Matisse Indigo is pure PB60 which is commonly called Indanthrone Blue which is a little confusing because the pigment is actually described as an anthraquinone. It is a vat pigment of very great lightfastness and has a reputation for being one of the most permanent organic pigments available. Even in very light tints it should not fade. In many ways it is a good cousin to Phthalo Blue for while they are not related chemically both have the very dark color that artists need when painting but while Phthalo Blue is a greenish blue and is therefore cool, Matisse Indigo is a reddish Blue and therefore a warm blue. This means that for the first time in history artists have both warm and cool versions of a very deep dark blue of great lightfastness.
Chemical Description: Indanthrone
Pigment Numbers: PB60
Lightfastness Rating: ASTM I
Pigment Opacity: Transparent
Paint Opacity: Semi-Transparent