Two new drawings by Edgar Degas confirm the collector's admiration for the artist's early works, having purchased a considerable number (at least 81) from the four public sales of the artist's studio collection following his death in 1917. The same applies to Camille Pissarro's work—with a drawing and a very rare monotype—of which Senn purchased pieces as early as 1900, and later in 1931 seven drawings at a public auction. Two colourful pastels by Armand Guillaumin have also been added to the beautiful set donated by Hélène Senn-Foulds. They were likely purchased directly from the artist, with whom the collector was on friendly terms.

A knowledgeable collector of paintings, Olivier Senn was also an avid collector of drawings. With intelligence and sensitivity, he compiled a coherent and highly personal collection, carefully choosing major pieces by a few artists he appreciated especially, such as Degas, Cross, Boudin, Guillaumin and Marquet.