Together, in 1909-1910 they participated in the activities of the Société Normande de Peinture Moderne, an artists' group based in Rouen. By the spring of 1912, when Suzanne [fig.
1] prepared to send several of her paintings for exhibition to the Salon des Indépendants, she avidly sought the advice of her older, more experienced brother.
Despite this acclaim, he chose to abandon the lucrative career of a painter whose fame would have virtually guaranteed success.
Instead, he elected to work quietly on the and various related projects and occasionally issued a Readymade sculpture.
Ever since his arrival in New York, Duchamp had been the star attraction at the many gatherings held at the Arensberg apartment, which by 1917 had developed into a virtual haven for progressive European and American artists. Here artists from both sides of the Atlantic were given ample opportunity to compare their work—examples of which hung side by side on the walls of the Arensberg apartment—and they were also provided with a congenial atmosphere in which to exchange ideas and opinions concerning the exhibition and promotion of the new art in America.
You seem to be interested in the color harmonies for their own sake, for the relationship (in your portrait, for example) between the background blue and the stripes of the blouse, and not for creating atmosphere: in that respect I agree with you.
But I think that the relation of color to color, since it's only optical, expresses the artist less than drawing (see the Impressionists), and as it so happens you draw, unconsciously perhaps, before anything else.
There is no plastic difference between drawing on paper and painting on canvas.
The latter consists of drawing made with colors which are the different tones of your harmony in black and white (even though they are colors). The emphasis Duchamp places on the importance of line over the optical properties of color is partly a reflection of the Cubists' preoccupation with a monochromatic palette.