R&F Pigment Stick - Blue Ochre, 38 ml
This colour's top tone and undertone have a similar edginess as our Indigo, but this different mix is much greener but still very blue. Rubbing it out reveals a surprising yellowish brown—a Cobalt blue and Raw Sienna blend.
- Pigment Composition: PB28-Cobalt Blue; PBr7-Raw Sienna
- Dimension: 38 ml. stick measuring 5" x 3/4" diameter
- Paint Lines: Encaustic, Pigment Stick
- Opacity: Transparent
- Pigment Stick Drying Rate: Medium
- Classification: Mixed
- Chemical Composition: Cobalt Blue + Raw Sienna
- Safety Information: Conforms to ASTM D-4236
Pigment Name: PB28 Cobalt Blue
Classification: Inorganic
Chemical Composition: Cobalt (II) oxide + aluminum oxide
Properties
Cobalt blue is a semi-transparent pigment with low to moderate tinting strength. When it dries, it appears lighter and less saturated. Pigment particles are large and grainy. Differences in how the pigment is ground and mixed lead to considerable differences in its performance among various manufacturers.
Permanence
Cobalt blue is absolutely lightfast and extraordinarily stable. The stability of cobalt salts at high temperatures makes them the standard for blues used in ceramics and glassware.
Toxicity
Cobalt salts are toxic. Avoid respiratory and skin contact. Soluble cobalt may cause irritation and allergic reactions through contact with the skin. It is considered a possible carcinogen.
History
Since ancient times, smalt blue has been used to colour glass and ceramics. Cobalt salts, which give smalt its characteristic blue colour, were identified in the 18th century. Techniques for manufacturing Cobalt Blue, a chemically pure salt of cobalt and aluminum oxide, were developed in 1802.
Pigment Name: PBr7 Raw Sienna
Classification: Earth
Chemical Composition: Hydrated iron oxide
Properties
Raw Sienna is a moderately dull deep earth yellow with medium tinting strength and excellent transparency. It is one of the essential permanent artists' pigments and is made from a form of limonite clay whose yellow-brown colour results from ferric oxides. Raw Sienna is preferable to Yellow Ochre for creating flesh tones due to its higher subtlety of colour when mixed with white. It makes a bright Ochre when mixed with Cadmium Yellow and creates greens and grays when mixed with Ultramarine. Raw Sienna dries quickly.
Permanence
Raw Sienna has good permanence.
Toxicity
Raw Sienna has no significant hazards.
History
Raw Sienna has been a pigment since prehistoric times, although its current name originated during the Renaissance. It comes from Siena in Italy and is short for terra di Siena, meaning the earth of Siena. Sienna was famous for mining and producing earth pigments from the Renaissance until World War II. Due to the depletion of clay deposits in Tuscany, Italian sienna now comes from other areas, including Sicily and Sardinia.
