Winsor & Newton Professional Watercolor - Aureolin Hue, 14 ml Tube

Pigment Information

This color contains the following pigments:

PBr7-Raw Sienna

PY151-Benzimidazolone Yellow

Pigment Name

PBr7-Raw Sienna

Pigment Type

earth

Chemical Name

hydrated iron oxide

Chemical Formula

α-FeO3+(OH) or Fe2O3

Properties

Raw Sienna is a moderately dull deep earth yellow with medium tinting strength and excellent transparency. It is one of the basic permanent artists' pigments and is made from a form of limonite clay whose yellow-brown color results from ferric oxides. Raw Sienna is preferable to Yellow Ochre for creating flesh tones, due to its higher subtlety of color when mixed with white. It creates 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.

History

Raw Sienna has been used as a pigment since prehistoric times, although its current name came about during the Renaissance. It comes from the city of Siena, in Italy, and is short for terra di Siena, meaning earth of Siena. Sienna was famous for the mining and production of earth pigments from the Renaissance until World War II. Due to the depletion of clay deposits in Tuscany, Italian siennas now come from other areas, including Sicily and Sardinia.

Pigment Name

PY151-Benzimidazolone Yellow

Pigment Type

oranic, monoazo

Properties

Benzimidazolone Yellow is a greenish yellow pigment with dull tints and an average drying time. It mixes very cleanly. It mixes cleanly with both Phthalo Green and Titanium White. Although more expensive than many Hansa and Diarylide pigments, its mixing properties, durability, and lightfastness have won it many customers.

Permanence

Benzimidazolone Yellow has excellent lightfastness and durability. This has made it an extremely important pigment in the printing industry, for applications where lightfastness is a primary consideration. Though it is not absolutely lightfast, it ranks extremely well among organic yellows.

History

The benzimidazolone group of pigments was developed and patented in 1960 by Hoechst A.G., a German chemical manufacturer that was a forerunner of the pharmaceutical company Aventis.