Rare but sometimes found in artist paints. General information can be found in the entry for PB15 as well as the in-depth article on Phthalo blues. This is the "e form" of pigment 74160.
In terms of health and safety, these pigments contain copper. Please see the Artist's Guide to Health and Safety for information about the hazards associated with copper pigments. The author's most recent updated writing can be found through her site. See also the note at the bottom of this section on dioxins and PCBs.
Phthalo Blue requires a moderate amount of oil. Opinion is divided on its drying time with some saying medium to slow and others listing it as fast. It seems to frequently contain additives, stabilizers, and extenders. This may have less lightfastness (ASTM II) in watercolors. While phthalos are thought to be less toxic than other some paints, avoid tubes made before 1982 (or even we have heard as late as 1986) as they may be contaminated with impurities such as PCBs. Handle all artist colors with care.
