HOUSTON -

A Rice University professor played an important role in helping to identify a painting once believed to be a fake as an authentic painting by Vincent van Gogh.

The painting "Sunset at Montmajour" was unveiled Monday at the van Gogh Museum in Amsterdam as a major discovery and genuine product of the artist.

The work of art once considered a fake was stored in an attic and then held in a private collection according to reports.

Don Johnson, the J.S. Abercrombie Professor Emeritus of Electrical and Computer Engineering at Rice, performed an X-ray analysis of the canvas behind "Sunset at Montmajour."

"I have been working with the van Gogh museum for five years now and developed this technique. If they think a painting may be a Van Gogh they send the X-rays to me and I send the results back," said Johnson.

The Rice professor found the painting matched a similar canvas on a Van Gogh painting, The Rocks, at Houston's Museum of Fine Arts.

Art experts from the Van Gogh Museum traveled to Houston to do a technical examination of the Van Gogh painting in Houston.

"The canvas characteristics are extremely similar. I think both cut from the original piece of canvas but one cut from over here and one cut from this side," explained Johnson.

Johnson who is well known in the art world for his analysis of canvas used by the masters said he received an early morning email Monday to advise him of the official announcement to the international press.

He and a colleague at the University of Arizona developed the computer program he used to analyze aspects of the canvases behind the paintings that can not be seen in any other way.

"Right now I am the only person in the world who does this kind of analysis," said Johnson.

The process counts the thread density in a canvas through X-rays to reveal details about materials used creating a canvas "fingerprint" for art historians.

"It provided a piece of the puzzle for the people at the Van Gogh museum to study the painting," said the Houston professor.

A cover story about the discovery will appear in the October issue of the Burlington Magazine which credits Johnson among others for their analysis of the painting.

"Sunset at the Montmajour" is the first full sized canvas by Van Gogh discovered since 1928.