Sennelier Watercolour S1 Phthalo Blue (326)

Phthalo Blue PB15:3 is a structural variant of Phthalo Blue PB15 that produces more greenish tones. Chemical Name: beta copper phthalocyanine

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 a cyan to replace Prussian Blue.

Alternate Names: Phthalo Blue Green Shade, Winsor Blue Green Shade