Holbein Artists' Watercolor Half Pan - Olive Green

Pigment Information

This color contains the following pigments:

PG7-Phthalo Green

PY180-Benzimidazolone Yellow

PR122-Quinacridone Magenta

Pigment Name

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.

Pigment Name

PY180-Benzimidazolone Yellow

Pigment Type

organic, benzimidazolone

Properties

Benzimidazolone Yellow 180 is a transparent greenish yellow pigment with high tinting strength. It is very similar in hue to PY74, a Hansa Yellow pigment with even higher tinting strength that was the traditional yellow used in CMYK (four color) process printing.

Permanence

Pure tones of Benzimidazolone Yellow 180 have excellent lightfastness. Tints with white are considered less lightfast. Benzimidazolone Yellow 180 is considered to have greater lightfastness than PY74, which it often replaces in printing technology.

Toxicity

Benzimidazolone Yellow 180 is not considered toxic.

History

Benzimidazolone pigments were developed by Hoechst in the 1950s and 1960s. Benzimidazolone Yellow 180 is used in printing and plastics. Although it is more expensive than PY74, a Hansa Yellow, and has lower tinting strength, its lightfastness often makes it the yellow of choice in four color process printing.

Pigment Name

PR122-Quinacridone Magenta

Pigment Type

organic, quinacridone

Chemical Formula

C22H16N2O2

Properties

Quinacridone Magenta is a semi-transparent and powerful bluish red with an impressive mixing range. It makes an excellent glazing color and is one of the bluest of the Quinacridone colors. The pigment's properties vary considerably, depending on how it is ground. Quinacridone pigments have relatively low tinting strength in general. For this reason, quinacridone colors are often expensive, because more pigment is required in the formulation.

Permanence

Quinacridone Magenta offers very good lightfastness in most media, but some have argued that it is less lightfast in watercolor form. Although Quinacridone Magenta received only a passing grade of "fair" under ASTM test protocols, other test results have rated the pigment very good to excellent. Transparent reddish violet pigments in general have more problems with lightfastness than any other range of colors. PR122 is often used as the Magenta of CMYK (four color) process printing because it offers a better tradeoff between tinting strength and lightfastness than other pigments in its class.

Toxicity

Quinacridone Magenta has no acute hazards. Overexposure to quinacridone pigments may cause skin irritation. Quinicridone pigments contain a compound found to be a skin, eye, and respiratory irritant.

History

Quinacridone Magenta came from a red violet aniline dye that was first produced in 1858 by Natanson. It was called Magenta to commemorate a battle in Magenta, Italy. Over time, Magenta became the standard color name for a deep, violet red. Although quinacridone compounds became known in the late 19th century, methods of manufacturing so as to make them practical for use as commercial pigments did not begin until the 1950s. PR122 has become particularly popular in the formulation of Magenta for CMYK process printing.