Phthalo Blue Royale

Phthalo pigments are a family of blue and green synthetic organic pigments based on variants of copper phthalocyanine, a deep blue compound produced by the reaction of phthalic anhydride, urea, copper and ammonia. It was first sold as a pigment in 1935 under the trade name Monastral Blue (some paint manufacturers still use this name). When it was discovered, it was thought to be the most significant advance in artist pigments since the discovery of synthetic Ultramarine Blue in 1826.