Vincent Van Gogh's Painting With Tilt-shift Effect

The extent to which his mental illness affected his painting has been a subject of speculation since his death. Despite a widespread tendency to romanticise his ill health, modern critics see an artist deeply frustrated by the inactivity and incoherence brought about by his bouts of sickness. According to art critic Robert Hughes, Van Gogh's late works show an artist at the height of his ability, completely in control and "longing for concision and grace".
The most comprehensive primary source for the understanding of Van Gogh as an artist is the collection of letters which were passed between him and his younger brother, the art dealer Theo van Gogh. They lay the foundation for most of what is known about the thoughts and beliefs of the artist. Theo continually provided his brother with both financial and emotional support.
Their lifelong friendship, and most of what is known of Van Gogh's thoughts and theories of art, is recorded in the hundreds of letters they exchanged from August 1872 until 1890. Most were written by Vincent to Theo beginning in the summer of 1872. More than 600 letters from Vincent to Theo and 40 from Theo to Vincent survive today and although many are undated, art historians have been able to largely arrange the correspondences chronologically. Problems remain—mainly from dating those from the Arles period. Yet during that period alone, it is known that Van Gogh wrote 200 letters to friends in Dutch, French and English. The period when Vincent lived in Paris is the most difficult for art historians to examine because he and Theo shared accommodation and thus had no need to correspond, leaving little or no historical record of the time.