This is a portrait of the painter's sister, Thérèse de Gas (1840-1912), of whom the artist was very fond. It was probably painted just before Thérèse married her cousin Edmondo Morbilli, the son of a noble Neapolitan family.
The figure of Thérèse forms a perfect triangle, with her wide dress forming the base, giving her an astonishing solidity and presence for her young age. Rivalling Ingres, Degas depicts the elegant costume in minute detail. Within this harmony of greys, whites and blacks, whose depth is the equal of Manet, the long, pink satin ribbons, tied under her chin, provide a bright, cheerful note.
In the background, a window opens on to a view of Naples, although the portrait was painted in Paris. The appearance of the town, where the young woman would go to live after her marriage, is a clue to deciphering the painting. The same applies to her hand coming out from under her shawl, revealing her engagement ring.
The portrait, classical in its composition and its lighting, and almost like a society portrait in the rigidity of the model, is infused with great psychological subtlety. Thérèse's expression is both subdued and faintly questioning. Very subtly, Degas translates the internal tension affecting his sister as she prepares to get married. The contrast between the darkness of the empty interior, announcing the departure, and the light of the countryside, symbol of an optimistic future, expresses ambivalent feelings. This duality is also heightened by the two painting techniques used together here. The hand with the ring is painted with great care, whereas her other one, barely defined, seems to lack consistency. This alliance of a dry precise technique with a very modern, casual style gives the portrait an unusual charm, making it a wonderful piece of painting.