Phthalo Blue is the short name for Phthalocyanine. It is an unusual case of the scientific name for a pigment gaining common usage and accepted by the public. The “Ph” at the beginning can look confusing to those new to the color, but it is silent so that the name is pronounced as “thalo”. When first launched in 1936 it had another name – it was called Monastral Blue and a few paint company’s still call it that but most ended up reverting to the chemical name.
Chemical Description: Copper phthalocyanine
Pigment Number: PB15.3
Lightfastness Rating: ASTM I
Pigment Opacity: Transparent
Paint Opacity: Transparent