Rublev Colours Luberon Raw Sienna is a warm, translucent iron oxide earth pigment from the Luberon Massif in Provence, southern France. Sienna is closely related to yellow ochre, but it is typically warmer and more transparent, making it ideal for glazing, luminous underpainting, and natural skin and landscape mixtures. This Luberon Raw Sienna is darker and warmer than Luberon Raw Sienna Light, with a rich yellow-brown character and a gentle red-brown presence in the mass tone.

Natural sienna earth is coloured primarily by iron oxide hydroxide (goethite, α-FeOOH), modified by the natural mineral balance in the deposit, including varying proportions of clay, silica, limestone, and trace manganese compounds. These natural variations are what give genuine earth pigments their depth and subtlety. In practice, Raw Sienna excels for warm underlayers, transparent golden veils, and mixing clean, believable neutrals without chalkiness.

Luberon Raw Sienna is considered permanent and is compatible across common binders, including oil, tempera, fresco, and water-based paints. It has excellent transparency and a medium tinting presence in mixtures, making it a dependable studio earth for both traditional and contemporary palettes.

Key specs

• Colour Index: PR 102 (77492)

• Pigment type: Natural inorganic (iron oxide hydroxide earth)

• Chemical formula: α-FeOOH

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

• Oil absorption: 45 to 55 g linseed oil / 100 g pigment

• Density: 3.3 to 4.3

• Hardness: 5.0 to 5.5

• Size: 100g

Handling and safety
Considered non-toxic, but as with all dry pigments avoid inhaling dust and avoid ingestion or prolonged skin contact. Use good ventilation and a dust mask when handling powder.