He was a regular contributor to the Impressionistes et Symbolistes , and a founding committee member of the Salon d'Automne. Dethomas is also remembered for his close friendship with the artist Henri de Toulouse-Lautrec , his brother in-law Ignacio Zuloaga and his association with Les Nabis and other important Post-Impressionist and Symbolist artists and writers. Dethomas died in at the age of 61, and was buried at the Passy Cemetery , Paris.
His family came from a long line of painter-printers on one side, and lawyers on the other. His father, Jean-Albert Dethomas — , was an important Parisian politician and lawyer. During , Dethomas first met Augustine Bulteau — , matriarch of the Parisian arts community and one-time wife of prominent author and playwright, Jules Ricard — Bulteau would go on to become a pivotal figure in his life, helping him navigate a difficult relationship with his father, guiding his academic direction and encouraging his development as an artist.
The things I see by him always give me an intense desire to work. The things of this boy, who, if he has no talent, certainly has a little genius, are always for me a whiplash [coup de fouet]. It's as if I was shown the way with a sudden invitation to advance. The master paintings do not give me that, we are stupefied with admiration. We are blocked, discouraged, after them we are let down, we are in prison.
During this period, Dethomas became firm friends with fellow Gervex student and future brother-in-law, Ignacio Zuloaga. He realised vigorous drawings, and some few oil paintings, showing portraits, cafe scenes, and urban landscapes of Italy and Spain.
Like many of his contemporaries, Dethomas explored various artistic mediums, including book illustrations, posters and print making. He was tall and stout, with a pallid complexion, the type of slightly fleshy giant who spent his nights making sketches in night clubs. He had great difficulty staying awake after meals, which for him always had to be enormous.
