Rublev Colours Dry Pigments - Series 3 Ultramarine Blue (Red Shade) is a classic, high-performance blue pigment with a distinctly warm, red-leaning undertone. Ultramarine Blue (PB 29) is a synthetic inorganic pigment based on the same chemistry found in natural lapis lazuli, formed as a complex double silicate of sodium and aluminium with sulfur compounds. The red shade version is prized for rich, velvety blues, clean violet mixes, and atmospheric darks that feel deeper and warmer than green-leaning blues.

This pigment is rated ASTM Lightfastness I, the highest category, making it a reliable choice for professional paint making and long-lasting artwork. Ultramarine Blue is compatible with other pigments, but it is sensitive to acids, so it should not be used in acidic environments or with acidic mediums and supports.

Ultramarine disperses easily in water-based systems and is widely used for watercolour, gouache, acrylic, and casein paint making. In oil, it has medium oil absorption (38 to 42 g oil per 100 g pigment) and can slow drying slightly. It is also noted as being more difficult to grind in oil than many pigments, but once properly dispersed it produces beautiful colour strength and transparency effects.

Key specs

• Colour Index: PB 29 (77007)

• Pigment type: Synthetic inorganic

• Chemical formula: (Na, Ca)8Al6Si6O24(S, SO4)

• ASTM lightfastness: I (Acrylic, Oil, Watercolour)

• Mean particle size: 1.8 microns

• Oil absorption: 38 to 42 g oil / 100 g pigment

• Density: 2.35 g/cm3

• Series: 3

• Size: 100g

Handling and safety
Not considered toxic in typical use, but as with all dry pigments avoid inhaling dust and avoid ingestion or prolonged skin contact. Conforms to ASTM D-4236.