Lines and Shapes

• Botticelli used lines, contours and contrasts to define his subjects and spaces. He painted with egg tempera, a type of paint made by mixing natural pigments with egg yolks. Because it dries almost instantly, egg tempera cannot be blended into shapes of graded color that define volume and delineate forms. Botticelli relied instead on dark outlines and dramatic color contrasts to distinguish shapes.
  
  

Layering Glazes

• Most of Botticelli's works were painted on wooden panels coated with a layer of gesso, a chalky surface preparation or primer. He would often, but not always, apply a traditional imprimatura, or a light-tinted wash, before beginning to paint. Botticelli used the traditional technique of applying egg tempera in thin layer after thin layer. Each thin coat of paint, or glaze, changes the effect light has on the color. Some of Botticelli's paintings show delicate traces of crosshatching, or changing the direction of brush strokes with different layers of paint. Crosshatching creates a molded, three-dimensional effect.
  
  

Oil and Water

• Botticelli was able to create different effects by adding oil or water to his paint. He used tempera mixed with oil, known as tempera grassa, for fuller, stronger more opaque colors. Tempera diluted with water allowed him to create translucent, glass-like glazes of colors. The transparent drapery and veils worn by many of his subjects were painted with layers of diluted white glaze. As tempera dries, colors soften and fade. Botticelli often returned them to their original hues by applying a generous coat of varnish.
  
  

Gold Details

• Botticelli was apprenticed to a goldsmith before joining the studio of Filippo Lippi and gold is used as a decorative element in many of Botticelli's paintings. Shell gold, or ground, powered gold mixed with egg whites, is used as a dramatic accent on the clam shell in "The Birth of Venus." Botticelli also used brushstrokes of shell gold to highlight the deep-green foliage found in some of his work. He used a technique called sgrafitto to give a delicate gold ornamentation to veils and drapery. With sgraffito, a layer of gold leaf is applied to the primed canvas or panel and covered with paint. A thin wooden stick is used to scratch out a design that appears as a decorative gold pattern on the cloth.