This color contains the following pigments:
Dioxazine Violet is transparent and has very high tinting strength. It is a staining pigment, very dark valued when it is used at full strength. Concentrated, it paints out nearly black, but it mixes with Titanium White to form bright, opaque tints of purple. PV23 produces slightly redder shades than PV37. Because the hue can vary with the conditions of preparation and grinding, it may be offered in red shade, blue shade, and so forth.
Dioxazine Violet has good lightfastness. There may be some concern about it fading or shifting in color in tints and washes. Some artists have reported that PV37, a molecular variant, is more lightfast than PV23.
Two molecular variants of Dioxazine Violet, PV23 and PV37, are available. They have similar properties, but mix slightly differently.
organic, monoazo benzimidazolone
Benzimidazolone Brown is a transparent brown pigment that is heavily staining and dark valued but has moderately low tinting strength. According to its manufacturer Clariant, “It is a dark brown, very transparent benzimidazolone pigment with excellent light, weather, and solvent fastness properties plus high heat stability. Recommended for paste inks, solvent and water based packaging gravure, and flexographic printing inks.” Benzimidazolone Brown has been used in watercolor painting, where transparent brown colors have traditionally been mixed from other pigments.
Benzimidazolone Brown has excellent lightfastness and weather resistance.
Benzimidazolone pigments were developed and patented by Hoechst in 1960, and have gradually come into use as artist pigments.