Stubborn layers of paint had kept them hidden for several decades, but the
bluish, purplish and reddish hues of a 1919 painting by 20th-century artist
N.C. Wyeth have finally come to light, thanks to cutting-edge technologies developed
at the Cornell High Energy
Synchrotron Source (CHESS).
 | | Scientists at CHESS used confocal X-ray fluorescence to extract the colors of a painting by N.C. Wyeth that had been hidden under another painting. Christina Bisulca/University of Delaware |
The careful visualization of a Wyeth magazine illustration depicting two men
engaged in a brawl, only known previously in black and white, was publicly unveiled
Aug. 19 at an American Chemical Society symposium by chemist and art conservation
expert Jennifer L. Mass, M.S. '92, Ph.D. '95.
Mass, who collaborated on the Wyeth project with CHESS senior research associate
Arthur Woll and art conservators Christina Bisulca, Noelle Ocon and Matt Cushman,
described the powerful X-ray technology used to unveil the old painting, which
Wyeth had painted over in about 1923 with his work "Family Portrait."
CHESS scientists, led by Woll, developed a technique called confocal X-ray
fluorescence that harnesses the brilliant X-rays from the National Science Foundation-supported
CHESS to deal specifically with the problem of painted-over paintings. They
teamed with Mass, senior scientist at Delaware's Winterthur Museum and Country
Estate, to study "Family Portrait" after it was discovered 12 years
ago that a second work, the scene of a dramatic struggle from a 1919 Everybody's
Magazine article titled "The Mildest Mannered Man," lay underneath
it.
Their device focuses an X-ray beam onto a painting and collects the fluorescent
X-rays given off by the chemicals in the various layers of paint. Each color
of paint produces a unique fluorescence spectrum, like a chemical fingerprint,
which can then be mapped to reconstruct the original color schemes in the hidden
painting.
Confocal X-ray microscopy isn't new; it had been tried in Europe several years
ago, but mostly on scientific specimens, said Sol Gruner, CHESS director and
professor of physics.
"We built a setup specifically to look at large works of art," Gruner
said.
The result of the CHESS project was the discovery of a painting once thought
to be lost, two scientific papers describing the new confocal X-ray techniques
-- and a few surprises.
For example, one might expect the burning furnace plume depicted in the rightmost
part of the painting to glow a brilliant orange, Gruner said. As it turns out,
Wyeth used a more subtle tone.
"The colors are quite pale, something that was surprising to us, and there
were much more muted yellows and oranges, and more prevalent pinks and violets
then we were expecting," Mass said.
The collaboration between art conservators and CHESS scientists is growing,
Gruner said, with several other projects in the pipeline that involve specific
works of art as well as old manuscripts.
Confocal X-ray fluorescence is a slow, arduous technique; scanning a portion
of a painting the size of a quarter takes nine hours. A project at CHESS is
also ongoing to look at ways to speed up this process, which would allow more
art historians to access the technology, already applied in such disciplines
as biology, archaeology and dendrochronology, said Ernie Fontes, CHESS assistant
director.
"Confocal X-rays on paintings is still a very specialist niche,"
Fontes said.
Even so, Gruner expects that other synchrotron facilities will soon begin operating
instruments for art conservation, given that the confocal technology is well
known and accessible to synchrotron scientists.
"Our primary role in this, which is common for CHESS, is to lead by example,"
Gruner said.
Posted August 20th, 2009
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