Scientific Examination of Art Modern Techniques in Conservation and Analysis (2005) / Chapter Skim
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Techniques and Applications - Analytical Capabilities of Infrared Reflectography: An Art Historian’s Perspective--Molly Faries
Techniques and Applications - Analytical Capabilities of Infrared Reflectography: An Art Historian’s Perspective--Molly Faries
Pages 85-104
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From page 85... ...
Techniques and Applications
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From page 87... ...
The paintings and drawings mentioned in this text derive from different art historical periods, from early Netherlandish paintings of the fifteenth and sixteenth centuries to works by later artists such as Rembrandt and Vincent Van Gogh. Researchers in this field now need to recognize the expanding capabilities of infrared imaging and at the same time define more precisely the appropriate parameters of its use.
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From page 88... ...
cameras with sensitivity close to that of visible light, some of which have been recommended for use in conservation (Meyer and Raquet, 2002) , to more advanced focal plane arrays based on materials that were declassified in the 1990s, such as indium gallium arsenide or platinum silicide.
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From page 89... ...
(Both cameras are Stirling-cooled 640 × 480 platinum silicide focal plane arrays with digital and video output, outfitted with Nikon f 3.5, 55 mm lenses, so that the broadband spectral response ranges from 1.1 to 2.5-2.6 µm. For the Mitsubishi camera belonging to the Rijksuniversiteit Groningen, images are captured with Arte software and assembled with Panavue.)
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From page 90... ...
A second example can demonstrate how high-resolution imaging can bring out the character of an underdrawing. Platinum silicide focal plane arrays are capable of very sharp images, equal to and sometimes better than the resolution of the best IRR vidicons (van der Weerd et al., 2001)
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From page 91... ...
This is a fairly well-known phenomenon, and can occur with any one of the infrared imaging devices currently available. Recent infrared study of a Nativity of Christ from the workshop of Jacob Cornelisz van Oostsanen (Utrecht, Centraal Museum)
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From page 92... ...
The drawback, however, is that the closer the imaging approaches visible light, the more opaque are greens, blues, and white, and the more restricted is the view of the underdrawing. Most infrared imaging, in fact, falls between the two extremes mentioned above and the case described here.
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From page 93... ...
93 ANALYTICAL CAPABILITIES OF INFRARED REFLECTOGRAPHY FIGURE 2 Same detail as Figure 1. Digital composite of IRR reflectograms at 0.9-1.6/2 µm, showing elaborately worked out underdrawing (IRR and digital composite: Molly Faries)
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From page 94... ...
. Digital composite of IRR reflectograms at 0.9-1.6/2 µm in which underdrawing appears in the sleeves and robe of Joseph (IRR and digital composite: Molly Faries)
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From page 95... ...
95 ANALYTICAL CAPABILITIES OF INFRARED REFLECTOGRAPHY FIGURE 4 Same detail as Figure 3. Digital composite of IRR reflectograms at 1.1-2.5 µm in which the underdrawing becomes partially or totally transparent (IRR and digital composite: Molly Faries)
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From page 96... ...
These are then used to generate a false color infrared image using the color channels of Adobe Photoshop. Inks such as iron gall inks become transparent in this range of infrared light, but in false color infrared the differences in drawing materials and changes in condition can still be detected.
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From page 97... ...
Although Xradiography might seem the method of choice to elucidate these overlapping paint stages, infrared reflectography actually imaged some of the underlying forms in more detail. In X-ray the shape under the background sky could hardly be discerned (either because it was painted extremely thinly or with little dense paint, such as lead white)
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98 SCIENTIFIC EXAMINATION OF ART FIGURE 5 Anonymous German Master, Crucifixion, Houston, Museum of Fine Arts (Photo: Molly Faries)
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From page 99... ...
Some scholars still believe both paintings are by Rembrandt, but others now consider the Nuremberg painting to be the authentic Rembrandt, and The Hague painting the work of a studio assistant or other anonymous seventeenth-century master (see articles by Edwin Buijsen, Jørgen Wadum, and Eric Jan Sluijter in the 2/4 issue of volume 114 [2000] of the journal Oud Holland)
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From page 100... ...
. They concern several paintings by Vincent Van Gogh, although the current findings would in theory apply to any painting with lighter colors on the surface and darker colors in underlying forms.
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From page 101... ...
The underlying portrait also registers in X-radiography. Both X-ray and infrared reveal the basic shape of the portrait, but the infrared image provides additional information about dark modeling strokes around the mouth and eyes and in the hair.
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From page 102... ...
. this case infrared has imaged at least three unseen stages in the painting: an underlying composition, along with the forms of an as-yet-unidentified intermediate stage, and the perspective frame for the surface landscape, which has been applied over a presumably very thin layer of lead white.
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From page 103... ...
In addition, wavelength response itself is not always an absolute factor. Tests done with some indium gallium arsenide focal plane arrays have shown that the high quantum efficiency of these cameras can improve their performance (van Asperen de Boer, 2003)
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From page 104... ...
There is thus every reason to pursue the systematic cataloguing of painting collections as well as larger comparative studies using infrared, and to encourage interdisciplinary research that combines the expertise of technical art historians with that of research-oriented painting conservators and scientists who have a nuanced understanding of art. This text is based on the paper given at the Arthur M
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