PG36—Phthalo Green

Pigment Type

organic

Chemical Name

polybromopolychlorinated 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.  Pigment PG36 differs from PG7 in that a portion of the chlorine atoms are replaced with bromine atoms, which are reactively similar, but cause a yellow shift that is especially noticeable in mixtures. Phthalo Green 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.