Mastering Raw Sienna: Advanced Techniques and Insights for Professional Oil Painters

As an oil painter, selecting the right colors for your palette is essential to creating successful works of art. Raw Sienna is a popular pigment that has been used by artists for centuries due to its unique qualities. In this article, we will explore the history, properties, uses, and techniques of Raw Sienna, and how it can enhance your oil painting practice.

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What is Raw Sienna?

Sienna is an earth pigment that contains iron oxide and manganese oxide. It is known for its yellowish-brown color in its natural state, which is called raw sienna. When heated, it transforms into a reddish-brown color called burnt sienna. The pigment derives its name from Siena, an Italian city-state, where it was extensively produced during the Renaissance period. Sienna, along with ochre and umber, is one of the oldest pigments used by humans, and it has been found in many ancient cave paintings. From the Renaissance onwards, it has been widely used as one of the most popular brown pigments by artists.

The first recorded use of the term sienna as a color name in English was in 1760, while the normalized color coordinates for sienna are the same as kobe, which was first used as a color name in English in 1924.

History of Raw Sienna

Sienna is a natural pigment that has been used for centuries by artists around the world. The ancient Romans were aware of its properties and used it in its natural form. The pigment was originally mined near Arcidosso, which was once under Sienese control and is now located in the province of Grosseto, southern Tuscany. It was referred to as terra rossa, terra gialla, or terra di Siena.

During the Middle Ages, artists like Duccio di Buoninsegna and others who lived and worked in and around the Republic of Siena used sienna pigments. Duccio used earth pigments until his death in the early 14th century.

The Renaissance artist Giorgio Vasari noted the pigment under the name terra rossa. Sienna became one of the standard browns used by artists from the 16th to 19th centuries, including Caravaggio and Rembrandt, who used all three earth colors in their palettes. Cross sections of Rembrandt's works reveal that he used variations of sienna to prime his paintings, especially in his later works.

Although sienna and its variations were used by these artists, the pigment was not commonly referenced by name in European sources until the mid-eighteenth century. By the 1940s, the traditional Italian sources of the pigment were nearly exhausted. Today, much of the sienna production occurs in the Italian islands of Sardinia and Sicily, as well as in the Appalachian Mountains and the French Ardennes in the small town of Bonne Fontaine near Ecordal. It is important to note that the chemical composition of the umbers produced in France is distinctly different from the original siennas.

In the 20th century, synthetic iron oxide began to be used to produce pigments. The labels on paint tubes indicate whether they contain natural or synthetic ingredients. The Colour Index Generic Name (CIGN) Pigment Yellow (PY 23) indicates natural raw sienna, while Pigment Red 102 (PR 102) indicates natural burnt sienna. Aspiring artists should be aware of these distinctions and choose their materials accordingly to achieve the desired effects in their artwork. The Colour Index for natural sienna can also be written as Pigment Brown 7 (PBr 7), as noted in Table 1 Suitable Pigment List of the ASTM D 4302 Standard Specification for Artists’ Oil, Resin-Oil, and Alkyd Paints. 

Today, Raw Sienna is still a popular color among artists due to its versatility and natural warmth.

Properties of Raw Sienna

Sienna is a type of clay that is rich in iron oxide, similar to other earth colors such as yellow ochre and umber. The most common iron oxides found in sienna are limonite and goethite, which have yellowish hues in their natural states. Additionally, sienna contains manganese oxide, making it darker than ochre. Aluminum oxides have also been found in sienna at low levels. When heated, limonite and goethite are dehydrated and partially transformed into hematite, which gives sienna its reddish-brown hue.[6] Raw sienna is lighter than raw umber, another clay pigment with iron oxide, but which has a higher content of manganese (5 to 20 percent), making it either greenish-brown or dark brown. When heated, raw umber becomes burnt umber, which is a much darker brown.

Raw Sienna has a number of unique properties that make it a popular choice among oil painters. These properties include:

• Warm, earthy tone: Raw Sienna has a warm, natural color that is reminiscent of the Italian countryside.

• High level of transparency: Raw Sienna is highly transparent, which makes it ideal for glazing and layering.

• Granular texture: Raw Sienna has a granular texture that adds depth and dimension to paintings.

• Low tinting strength: Raw Sienna has a low tinting strength, which means it can be used to tone down brighter colors without overpowering them.

• Lightfastness: Raw Sienna has excellent lightfastness, which means it will not fade over time.

Raw Sienna in Oil Painting

Raw Sienna is a versatile pigment that can be used in a variety of ways in oil painting. It can be used as a base color for flesh tones, as a natural earth color, or as a glaze to add warmth and depth to paintings.

When used as a glaze, Raw Sienna can create a warm, golden effect that is ideal for capturing the light of a Mediterranean landscape. It can also be used to create natural, earthy tones for landscapes, still lifes, and portraits.

Mixing Raw Sienna with Other Colors

Raw Sienna can be mixed with a wide range of colors to create unique shades and hues. When mixed with white, it creates a soft, warm tint. When mixed with blues, it can create a range of greens and cool browns. When mixed with reds, it can create warm, reddish-brown hues.

Raw Sienna in mixtures with Blue Ridge Yellow Ocher and Titanium White.

Raw Sienna in mixtures with Ultramarine Blue and Titanium White

Raw Sienna in mixtures with Alizarin Crimson and Titanium White

Raw Sienna in mixtures with Venetian Red and Titanium White

Techniques for Using Raw Sienna

Several techniques can be used when working with raw Sienna. These include:

• Glazing: Raw Sienna can be used as a glaze to create warm, golden effects. To do this, mix Raw Sienna with a small amount of oil and apply it thinly over a dried layer of paint. This will create a warm, transparent layer that adds depth and dimension to your painting.

• Dry brushing: Dry brushing is a technique where a dry brush is used to apply paint to the canvas, creating a textured effect. Raw Sienna is a great color to use for dry brushing, as its granular texture can create interesting effects.

• Washes: Raw Sienna can also be used to create washes, which are thin, transparent layers of color. To create a wash, dilute Raw Sienna with a small amount of solvent and apply it thinly to the canvas. This technique is great for creating soft, natural-looking backgrounds.

Tips for Using Raw Sienna

When using raw Sienna in your oil paintings, there are a few tips to keep in mind:

• Use it as a glaze: Raw Sienna is a great color to use as a glaze, as it is transparent and adds warmth and depth to your paintings. Apply it thinly over a dried layer of paint to create a warm, transparent layer.

• Mix it with other colors: Raw Sienna can be mixed with a wide range of colors to create unique shades and hues. Experiment with different combinations to find the perfect color for your painting.

• Use it for natural, earthy tones: Raw Sienna is perfect for creating natural, earthy tones in landscapes, still lifes, and portraits. Use it as a base color for flesh tones or to create warm, natural backgrounds.

• Experiment with techniques: There are several techniques you can use when working with Raw Sienna, such as dry brushing and washes. Experiment with these techniques to create interesting effects in your paintings.

Alternatives to Raw Sienna

If you're looking for an alternative to Raw Sienna, there are several options to choose from:

• Burnt Sienna: Burnt Sienna is a darker, reddish-brown version of Raw Sienna. It is a great alternative if you're looking for a warmer, richer tone.

• Yellow Ochre: Yellow Ochre is a natural earth pigment that has a similar warm, earthy tone to Raw Sienna. It is a great alternative if you're looking for a more opaque color.

• Raw Umber: Raw Umber is a natural earth pigment with a darker, cooler tone than raw Sienna. It is a great alternative if you're looking for a more neutral color.

• Transparent Yellow Iron Oxide: Transparent Yellow Iron Ooxide has many similarities in transparency and color to some Raw Sienna pigments.

How to Choose the Best Raw Sienna Oil Paint

When choosing a raw Sienna paint, there are a few things to consider:

• Quality: Choosing high-quality paint that is made with pure, natural pigments is more difficult these days because paint manufacturers use Sienna to designate a color rather than the pigment. Look at the label for the Colour Index Pigment Yellow 43 (PY 43) or Pigment Brown 7 (PBr 7) to ensure you buy the natural pigment. Many manufacturers 

• Brand: Look for a reputable brand that is known for producing high-quality paints.

• Consistency: Choose a paint that has a consistency that works for your painting style. Some artists prefer thicker paints, while others prefer thinner, more fluid paints.

Raw Sienna in Famous Artworks

Raw Sienna has been used in many famous artworks throughout history. Here are a few examples:

Giorgio Vasari, The Battle of Marciano in Val di Chiana (Battaglia di Marciano in Val di Chiana), 1570–1571, Fresco, 1300 x 760 cm, Comune di Firenze: Giorgio Vasari (1511–1574) used earth colors, including ochre and sienna, in his frescos, such this in the Hall of the Five Hundred at the Palazzo Vecchio in Florence. In his writings, Vasari referred to sienna as terra rossa.

Rembrandt van Rijn, Self-Portrait with Circles, c. 1665–1669, Oil on canvas, 114.3 cm × 94 cm (45.0 in × 37 in), Kenwood House, London: Rembrandt used all the earth pigments (sienna, ochre, and umber) to create his rich and complex browns.

Rembrandt van Rijn, The Night Watch, 1642, Oil on canvas, 363 cm × 437 cm (142.9 in × 172.0 in), Amsterdam Museum on permanent loan to Rijksmuseum in Amsterdam, Netherlands: Rembrandt used Sienna to create the warm, golden tones in the background of this iconic painting.

Johannes Vermeer, Girl with a Pearl Earring, c. 1665, Oil on canvas, 44.5 cm × 39 cm (17.5 in × 15 in), Mauritshuis, The Hague, Netherlands: Vermeer used Sienna to create the warm, natural skin tones of the girl in this famous portrait.

John Constable, The Hay Wain (Originally titled: Landscape: Noon), 1821, Oil on canvas, 130.2 cm × 185.4 cm (51+1⁄4 in × 73 in), National Gallery, London: Constable used Sienna in this famous painting to create the warm, earthy tones in the landscape.

Conclusion

Raw Sienna is a versatile and useful color for oil painters. Its warm, earthy tone and high level of transparency make it ideal for creating natural, realistic effects in landscapes, still lifes, and portraits. Whether you're a beginner or an experienced painter, Raw Sienna is a color worth adding to your palette.

References

Webster’s New World Dictionary of the American Language. College Edition. 1964.

Maerz, Aloys John., Paul, Morris Rea. (1930). A Dictionary of Color. United States: McGraw-Hill Book Company, Inc. p. 204; Color Sample of Sienna: p. 37 Plate 7 Color Sample E12

Maerz, Aloys John., Paul, Morris Rea. (1930). A Dictionary of Color. United States: McGraw-Hill Book Company, Inc. p. 197; Color sample of Kobe: p. 35 Plate 6 color sample K12

Helwig, Kate (2007). “Iron Oxides.” Artists’ Pigments. Vol. 4. Archetype Publications. ISBN 978-1-904982-234.

Wilcox, Michael (2002). Blue and yellow don’t make green. School of Color. pp. 172, 161. ISBN 0-9679628-7-0. Retrieved October 19, 2009.

Roelofs, Isabelle (2012). La couleur expliquée aux artistes. Groupe Eyrolles. p. 30. ISBN 978-2-212-134865.

Manasse, Andrea; Mellini, Marcello (2006). “Iron (hydr)oxide nanocrystals in raw and burnt sienna pigments.” European Journal of Mineralogy: 845. doi:10.1127/0935-1221/2006/0018-0845.

Burnet, John. A Treatise on Painting, in Four Parts: Consisting of an Essay on the Education of the Eye with Reference to Painting, and Practical Hints on Composition, Chiaroscuro, and Colour ; the Whole Illustrated by Examples from the Italian, Venetian, Flemish and Dutch Schools. United Kingdom: J. & J. Leighton, 1850. p. 4.

Bomfeld, David; Brown, Christopher; Roy, Ashok. (1988) Rembrandt—Art in the Making. Yale University Press. ISBN 978-0-300-06145-1.

Plesters, Joyce (1956). “Cross-Sections and Chemical Analysis of Paint Samples.” Studies in Conservation. 2 (3): 122–125. doi:10.2307/1505000.

Vasari, Giorgio. Lives of the Most Eminent Painters, Sculptors, and Architects.

Helwig, Kate. (1997). “A Note on Burnt Yellow Earth Pigments: Documentary Sources and Scientific Analysis.” Studies in Conservation. 42 (3): 181–188. doi:10.2307/1506714. ISSN 0039-3630.