E130-E139 Blue and purple

Indanthrone blue, also called indanthrene, is an organic compound with the formula (C14H6O2NH)2.

It is a dark blue solid that is a common dye as well as a precursor to other dyes.

ndanthrone is utilized as a blue pigment (C.I. Pigment Blue 60), primarily in the process of vat dyeing, often referred to as C.I. Vat Blue 4.

Indanthrone is a vat dye, synthesized to provide highest color fastness for the dyeing and printing of predominantly cellulose-based textile fibers.

Fabrics dyed with indanthrene fulfill the highest standards and exhibit exceptional wash fastness, boil fastness, light fastness, weather fastness and chlorine fastness.

It is a pigment that can be used in the following media: acrylic, alkyd, casein, encaustic, fresco, gouache, linseed oil, tempera, pastel, and watercolor painting.

It is used to dye unmordanted cotton and as a pigment in quality paints and enamels.

As a food dye, it has number 130, but it is not approved for use in either the United States or the European Union.

It has excellent light fastness, but may bleed in some organic solvents.

Indanthrone blue was the first example of the brand "Indanthren" (an acronym for Indigo from anthracene) introduced by BASF in 1901.

One result is that even now, in Japan vat dyes are commonly described as threne dyes, derived from the Japanese transliteration of the brand.