D102 Horizon Blue/Bleu d'Horizon - PG7 Phthalo Green (Organic, Polychlorinated copper(II) phthalocyanine), PB15 Phthalo Blue (organic copper Phthalocyanine), Titanium White PW6 (inorganic, Titanium dioxide).

Series: A

Lightfast: ***

Pigment 1: PG7 Phthalo Green

This bright blue-green was developed in 1935 and has been in use since 1938.

Pigment name: PG7 Phthalo Green

Pigment Type: Organic

Chemical Name: Polychlorinated copper (II) phthalocyanine

Properties: Phthalo Green is a transparent, cool, bright, high-intensity colour 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 excellent base colour for mixing a range of bright greens. Phthalo Green is considered a perfect alternative to Viridian because it is intense and mixes well, and can emphasize mineral colours in various tints. However, its tinting strength is very high so that it can overpower other colours. 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.

Alternate Names: Bocour Green, Cyan Green, Intense Green, Monastral Green, Phthalocyanine Green, Rembrandt Green, Thalo Green, Winsor Green.

Pigment 2: PB15 Phthalo Blue

Developed by chemists using the trade name Monastral Blue, the organic blue dyestuff is now known as Phthalo Blue, was presented as a pigment in November 1935 in London. Its discovery was accidental. The dark colour 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 cyan to replace Prussian Blue.

Pigments Name: PB15 Phthalo Blue,

Pigment Type: organic

Chemical Name: copper phthalocyanine

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 colour strength can be controlled, they make predictable mixed colours. In oil form, blues are intense and slow drying. When mixed with other colours 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 colours with mineral colours and is considered more reliable than Prussian Blue while sharing the same physical and colour properties. Phthalo Blue is a good colour 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).

Alternate Names: Bocour Blue, Cyan Blue, Helio Blue, Heliogen Blue, Intense Blue, Monastral Blue, Phthalocyanine Blue, Rembrandt Blue, Thalo Blue, Winsor Blue.

Pigment 3: Titanium White PW6

Titanium is the ninth most abundant element in the Earth's crust; however, mineral deposits that are economical to mine are less common. Titanium dioxide was first discovered in 1821, although it could not be mass-produced until 1919. Widespread use of the pigment began in the 1940s. Since that time, it has become the most commonly used white pigment. The name comes from the Latin word Titan, the name for the elder brother of Kronos and ancestor of the Titans, and the Greek word tito, meaning day or sun.

Pigment Name: Titanium White PW6

Pigment Type: inorganic

Chemical Name: Titanium dioxide

Properties: Titanium White is the most brilliant of the white pigments. It is considered an all-purpose oil colour useful in all techniques and the best all-around white. Its masstone is neither warm nor cool, placing it somewhere between Lead White and Zinc White. It is less prone to cracking and yellowing than Lead White, but it still yellows easily. Titanium White dries slowly in oil form, more slowly than Lead White but more quickly than Zinc White. It is opaque in oil and acrylic forms and semi-opaque in watercolour. This pigment has good chemical stability, and its tinting strength is superior to both Lead White and Zinc White.

Permanence: Titanium White has excellent permanence and lightfastness.

Toxicity: Titanium dioxide is highly stable and is regarded as completely non-toxic. Animal studies do not indicate that it is absorbed biologically, even after long periods of exposure. The primary safety concern is with inhalation of fine pigment dust particles. If inhaled in large amounts over the course of several years, Titanium White may cause a benign pneumoconiosis that is visible on x-rays. The National Institute of Occupational Safety and Health (NIOSH) considers fine titanium dioxide particles, if inhaled, to be a human carcinogen. The primary concern for artists is to avoid exposure to fine particulate dust from raw pigments.

Alternate Names: None.