Hidden beneath one of Vincent Van Gogh's paintings in his signature vivid style is a much more restrained portrait of what is thought to be a Dutch peasant woman painted by the artist in the early part of his career, when he lived in Nuenen in the Netherlands.
In late 1884, Van Gogh painted a series of heads of peasant models in their homes as a means of training his control over colour and light, and the woman discovered beneath Patch of Grass is likely part of this series.
What is significant about the discovery of the face is it shows the rapid evolution of his style and use of colour, as the two layers are estimated to be only painted two-and-a-half years apart, with Patch of Grass dated to 1887.
The painting was one of the first to be analysed with an X-ray technique pioneered by Dutch scientists Joris Dik and Koen Janssens, that can accurately determine the original pigments of the hidden painting.