Art Spectrum Artists' Soft Pastel - Green Gray 574T

Pigment Information

This color contains the following pigments:

PG17-Chromium Oxide Green

PBk9-Ivory Black

Pigment Name

PG17-Chromium Oxide Green

Pigment Type

inorganic

Chemical Name

chromium oxide

Chemical Formula

Cr2O3

Properties

Chromium Oxide Green is a dull, dense, willow or pale green color that is completely opaque. It has an average drying time and a low tinting strength. It is fairly flexible in oil form and is suitable for all purposes and mediums. This pigment is less versatile in mixtures than Viridian and Phthalocyanine Green, but mixes well with other colors without overpowering them.

Permanence

Chromium Oxide Green has excellent permanence, even at high temperatures.

Toxicity

Chromium Oxide Green is slightly toxic. Evidence of Chromium(III) carcinogenicity is inconclusive. Chromium(III) salts appear in greenish pigments such as PG17. Chromium(VI) salts, which appear in yellowish pigments, have been proven to cause cancer.&nbsp

History

Louis-Nicolas Vauquelin discovered the element chromium in lead chromate in 1797. It began to be used as an enamel and ceramic color in 1809, but it had limited use as a pigment until 1862, because of its cost. It is the most commonly used green for military camouflage because it appears the same shade as living foliage under infrared light.

Pigment Name

PBk9-Ivory Black

Pigment Type

charred animal bone

Chemical Name

carbon + calcium phosphate

Chemical Formula

C + Ca3(PO4)2 or C x CaPO4

Properties

Ivory Black is a cool, semi-transparent blue-black with a slight brownish undertone and average tinting strength. It mixes well with any color, and creates a range of dull greens when mixed with yellow. It has good properties for use in oil, can be slow to dry in oil form, and should never be used in underpainting or frescoing. Ivory Black is denser than Lamp Black.

Permanence

Ivory Black is very lightfast and has good permanence, though it is considered the least permanent of the major black pigments.

Toxicity

Ivory Black has no significant hazards.

History

Ivory Black is a carbon based black first named as Elephantium, and described in the 4th century BCE as produced by heating ivory scraps in clay pots to reduce the ivory or bone to charcoal. The deviation in names is because the more expensive varieties of this pigment were made by burning ivory, and the less expensive ones by burning animal bone. In the 19th century, the name Ivory Black was finally permitted to be applied to Carbon Black pigments made from bone. True Ivory Black is rare in modern times due to the protection of ivory, and the synthetic variety produced today was discovered in 1929. Bone Black is produced as an industrial pigment.