Beneath the Surface of a Late 15th-Century Spanish Treasure: The Altarpiece from Ciudad Rodrigo by Fernando Gallego and His Workshop
In September 2006, the Kimbell Art Museum's paintings conservation department began the first technical study of Fernando Gallego's Ciudad Rodrigo altarpiece, one of the most significant Spanish works of this kind created in the late 15th century. The Kimbell study endeavored to learn more about the workshop practices of Fernando Gallego, the famous painter from Salamanca, as well as those of his collaborator, Maestro Bartolomé. In late 15th-century Castile, master painters often worked together to produce major altarpieces. Even before the Kimbell study, differences in style and technique among the 26 existing panels had suggested to scholars that two independent workshops joined forces to take on the enormous Ciudad Rodrigo commission.
According to an early inscription on the framework, the altarpiece traditionally was dated to between 1480 and 1488. We now know that at least three panels were added several years later, because their imagery is based on woodcut illustrations from a book known as the Nuremberg Chronicle, which was published in Germany in 1493.
The technical study of the Ciudad Rodrigo panels—like the altarpiece's creation—was an ambitious project that required several colleagues' collaboration. At the Kimbell, Chief Conservator Claire Barry and her assistant Elise Effmann worked on all aspects of the examination, which included X-radiography and infrared reflectography. Inge Fiedler, conservation microscopist from the Art Institute of Chicago, conducted pigment analysis, using polarizing light microscopy, on a number of panels attributed to both artists. Fiedler took several pigment samples from areas with color notes in panels attributed to Fernando Gallego and his workshop. Michael Schilling and Joy Mazurek, conservators at the Getty Conservation Institute, conducted medium analysis on a selection of samples, using gas chromatography/mass spectroscopy. Peter Klein, dendochronologist (one who studies tree rings) from the University of Hamburg in Germany, identified the wood and joining methods used to construct the large panels.
Recent technological advances in infrared reflectography facilitated capture of images of preparatory underdrawings, an essential aspect of the artists' techniques. InfraCAM SWIR, manufactured by FLIR Systems, was used in this study. Since only small areas could be examined at a time, hundreds of exposures from each panel were taken to create infrared reflectogram mosaics of each painting's full composition. The individual exposures were then digitized and assembled on a computer using Adobe Photoshop software, eventually creating a complete record of these previously undocumented preliminary sketches.
The personal character of each artist's underdrawing effectively distinguished Fernando Gallego's work from that of Maestro Bartolomé; clear stylistic differences and working practices became apparent. Fernando Gallego, for example, made frequent color notations in drapery areas; no such inscriptions were found in the panels attributed to Maestro Bartolomé. The infrared examination also revealed that Bartolomé relied more heavily on prints and tracings, and made significant changes to his compositions as he developed his images.
Much of Fernando Gallego and His Workshop: The Altarpiece from Ciudad Rodrigo—Paintings from the Collection of the University of Arizona Museum of Art highlights the technical analysis of the altarpiece, including installation of the life-sized infrared reflectogram mosaics of 13 of the panels. Displayed on a light box, each underdrawing—never meant for the public eye—is visible for the first time in 500 years. Other galleries in this exhibition are devoted to the styles and techniques of the artists involved in the altarpiece's creation, as well as the creative changes each painter made between the drawing and painting phases of their works. Another gallery, devoted to the Kimbell conservation studio, identifies the technologically advanced equipment that made these discoveries possible. An essay that Barry authored, summarizing the technical study results, is included in the scholarly catalogue that accompanies the exhibition.