BACKGROUNDER: CONSERVATION TECHNIQUES AND DISCOVERIES
Art and science have come together in the exhibition Bellini, Giorgione, Titian, and the Renaissance of Venetian Painting to examine the creative process of many of the featured artists. Conservators and scientists employ x-radiography, infrared reflectography, and microscopy to reveal what lies beneath the surface of paintings, often making new discoveries about the development of specific works.
X-RADIOGRAPHY AND GIORGIONE’S PORTRAIT OF A WOMAN
X-radiography, a well-known diagnostic tool in the medical field, is used by
conservators to determine how artists applied different layers of paint to
create an image. X-rays penetrate through paint layers and record on film
the atomic weight or density of the various materials present. This technology
reveals changes, such as figure pose and placement, costume details, or background
composition, the artist made during the process of painting.
For example, in Giorgione’s Portrait of a Woman ("Laura") (1506), x-radiographs show that Giorgione modified his design during the course of painting. The positioning of a sheer veil across the woman’s shoulders changed, as did the placement of laurel leaves in the background. Giorgione’s repeated reworking of the laurel leaves indicates his concern with the motif that gives the picture its name. The x-radiograph also shows that in the 18th century the painting was cut down to an oval format and was later reconstituted.
INFRARED REFLECTOGRAPHY AND TITIAN’S VIRGIN AND
CHILD
Infrared reflectography is a complementary procedure to x-radiography, and
is used by conservators to study the preliminary outline of the composition
with which Venetian artists began their paintings. This rough sketch beneath
the paint layers is normally hidden from our view. However, most paints are
fully or partially transparent to infrared radiation, permitting cameras
with an infrared detector to capture an image of the underdrawing. Sometimes,
infrared reflectography can reveal changes in the paint layers that are invisible
to x-radiography.
The infrared reflectogram of Titian’s Virgin and Child ("Gypsy Madonna") (c. 1511) reveals several differences between the underdrawing and the finished work, including the positioning of the child’s shoulders. At an early stage, the child faces directly toward the viewer, while in the finished work his shoulders are turned to the side. The original positioning of the head, illustrated in the reflectogram, demonstrates the influence of Titian’s teacher, Giovanni Bellini, as it closely resembles Bellini’s Virgin and Child, now in the Detroit Institute of Arts.
MICROSCOPY AND GIORGIONE
Microscopy is the technical process of analyzing a minute cross section of
a paint sample and examining its composition and layers under a microscope.
This type of analysis can be used to reveal compositional changes. In Giorgione’s
Portrait of a Woman, analysis of paint cross sections revealed a layer of
pale blue paint in the area surrounding the laurel leaves. In the finished
work this area is dark brown, but at one stage the work may have had a blue
sky and distant landscape, reminiscent of the background of Leonardo da Vinci’s
Ginevra de’ Benci (c. 1474/1478) in the collection of the National
Gallery of Art.
Microscopic analysis has also revealed that Venetian artists were at the forefront of layering different colors of translucent paint on top of each other to modulate tones and create novel colors. They made use of additives, such as glass, white earths, or finely ground quartz, to create semi-transparent paints This was found in the cross section taken from the Virgin’s mantle in Giorgione’s Adoration of the Shepherds (c. 1500).
There will be a special installation in the exhibition devoted to the materials and techniques of the artists, as well as several explanatory wall labels with technical images throughout the exhibition. Technical Studies of Painting Methods by Elke Oberthaler and Elizabeth Walmsley, an essay from the exhibition catalogue, is available online. Please visit: http://www.nga.gov/press/exh/191/methods.pdf
This exhibition is made possible by Bracco, an international leader in diagnostic imaging.
It is supported by an indemnity from the Federal Council on the Arts and the Humanities.
The exhibition was organized by the National Gallery of Art, Washington, and the Kunsthistorisches Museum, Vienna.
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