The Royal Academy will on Saturday open the first retrospective in the UK of works by George Bellows, an artist who never quite became the household name many believe he should be.
"It is an amazingly energetic and visceral painting. The composition is so powerful," said Dumas. "Flash forward and you think of Francis Bacon almost. He must have painted it quite quickly because it has so much gusto and the way that the paint is applied, you think the brush can hardly have left the canvas."
He is also known for his social conscience, and the show includes lithographs he did for leftwing publications and a small room of paintings showing German atrocities in the first world war.
Dumas said Bellows was a macho guy and a kind of a tough "all-American" painter. But "I hope this exhibition shows that he's more complex than that, he's more layered and he knew a great deal about European Old Master painting."