Hidden art revealed

A glimpse of a rare self-portrait by one of Australia’s most highly regarded artists has emerged from what appeared to be a blank canvas—thanks to researchers at the Australian Synchrotron.

A rare Streeton self-portrait, revealed in this image of zinc atoms. The highest concentrations are in the white of Streeton’s collar and the fairness of his face because zinc is used in the white pigment. Credit: Daryl Howard
A rare Streeton self-portrait, revealed in this image of zinc atoms. The highest concentrations are in the white of Streeton’s collar and the fairness of his face because zinc is used in the white pigment. Credit: Daryl Howard

A glimpse of a rare self-portrait by one of Australia’s most highly regarded artists has emerged from what appeared to be a blank canvas—thanks to researchers at the Australian Synchrotron.

Early in the 20th century, Sir Arthur Streeton, a renowned Australian landscape artist, painted over a self-portrait with a heavy layer of white lead paint in order to reuse his canvas.

The paint makes it impossible to see underneath, even with modern X-ray techniques.  So there the painting sat for years, at the National Gallery of Victoria (NGV).

Enter Dr Daryl Howard, his team at the Australian Synchrotron, and his colleagues from CSIRO and NGV, who used X-ray fluorescence spectroscopy to analyse the painting, revealing the precise location of the metal atoms in a 25- megapixel image.

Using this map of metal atoms, the scientists were able to establish where on the canvas certain paint pigments were concentrated.

For example, the element zinc is the main ingredient of a pigment used in oil painting called Zinc White.

“By tracing a map of the concentrations of zinc in the painting, we can start to see the white of Sir Streeton’s collar and the fairness of his face,” Daryl says.

“Anywhere else in the world, it would have taken a year to scan this painting—here it takes a day, because of a special detector called Maia, developed at the Synchrotron with CSIRO and Brookhaven National Laboratory in the US.”

Daryl is now working with a computer programmer to come up with a better model to match patterns of atoms with actual pigments.

“We’re working towards using a ‘Photoshop on steroids’ that will be able to fully reproduce these hidden artworks.”

Photo: A rare Streeton self-portrait, revealed in this image of zinc atoms. The highest concentrations are in the white of Streeton’s collar and the fairness of his face because zinc is used in the white pigment.
Credit: Daryl Howard

Australian Synchrotron, Daryl Howard, Daryl.Howard@synchrotron.org.au, www.synchrotron.org.au

National Gallery of Victoria, David Thurrowgood, david.thurrowgood@ngv.vic.gov.au, ngv.vic.gov.au