From Princeton University Art Museum :
The subject of the ballet became the dominant theme of Degas’s pastels in the 1890s. In these heavily textured, nearly abstract works, the artist stripped his scenes of any anecdotal content to concentrate on the movement and graceful arabesques executed by the dancers. With alternating layers of chalk and liquid fixative, the artist worked the pastel into the still-damp surface; his technique suggested that the dancers were slowly dissolving and reappearing in a shimmering array of color. Degas himself designed the frame for this pastel.