Color Swatch created using heavy to light application and was applied on 100 lb (163 gsm) drawing paper material.
This color contains the following pigments:
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.
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.
Alternate Names
Chrome Oxide Green, Olive Green, Permanent Green. Varieties of Chromium Oxide Green include Arnaudon's Green, Dingler's Green, Plessy's Green, and Schnitzer's Green.
PBk9—Ivory Black
Pigment Type
charred animal bone
Chemical Name
carbon + calcium phosphate
Chemical Formula
C + Ca3(PO4)2 or C × 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.
Alternate Names
Animal Black, Blue Black, Bone Black. Paris Black is an inferior grade of Ivory Black. Incorrectly labeled as Frankfort Black.
PG7—Phthalo Green
Pigment Type
organic
Chemical Name
polychlorinated copper(II) phthalocyanine
Chemical Formula
C32H3Cl13CuN8 to C32HCl15CuN8 or C32H16CuN8Cl15 (PG7) or C32Br6Cl10CuN8 (PG36)
Properties
Phthalo Green is a transparent, cool, bright, high intensity color used in oil and acrylics. It comes from a Phthalocyanine Blue pigment where most of the hydrogen atoms have been replaced with chlorine, forming highly stable molecules. It has similar pigment properties and permanence to Phthalo Blue. It is slow drying and an excellent base color for mixing a range of bright greens. Phthalo Green is considered a very good alternative to Viridian because it is intense and mixes well and can be used to emphasize mineral colors in various tints. However, its tinting strength is very high, so it can overpower other colors. This pigment most closely resembles the discontinued and toxic Verdigris.
Permanence
Phthalo Greens are completely lightfast and resistant to alkali, acids, solvents, heat, and ultraviolet radiation. They are currently used in inks, coatings, and many plastics due to their stability and are considered a standard pigment in printing ink and the packaging industry.
Toxicity
Phthalo Green has no significant hazards, but it contained PCBs (polychlorinated biphenyls) until 1982.
History
This bright blue-green was developed in 1935 and has been in use since 1938.
Alternate Names
Bocour Green, Cyan Green, Intense Green, Monastral Green, Phthalocyanine Green, Rembrandt Green, Thalo Green, Winsor Green.
