The secret to sparkling transparent blues. Phthalo Blue, PB15 contains several sub-variants, and PB15:3 is one of the most important pigments for artists. Though some may find it overpowering for general use, there is currently no better way to achieve high chroma cyans.

When opaque, Phthalo Blue Green Shade is practically black. With just a little green it makes glacial teals and turquoises. In tints its lilting cyans make stunning sky blues.

This versatile powerhouse blue is a painter’s essential. Phthalo Blues are grouped into Phthalo Blue Red Shade and Phthalo Blue Green Shade, and PB15:3 is the main pigment associated with the Green Shade. It is also known as Phthalocyanine Blue BGS, Phthalo Blue Green Shade or just Phthalo Blue Green Shade.

Some may find the strength of Phthalo Blue overwhelming. We've heard in regard to phthalos in general that the pigment is so strong that the pigment itself is extended. Some brands find a way to tame the phthalo a bit, as Vasari seems to have done here. This is a particularly workable phthalo version.

Like other phthalo blues it is not considered to be toxic, but most painters are not aware that Phthalo pigment may contain toxic contaminants. Specifically, some phthalo pigment can be contaminated by PCBs or dioxins depending on the country and method of manufacture. See Monona Rossol’s work for more.

A particular hazard is presented by older tubes (in some cases as late as 1986) since the manufacture process included the potential for serious toxins. So we steer clear of older phthalos in general. We aren't experts in health and safety though. Monona Rossol's work contains more on this topic.

This variety of phthalo is made from the "b form" of 74160. This makes the best cyans and teals.

Depending on the manufacturer, lightfastness is either excellent or decent in tints.

Recently, Golden Artist Colors (makers of Williamsburg oil paints) undertook some interesting lightfastness research on oil paints regarding how pigments react in various mixing white colors.

Phthalo Blue performed excellently in most mixing whites. However, a notable exception occurred in two of the off-the-beaten-path white colors, which is good to be aware of. One was Flake White (Lead White, PW1 and pure Zinc White, PW4 and in those its lightfastness tanked.

When mixed with standard single-pigment Titanium White, PW6 Phthalo Blue had excellent lightfastness in oils.

Many Phthalo Blue versions will look super-intense in masstone, like this Michael Harding version. However when tinted with white, these colors tend to open up quite similarly to one another. You can find a Phthalo Blue comparison in our article section.