The National Galleries of Scotland has discovered what is almost certainly abr previously unknown self-portrait by Vincent Van Gogh.br Hidden from view for over a century, the self-portrait is on the back of the canvasbr with Head of a Peasant Woman and is covered by layers of glue and cardboard.br NGS experts believe these materials were applied ahead of an exhibition in the earlybr br twentieth century. Van Gogh often re-used canvases to save money. However,br instead of painting over earlier works, he would turn the canvas around and work onbr the reverse.