The great Dutch painter often wrote his new paintings on old canvas, on top of earlier works. According to art historians, more than a third canvases "secret" early versions of the same pictures or unknown work.

In particular, the canvas "of grass flap» (Patch of Grass), written by Van Gogh in Paris in 1887 and stored in Kreller-Muller Museum in Otterlo (the Netherlands), is still an enigma to art historians. Previous studies have shown paintings that under the top layer of paint may be hiding a portrait - with the traditional method of X-ray scanning XRR (X-ray radiation transmission radiography) managed to get the vague outlines of a female head. However, this method does not allow to obtain a clearer picture.

Scientists from the universities of Delft (The Netherlands) and Antwerp (Belgium) used to study the paintings " The flap of grass "a new technology, which is based on the use of synchrotron radiation and fluorescence spectroscopy.

Cloth scanned using synchrotron radiation source DORIS at an accelerating installation of DESY (Hamburg, Germany), with the measured intensity of fluorescence layers of paint. During the two days was scanned plot paintings, 17,5 x 17,5 cm, under which was previously detected a vague outline of the head.

As a result of scanning were obtained distribution of elements and pigments of the paint layer, which allowed to reconstruct the image with high accuracy. Scientists even managed to get a color picture of a female portrait distributions obtained by mercury and antimony, comprising some of the colors.

Presumably, a female head sketch was written by the artist in the period from October 1884 to May 1885 - this was the time Van Gogh painted a series similar to the manner of portraits of Dutch farmers in the village Nyuenen (Nuenen). Etudes further served to create his famous painting "The Potato Eaters."

According to researchers, this technique will allow more detailed study of the creative methods of Van Gogh and opens his previously unknown paintings and sketches.