An essential color to the advanced artist’s paintbox, genuine Cerulean Blue is far easier to handle in mixes for naturalistic work, such as foliage, botanicals and landscape, and even in portraiture. This color is much more earthy than phthalo blue, PB15, and it is an indispensable blue when opacity is needed in the blue-greens. It is still a bright blue, but it will mix differently into a palette than phthalo.

As a pigment it's opaque or semi-opaque, but it is sometimes diluted, probably due to its expense. It requires a high amount of oil to make it into a paint, and tends to be a slower drying oil paint. Cerulean tends to be greener than Cobalt Blue, PB28.

Cerulean Blue is made of Cobalt Stannate, which is sometimes listed as Cobalt tin oxide or Oxides of Cobalt and Tin on the paint label.

PB35 is usually thought of as somewhere in the B class for toxicity, so cerulean does require careful handling and the precautions fitting for the category. It contains cobalt, so please see the Artist's Guide to Health and Safety for information about the hazards associated with cobalt pigments. The author's most recently updated writing can be found through her site.

It has excellent lightfastness, and under normal sunlight conditions this gets solid excellent marks. However in the recent lightfastness testing done by Golden there were some unexpected results when exposed to a special form of artificial testing light. However this is generally considered a lightfast pigment regarding natural light.

It tends to be a very stable pigment with a reputation for lightfastness.

Cerulean Blue pigment in oil tends to have a natural heft to it, and this is a characteristic of the pigment itself.