Paris, July - August 1887
During his time in Paris (1886-1888), Van Gogh painted more than 20 self portraits. He probably had very little money for models. That led him to take himself as an object of study. Here he portrays himself as an artist in his blue smock-frock. This was what he wore when painting.
Van Gogh painted this on the back of a Study for ‘The Potato Eaters’, which he had made earlier in Nuenen (NL). By doing that, he avoided the costs not only of a model but also of expensive canvas.
(https://www.vangoghmuseum.nl/en/collection/s0135V1962v)
Van Gogh painted over 30 self portraits between the years 1886 and 1889. His collection of self portraits places him among the most prolific self portraitists of all time. Van Gogh used portrait painting as a method of introspection, a method to make money and a method of developing his skills as an artist.
(http://poulwebb.blogspot.nl/2013/05/vincent-van-gogh-self-portraits.html)
See van Gogh's self portraits in chronological order at http://www.wga.hu/html_m/g/gogh_van/16/ .