Tempera and Technique

Detail of Christ's blue garment from "Scourging of the Four Crowned Martyrs"

Tempera Paint

Derived from the Latin word temperare, which means to mix or blend, tempera paint is an egg, gum or glue based paint which is thinned by water. [1] Gerini would have been using an egg-based tempera paint. Ground pigment was combined with egg and water for color. Cennino Cennini, a contemporary of Gerini’s who penned the instructional book Il Libro dell’Arte, recommended using an egg yolk specifically for painting of faces to create a natural complexion, which is likely what Gerini himself would have done. [2]

Detail of yellow drapery from "Scourging of the Four Crowned Martyrs"

Use of Color

The color pigments used in the 14th century would have come from earth, mineral sources or the artificial mixture of chemicals. [3] Gerini would have used a mixture known as verdaccio, which consists of black, white, and yellow pigments, to create a gray-yellow tone for the faces in the painting. [4] This would have been combined with a red pigment, such as red lake for highlights. This pigment was also likely used for the droplets of blood on the torsos of the martyrs. Traditionally, blue was the most expensive color, whether it be the famous ultramarine or another variation of the color. [5] Therefore, the fact that the only large area of blue in the panel is the garment of Christ above the scene of the scourging demonstrates the importance of his presence in the painting.

Depth of Drapery

Unlike oil paint, tempera dries quickly, meaning that it must be applied in one stroke. [6] This makes creating depth and variety of tones more difficult. A technique which can be identified in “Scourging of the Four Crowned Martyrs” is cangiante, the changing from one color to another in order to create the effect of light on a painted object. [7] In this case, the object is the drapery of garments worn by the Roman official and his men. The clothing of the man holding a weapon in his hand is given realistic form by the use of two different yellow pigments. Although it is not clear which specific pigments were used, two frequently used and likely pigments are yellow earth and lead-tin yellow. [8]

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1. Lindley, Phillip. Making Medieval Art. Donington: Shaun Tyas, 2003. Print.

2. Cennini, Cennino. Cennino Cennini's Il Libro Dell'arte: A New English Translation and Commentary with Italian Transcription. Trans. Lara Broecke. London: Archetype Publications, 2015. Print.

3. Sultan, Altoon. The Luminous Brush: Painting with Egg Tempera. New York: Watson-Guptill Publications, 1999. Print.

4. New, Britta. “Niccolò Di Pietro Gerini's ‘Baptism Altarpiece’: Technique, Conservation and Original Design.” National Gallery Technical Bulletin, vol. 33, 2012, pp. 27–49.

5. Benton, Janetta Rebold. "Materials, Methods, and Masterpieces of Medieval Art". 2009. Print.

6. Lindley, Phillip. Making Medieval Art. Donington: Shaun Tyas, 2003. Print.

7. New, Britta. “Niccolò Di Pietro Gerini's ‘Baptism Altarpiece’: Technique, Conservation and Original Design.” National Gallery Technical Bulletin, vol. 33, 2012, pp. 27–49.

8. Merrifield, Mary P. Medieval and Renaissance Treatises on the Arts of Painting: Original Texts with English Translations. Mineola (N.Y.): Dover, 1999. Print.