An Investigation of Paintings By and Attributed to Velázquez: Javier Portús, Head of the Department of Spanish Paintings at the Museo Nacional del Prado, Madrid, was invited in June 2014 to study The Met’s paintings by Velázquez and his circle. In collaboration with Dorothy Mahon, Conservator, Department of Paintings Conservation, paintings were brought to the conservation studio for close comparative examination (see fig. 5 above). The study included all of the paintings in The Met by or attributed to Velázquez, but for stylistic and technical reasons eventually focused on the well-documented portrait of
Juan de Pareja (The Met,
1971.86). The
Portrait of a Man entered the collection as gift of Henry Marquand in 1889 as a self-portrait by Velázquez. Since 1914, however, both the identification of the sitter and the attribution have been questioned, with most scholars regarding it as by someone closely associated with the artist. The possibility to closely compare this portrait in optimal circumstances with securely ascribed paintings, as well as the opportunity to gather new technical information, has resulted in a more subtle consideration of its attribution. The investigation included updated technical imaging using infrared reflectography and x-radiography. The surfaces of the paintings were examined using a high magnification stereomicroscope, and paint samples mounted in cross section were examined with polarizing light microscopy (PLM), Raman microscopy, as well as scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS). Dorothy Mahon selected the paint samples, made the x-radiographs, and worked closely with Javier Portús to put the technical data into context. Silvia Centeno and Federico Caró, Research Scientists, Department of Scientific Research, carried out the analysis of the paint samples. Evan Read, Manager for Technical Documentation, assembled the infrared reflectography captures. Juan Trujillo, Imaging, took all photographs mentioned below unless otherwise indicated.
Technical Evidence Considered in Support of Reattribution: Technical analysis and technical imaging supporting consideration of a reattribution of this painting is presented along with comparative details of other portraits, highlighting similarities in artist technique. In addition to
Juan de Pareja, the comparative paintings illustrated include Velázquez’s
Portrait of a Man from the Jules Bache collection (The Met,
49.7.42; fig. 16) and
Ferdinando Brandani (Museo Nacional del Prado, Madrid; P7858; fig. 12). As detailed below, the microscopic similarities of the ground preparations and paint layers of the Marquand
Portrait of a Man to those of
Juan de Pareja suggest that the former was also painted in Rome (fig. 6), dramatically shifting any discussion of attribution.
The Canvas Support: The supports of
Juan de Pareja and the
Portrait of a Man are characteristic of the coarse canvas available during this period in Italy, and differ from the finer weave used by the artist in Madrid (fig. 7). The canvas support of
Juan de Pareja consists of 9.7 vertical threads and 10.1 horizontal threads per square centimeter. The canvas support of
Portrait of a Man consists of 6.6 vertical threads and 10 horizontal threads per square centimeter.
Technical Analysis of Ground and Paint Layers: The particle size and pigment mixtures in the paint layers and ground structures of
Juan de Pareja and
Portrait of a Man are similar (fig. 8). Both canvases were prepared with a first sizing layer (
aparejo) consisting of calcium carbonate obtained from washed wood ash bound in glue. Scanning Electron Microscopic Analysis (SEM) of calcium carbonate (calcite) in both sizing layers reveals the particles have a similar composition and morphology, which is characteristic of calcite obtained from washed wood ash. The priming layer (
imprimación) in both paintings is a medium warm reddish-brown color consisting of a mixture of white, red, and black pigments. For the
Portrait of a Man, the artist applied an additional layer of red iron earth. The red earth layer does not contain lead white, which is typically found in Madrid red earth grounds (
tierra de esquivias). Velázquez used both double grounds and varied the color of his ground throughout his career.
What is Washed Wood Ash and Why is the Detection of This Material Important?: The source of the calcium carbonate detected in the ground layers of
Juan de Pareja and
Portrait of a Man was obtained from washed wood ash. This calcium carbonate is obtained as a byproduct of the extraction of lye (potassium hydroxide)—which for centuries was the essential and readily available material used for washing clothes and making soap—from wood ash. The sludge that remains after ashes are rinsed with water during lye extraction contains a high percentage of calcium carbonate (calcite). The process of burning wood and subsequent rinsing of wood ash with water results in a material that contains uniquely formed calcium carbonate particles.[1] It is this calcium carbonate-rich byproduct that provides a useful artist material. Although the use of washed wood ash in the ground preparations of paintings is described in two artist treatises—by Francisco Pacheco (1564–1644), published in 1649,[2] and Antonio Palomino (1655–1726), published in 1715–25)[3]—the analytical detection and proof of the actual use of this material in seventeenth-century Spanish paintings is recent.[4] The distinction of calcium carbonate obtained from washed wood ash in the ground preparations is important because, since ancient times, artists have most commonly used other geologically available materials, such as chalk (calcium carbonate) and gypsum (calcium sulphate), for their ground preparations. In Italy and Spain, the most common material used in ground preparations is gypsum because it is an abundantly available geological material. In the northern parts of Europe, including the Netherlands, France, Germany, and England, chalk is the most commonly used abundantly available geological material. Until the recent detection of washed wood ash in the ground preparation of
Juan de Pareja, all reported examples are confined to paintings produced in seventeenth-century Madrid.[5] Therefore, the detection of washed wood ash in both
Juan de Pareja and
Portrait of a Man supports the assumption that the latter could also have been produced in Rome. To date, calcium carbonate obtained from washed wood ash has not been detected in a painting produced in Italy by an Italian artist. This is why the detection of washed wood ash in the ground of paintings made by a Spanish artist working in Italy is of interest, and suggests that Velázquez may have brought some painting materials with him to Rome. Because ashes are available everywhere, it cannot be ruled out entirely that Velázquez may have obtained calcium carbonate from washed wood ash in Italy. However, the quality of the washed wood ash detected suggests that this product may have been collected, refined, and resold as a commercial byproduct of the extraction of lye from wood ashes in Spain, where its pervasive use in the seventeenth-century in Madrid has been documented.[6] The eventual identification of this material in many more works of art in Spain, and possibly other locations, will lead to a greater understanding of this recycled material, as well as help us understand how widespread its use was throughout the world and over time.
Characteristics of Velázquez’s Technique: Characteristic artist changes to the collar and adjustments to the contours of the figure in
Portrait of a Man are visible in normal light as well as in the x-radiograph (fig. 9).
A comparison of details of
Portrait of a Man with
Juan de Pareja highlights areas on both portraits where Velázquez customarily uses a final, precise dab of light gray paint to distinguish between the lower edge of the hair and the upper part of the collar. Also visible are characteristic changes to the contours of the collar (fig. 10).
In
Portrait of a Man, a preliminary sketch in black paint is visible in both normal light and infrared imaging (fig. 11). A preliminary black sketch and adjustments to the collar are also present in Velázquez’s
Ferdinando Brandani (Museo Nacional del Prado, Madrid; P7858; figs. 12, 13).
In
Ferdinando Brandani and
Portrait of a Man, the passages where the hair meets the forehead is accomplished by a gray zone that facilitates the transition between the dark tones of the hair and the pinks of the flesh (fig. 14).
In the infrared reflectogram of
Portrait of a Man, the dark lines in the underlayer converging toward the chin and back of the collar are characteristic of the preliminary drawing Velázquez uses to position a head (fig. 15).
A comparison of the eyes in this painting with those in the
Portrait of a Man from the Jules Bache collection (The Met,
49.7.42), in both normal and infrared light, reveals a dark spot in the underpainting between the eyebrow and the upper eyelid that served to establish the coordinates for the position of the head, a working feature characteristic of Velázquez (fig. 17).
The eyes of both portraits are painted in a similar manner, with lightly traced eyebrows and a definitive gradation of color and light from the darker and denser area near the bridge of the nose to a lighter and thinner application near the temple (fig. 18).
Details of the mouths of this portrait and
Juan de Pareja, taken in the natural lighting of the conservation studio, reveal the great similarity of color and paint application (fig. 19).
Characteristic of Velázquez are the traces of paint in the background—present in the
Portrait of a Man and many of his other paintings—where the artist wiped his brush (fig. 20).
Dorothy Mahon, Conservator, Department of Paintings Conservation
February 20, 2019
[1] Federico Caró, Silvia A. Centeno, and Dorothy Mahon, “Painting with Recycled Materials: On the Morphology of Calcite Pseudomorphs as Evidence of the Use of Wood Ash Residues in Baroque Paintings,”
Heritage Science 6, no. 3 (2018).
[2] Francisco Pacheco,
El Arte de la Pintura, su Antiquedad y Grandeza, 1649, Book 3, p. 384.
[3] Antonio Palomino y Velazco,
El Museo Pictórico y Escala Óatica, 1715, Book 5, p. 51.
[4] Maite Jover de Celis and María Dolores Gayo, “This They Use in Madrid: The Ground Layer in Painting on Canvas in 17th-Century Mardrid,”
Making and Transforming Art, Technology and Interpretation, London, 2014, pp. 40–46.
[5] In 2016, subsequent to this study, washed wood ash was detected in a painting by the seventeenth-century Mexican artist Cristóbal Villalpando. Technical study of more paintings from this region is necessary in order to understand the extent to which this material was also used in New Spain. See Dorothy Mahon, Silvia A. Centeno, and Louisa Smieska, “Cristóal Villalpando’s Adoration of the Magi: a Discussion of Artist Technique,” LALVC 1, no. 2, forthcoming April 2019.
[6] See Jover de Celis and Gayo 2014.