Royal Talens Gouache - Turquoise Blue, 20 ml tube

This color contains the following pigments:

PB15-Phthalo Blue

PG7-Phthalo Green

PW5-Lithopone

Pigment Name

PB15-Phthalo Blue

Pigment Type

organic

Chemical Name

copper phthalocyanine

Chemical Formula

C32H16CuN8

Properties

Phthalo Blues are pure and clean primary blues with superior covering power. They have a very high tinting strength and tend to overwhelm other pigments, but if color strength can be controlled, they make predictable mixed colors. In oil form, blues are very deep and slow drying. When mixed with other colors or if chlorine is added, Phthalo Blue quickly tends towards green. When using alone, mix with some white, as Phthalo Blue can be semi-transparent and almost black on its own. It is among the most compatible of modern colors with mineral colors and is considered more reliable than Prussian Blue, while sharing the same physical and color properties. Phthalo Blue is a good color for glazing.

Permanence

Phthalo Blues are completely lightfast and stable and are permanent for all paint uses. 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 Blues have no significant hazards, although those made before 1982 contained some PCBs (polychlorinated biphenyls).

History

Developed by chemists using the trade name Monastral Blue, the organic blue dyestuff now known as Phthalo Blue was presented as a pigment in November 1935 in London. Its discovery was accidental. The dark color was observed in a kettle where a dye was being made from a British dyestuff plant. The demand for such a pigment came from commercial printers who wanted a cyan to replace Prussian Blue.

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

PW5-Lithopone

Pigment Type

inorganic

Chemical Name

coprecipitated zinc sulphide and barium sulphate

Chemical Formula

Zn + BaSO4

Properties

Lithopone is a low tinting strength, semi-transparent white pigment that is often used as a filler or extender in other colors, or as the base for laked pigments.

Permanence

Lithopone is absolutely permanent and lightfast.

Toxicity

Lithopone is not toxic.

History

Lithopone was discovered by G.F. de Doubet in 1850. It  was developed commercially in the 1870s as a substitute or supplement for lead carbonate, to overcome the many shortcomings of white lead pigment, including toxicity, poor weathering, and darkening in the presence of sulfur compounds. It is used most often in interior paints and enamels. Its use as a white pigment has been superceeded in many applications by titanium dioxide.