First masterpiece: The potato eaters

The potato eaters 

Van Gogh hoped that a large work featuring several people would help prove himself to the outside world. Paintings of peasants having their daily meal were popular at that time. He practiced for months painting heads, and many studies preceded the Potato Eaters. He was satisfied with the result but his brother Theo and his artist friend Anthon van Rappard were very critical of his work. 

In reality, every day in the gloomy cottages I see effects against the light or in the evenings in the dusk that are so curious that so far my work still seems to me too light for the effects in question

Letter 506, Vincent Van Gogh to Theo van Gogh