Jacques-Emile Blanche, an admired portraitist in the 1880s, portrayed Proust as a young man, aged 21, when he was still only a social chronicler. Blanche was then developing a brilliant, rapid technique; but this portrait is highly restrained and particularly powerful.
The young dandy is presented in a front view, in a hieratic pose (the painting was probably originally a full-length portrait). The contrast between the very dark tones of his suit and the background and the flesh-colored face and collar, toning with the white orchid in his buttonhole, is particularly striking. The sharp outlines, the fluid paint, and the delicate strokes bring out a sense of inner feelings. Young Proust with his great dark eyes and sensual mouth is already a little more than a dandy: the perfect oval of his face and the pallor of his complexion give him a grave almost Christ like look. That probably explains why this portrait has remained the best-known and most accurate representation of the man who was not yet the author of Remembrance of Things Past. Proust kept this painting until he died in 1922.
(http://www.musee-orsay.fr/en/collections/works-in-focus/search/commentaire_id/portrait-de-marcel-proust-29.html?no_cache=1)