Cybersleuth paints forgers into corner

[R.A. Hettinga]

<http://www.nzherald.co.nz/storyprint.cfm?storyID=3613252>


New Zealand Herald Online - Newspaper

Wednesday November 24, 2004

 Cybersleuth paints forgers into corner

 24.11.2004  - By STEVE CONNOR

 Scientists have created a computer that can tell the mathematical
difference between a genuine work of art and a forgery by analysing
features invisible to the human eye, paving the way to a new method of art
fraud detection.

 The computer can also distinguish between the contributions of apprentices
who collaborated on a well-known masterpiece officially attributed to a
single artist.

 Scientists said the technique meant academics could better understand the
hidden contributions of lesser-known artists.

 The researchers used a mathematical approach, analysing the statistical
likelihood that a particular brush or pen stroke was performed by the
artist.

 A similar mathematical approach powered by computer has been used to
analyse the words in famous texts to see whether they were the sole
creation of a well-known author.

 Henry Farid, associate professor of computer science at Dartmouth College
in Hanover, New Hampshire, said the technique could be applied to fine art
thanks to the widespread use of high-resolution digital imagery that
collects up to 2400 points of light in a single square inch of canvas.

 "We have been able to mathematically capture subtle characteristics of an
artist that are not necessarily visible to the human eye," he said.

 "We expect this technique, in collaboration with existing physical
authentication, to play an important role in the field of art
authentication.

 "Similar methods have been used to analyse works of literature.

 "We can find things in art work that are unique to the artist, such as the
subtle choice of words or phrasing and cadence that are characteristic of a
certain writer."

 Scientists program the computer with an artist's personal style of
painting or drawing, using digital images of masterpieces known to be the
work of the same painter. The machine can then decide whether a new work it
subsequently analyses is likely to be a forgery.

 Professor Farid and his colleagues analysed 13 drawings that had been
attributed - at least at some time - to Flemish artist Pieter Bruegel the
Elder. The computer successfully distinguished between eight paintings
known to be by the artist and five famous imitations by contemporary
artists, including some by artists who intended to commit a forgery.

 A second part of the research, reported in the journal Proceedings of the
National Academy of Sciences, analysed digital images of the Madonna with
Child by Italian Renaissance artist Perugino, who became famous for his
altar pieces.

 The faces of three figures on the left of the painting were found to be
the work of one artist, and the three on the right were different enough to
be the work of different artists, probably Perugino's apprentices, a common
practice in Renaissance art.

 The researchers say analysing brush and pen strokes mathematically will be
combined with other techniques, such as x-rays to see underneath a coat of
paint, in verifying a painting's authenticity.

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R. A. Hettinga <mailto: rah at ibuc.com>
The Internet Bearer Underwriting Corporation <http://www.ibuc.com/>
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