Benzimidazolone Yellow is a greenish yellow pigment with dull tints and an average drying time. It mixes very cleanly. It mixes cleanly with both Phthalo Green and Titanium White. Although more expensive than many Hansa and Diarylide pigments, its mixing properties, durability, and lightfastness have won it many customers.
Benzimidazolone Yellow has excellent lightfastness and durability. This has made it an extremely important pigment in the printing industry, for applications where lightfastness is a primary consideration. Though it is not absolutely lightfast, it ranks extremely well among organic yellows.
Benzimidazolone Yellow is not considered toxic.
The benzimidazolone group of pigments was developed and patented in 1960 by Hoechst A.G., a German chemical manufacturer that was a forerunner of the pharmaceutical company Aventis.
polychlorinated copper(II) phthalocyanine
C32H3Cl13CuN8 to C32HCl15CuN8 or C32H16CuN8Cl15 (PG7) or C32Br6Cl10CuN8 (PG36)
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.
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.
Phthalo Green has no significant hazards, but it contained PCBs (polychlorinated biphenyls) until 1982.
This bright blue-green was developed in 1935 and has been in use since 1938.