AMSTERDAM.- Was Vincent van Gogh first and foremost an impulsive genius? How well have Van Gogh’s colours withstood the ravages of time? And did Van Gogh make a painting of his brother Theo after all? To start with the case of ‘Vincent/Theo’, according to prevailing opinion, Vincent van Gogh (1853-1890) never painted his brother Theo, his confidant and staunchest ally. But the two brothers looked quite similar. Now, the Van Gogh Museum’s senior research Louis van Tilborgh is convinced that one of the many ‘self-portraits’ by Vincent van Gogh is in fact a portrait of his brother Theo. This conclusion is based on a number of striking differences between Theo’s en Vincent’s features. Theo’s portrait, made in 1887, shows a man with shaved cheeks. Theo’s beard is not ‘red’ like Vincent’s, but more ochre. On top of that, this man’s ear has a fine rounded s