Color Swatch created using heavy application/medium application/50% tint and was applied on acrylic primed canvas (7 oz) material.
This color contains the following pigments:
PB36—Cobalt Chromite Blue Green Spinel
Pigment Type
inorganic
Chemical Name
Oxides of Cobalt and Chromium
Chemical Formula
Co(Al,Cr)2O4
Properties
Cobalt Chromite Blue is an opaque pigment with moderately low tinting strength.
Permanence
Cobalt salts have excellent lightfastness and temperature stability.
Toxicity
Cobalt salts are toxic when ingested or inhaled, and slightly toxic on contact with the skin. Evidence of Chromium(III) carcinogenicity is inconclusive. Chromium(III) salts appear in greenish pigments.
History
n/a
Alternate Names
Cobalt Turquoise, Shepherd Blue
PY40—Cobalt Yellow
Pigment Type
inorganic
Chemical Name
cobalt potassium nitrite
Chemical Formula
K3[Co(NO2)6] • H2O or CoK3N6O12
Properties
Cobalt Yellow is an expensive, transparent, very pure yellow with only fair hiding power. It is reliable in watercolor and makes particularly good tints. However, it must be carefully manufactured in oil form, or it can brown. Cobalt Yellow is known for good mixing quality with all other pigments, and it is useful in glazes and for tinting.
Permanence
Cobalt Yellow has good permanence and lightfastness, and it can withstand strong sunlight.
Toxicity
Cobalt Yellow is highly toxic by inhalation or ingestion. The ingestion of this pigment has caused cyanosis (low oxygen levels in the blood) due to methemoglobinemia.
History
Cobalt comes from the Middle High German word kobolt, an underground goblin, because miners thought cobalt harmed silver ores. The discovery of the potassium and cobalt compound used to make Cobalt Yellow is credited to N.W. Fischer in Breslau in 1848. It was not introduced as an artists’ pigment until 4 years later, by Saint-Evre in Paris. During the previous century, it was considered the only color that could reasonably replace Indian Yellow.
Alternate Names
Aureolin.
