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Sienna [500 g bag] (17.6 oz.)
Item No: 460:300500
Category: 29
Price:
$22.50
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Quantity:
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Description:
Common Names: Raw Sienna, Siena-erde, Terre de Sienne, Terra di Siena Color: Brown Colour Index: Pigment Brown 7 (77491) (77492) (77499) ASTM Lightfastness: Oil: I Acrylics: I Watercolor: I
Sienna is hydrated ferric oxide closely resembling yellow ochre (See Gold Ochre) by its composition. The content of hydrated iron oxide in sienna varies from 40 to 70%. The differences in color between ochre and sienna, is most likely due to the degree of hydration, or quantity of water bonded to its ferric oxide content. The name sienna likely derives from the early source of this reddish brown earth near Siena, Italy. The most famous varieties of sienna are from Tuscany and the Hartz. These pigments are basically composed of the minerals goethite and hematite associated with varying proportions of mineral impurities such as clay, chalk and silica. In the European part of Russia the most widely known sources of sienna are in the Kudinovskoye deposit in the Moscow region and the Ukholovskoye deposit of Ryazansk province.
Origin: Our sienna comes from the deposit near Moscow. It is especially noted for its rich golden brown color and transparency. The name raw sienna comes from the need to distinguish it from burnt sienna, which is sienna that has been calcined or heated in ovens. Sienna has been used as a pigment since prehistoric times.
Permanence and Compatibility: Sienna does not react with other pigments and is effectively used in fresco, oil, tempera and watercolors. It is considered to be permanent with medium tinting strength and excellent transparency. It does not react with solvents, and is indifferent to alkalis, but are partially soluble in acids.
Absorption and Grinding: Sienna requires the largest proportion of oil of any other pigment to make it into a satisfactory oil-based paint. The finished paint will contain only 30% pigment.
Toxicity: The pigment is considered non-toxic, but care should always be exercised when handling the dry powder pigment so as not to inhale the dust.
 Read cautions about handling pigments
500 gram bag
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