in 1780. Due to its permanence, it can be used in all painting techniques. The poor tinting strength and high cost of cobalt green kept it in limited use. Field called it, “chemically good and artistically bad.”
|Common Name||Mineral Name||Chemical Name||Source/Origin|
|Cobalt green||None||Cobalt Zinc Oxide||United Kingdom|
|Common Names:||English: cobalt green, Rinmann's Green
French: vert de cobalt
German: Cobaltzinkoxidgrün, Rinmansgrün
Italian: verde cobalto, verde di zinco
|Synonyms:||Cobalt Green Pale
C.I. Pigment Green 19
Cobalt Green Bluish
Cobalt Green Deep
Cobalt Green Light
Cobalt Green Pale
Cobalt Green Pure
Cobalt Green Turquoise
Cobalt Green Turquoise Light
Cobalt Turquoise Deep
Cobalt Zinc Oxide
Pigment Green 19
|Colour Index:||Pigment Green 19 (77335)|
|Chemical Name:||Cobalt Zinc Oxide (Cobalt(II)-oxide-zinc(II)-oxide)|
|ASTM Lightfastness Rating|
|Oil Absorption:||34–37 grams oil / 100 grams pigment|
|Health and Safety:||
Skin contact may cause allergies, especially on elbows, neck, and ankles. Chronic inhalation may cause asthma. Ingestion may cause vomiting, diarrhea, and the sensation of hotness. May contain trace amounts of soluble cobalt, but should not be a hazard in normal artist use. Avoid dust, avoid spraying, don't use your mouth to point your brushes. Conforms to ASTM D 4326.
WARNING: Exercise care when using dry pigments. Do not eat, drink or smoke. Avoid breathing dust. Use a NIOSH-certified dust respirator. Wash hands immediately after use. If the creation of dust is likely, wear protective clothing.
History and Origin
The preparation of zinc oxide at the end of the eighteenth century made the development of cobalt green, also known as zinc green, possible. The Swedish chemist, Rinmann is credited with developing a process for making a compound of cobalt and zinc in 1780 that he published with the Stockholm Academy of Sciences. Arthur Herbert Church published Rinmann's process in his book, The Chemistry of Paints and Painting. According to Church, cobalt green was made with the compounds of oxides of zinc and cobalt by mixing them "with an alkaline carbonate" and then exposing the mixture to strong heat. After washing the sediment that resulted, the pigment was ready to grind. The pigment was always bluish-green in spite of the ability to widely vary the proportion of zinc to cobalt oxides in production. The compound that is formed is chemically joined.
Cobalt Green is a synthetic inorganic pigment composed of an isomorphous mixture of cobalt zincate and zinc oxide heated at high temperatures which cannot be chemically separated. Paler tints require greater amounts of zinc oxide.
How cobalt green is made can be seen from webexhibits.org.
Permanence and Compatibility
Cobalt Green is considered permanent in all painting techniques.
Oil Absorption and Grinding
Cobalt Green absorbs a moderate amount of oil (34 to 37 grams per 100 grams of pigment), which slows the drying of oil paint and yet is a moderately fast-drying oil color. It disperses well in both oil- and water-based paints and is easy to mull by hand to a smooth paste.
Cobalt Green is not considered toxic, but care should be used in handling the dry powder pigment to avoid inhaling respirable dust particles. May contain trace amounts of soluble cobalt, but should not be a hazard in normal artist use. Avoid dust, avoid spraying, don't use your mouth to point your brushes.
Very toxic to aquatic life with long-lasting effects.
|Processing Time||Usually ships the next business day.|