A young woman, identified as Charlotte Barton of Boston, sits in a green patterned chair, adjusting her pearl-tipped hatpin in a gilded mirror. A corner of Vermeer’s The Music Lesson can be seen in the upper right corner. She is dressed very elegantly, and, as suggested by the title, is going out to the matinee. The loose brushstrokes of her shirt, hair, and hat are elegantly contrasted with the solidness of the chair she is sitting in.
source: Artsy, WikiCommons