Gamblin 1980 Oils - PB15:2-Phthalo Blue (alpha copper phthalocyanine); PY83 Indian Yellow; HR70andnbsp;Diarylide Yellow

Sap Green: Originally made from berries, this actual lightfast colour is a predictable mixture that can be easily warmed with Hansa Yellows or cooled with blues.

Pigmentandnbsp;Composition and Permanence:andnbsp;

Pigment Name: PB15: 1-Phthalo Blue

Pigment Type: Organic

Properties

Phthalo Blue PB15:1 is a structural variant of Phthalo Blue PB15 that produces more reddish tones.

Permanence

Phthalo Blues are completely lightfast, stable, and permanent for all paint uses. Due to their stability, they are currently used in inks, coatings, and many plastics 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 colour was observed in a kettle where a dye was made from a British dyestuff plant. The demand for such a pigment came from commercial printers who wanted cyan to replace Prussian Blue.

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Pigment Name: PY83 Indian Yellow Diarylide Yellow 83; HR70

Pigment Type: organic, disazo

Properties

Diarylide Yellow is a semi-opaque, moderately staining, intense deep reddish yellow pigment with good tinting strength.

Permanence

Diarylide Yellow 83 has excellent lightfastness and permanence. However, it can fade in tints, so some artists do not consider it suitable as an artist’s colour. Many other diarylide yellow pigments are reported to have fair to poor lightfastness, and some are entirely fugitive.

Diarylide Yellow 83 is one of the most permanent of the entire group.

Toxicity

Diarylide Yellow has no significant acute hazards, but chronic hazards have not been well studied.

History

Diarylide Yellow comes from a family of azo pigments called Diarylide. These yellow-hued pigments were developed around 1940 and are very important in printing inks.

Indian Yellow: This colour has been prized for hundreds of years. But only now has the colour been made with a completely lightfast pigment.