This isn't the genuine indigo which can be seen here however it is an excellent approximation made from modern lightfast pigments. Consisting of Phthalo Blue, Quinacridone Violet and Carbon Black.
"My deep, rich Indigo is both organic and inorganic: it is transparent, has an average drying time along with excellent lightfastness and high tint power.
An outcry from artists for Indigo has been amassing for years. Finding and securing an Indigo pigment that meets my high standards is essential to me before I consider making an oil paint colour. After careful testing of various Indigo pigments to find which one can meet my colour standard, I have finally found one that I like.
Nocturne painters will be especially pleased as my new Indigo is what you have been waiting for! Artists who like painting anything from, sultry skies to more conservative painters looking for ways to enhance greys and shadows, my Indigo is a paint you should explore. My very rich, deep, dark Indigo has an uncompromising quality and consistency along with all the hallmark characteristics of a Michael Harding product. It is truly delicious, beautiful, and inky."
Pigments - PBk 6, PB 15.3, Pv 19
Vehicle - Linseed Oil
Opacity - Semi-Transparent