Matisse likely began work on the third state of Bathers by a River in the spring of 1913. As he transformed the formerly idyllic, pastel-colored scene, the artist used a more exaggerated approach to modeling. He changed the once-graceful stance of the left figure, for example, into a more rigid, upright one by blocking out the volume of earlier limbs and musculature with wedge-shaped forms, much like the carving he used to change his bas-relief Back. While he generally worked within the existing palette, he executed his most dramatic revisions to the forms in the new colors of pale pink, dark gray, and black.
The exaggerated modeling that Matisse utilized in Bathers by a River recalls the dramatic effect of highlights and shadows that he witnessed in Morocco and recorded in a number of drawings and paintings from his travels. In this case, the heavy brushwork he used to model the bodies of the bathers echoes the hatched shading he employed for the right figure of the Moroccan-period sheet Backs and Scene of Tangier.
On May 13, through the introduction of Gertrude Stein, the American photographer Alvin Langdon Coburn visited Matisse in his studio, where he made a number of portraits of the artist for his forthcoming publication Men of Mark. The majority of these images present Matisse armed with a large palette and brushes, standing on a ladder while working on Bathers by a River. Photographs also record the canvas, which was clearly in a state of transition.