In May, 2001, several
articles were published in newspapers about the authenticity
of a head and shoulders portrait of William Shakespeare
supposedly painted in 1603. This painting had belonged to an
Ontario family for generations. A scientific examination of
the portrait was carried out by the Canadian
Conservation Institute (CCI) in order to date it.
Only necessary tests are
performed when examining a painting using scientific
methods. Tree-ring dating of the wood panel on which it is
painted was performed by an expert from Hamburg. Tree-ring
dating determines when a tree was cut using the distance
between growth rings. His analysis revealed that the wood
was cut around 1597.
The fact that the panel was
the right age does not by itself verify the age of the
painting. Other tests needed to be performed. Radiographs,
similar to x-rays, revealed no other painting beneath the
original. Ultraviolet fluorescence photography demonstrated
that no retouching had been done to the painting after it
was finished.
One of the last set of tests
done by CCI, other than dating the paper label on the back
of the painting, involved analyzing the materials used to
paint the portrait. Microscopic paint samples are removed
and tested using a variety of techniques. If the analysis
revealed painting materials that were not used until the 19th
or 20th century, it could demonstrate that a
painting is a fake.
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