In Mary Sheriff's opinion, what is the subject of Elisabeth Vigee-Lebrun's painting Self Portrait 1790 ?

As the art historian Mary Sherrif proposes, the subject of Elisabeth Vigee-Lebrun's Self Portrait 1790 is undeniably the artist herself, and the art of painting. In this composition her face lit by bounced light Vigee-LeBrun looks towards the spectator, she is seated upright, posed and poised very much in an aristocratic manner in front of her canvas. She holds a paint brush in one hand, and a palette and collection of brushes in the other sketching …

…the difference between drawing and memory. From the composition it appears that the portrait of Marie-Antionette is gazing directly upon the artist as though the sitter is apparent outside the boundaries of the frame. Yet the self portrait was executed subsequent to Vigee-Lebrun's exile to Italy; as a result she is depicting the image of Queen Marie-Antionette purely from memory, at a time when women artists were not thought capable of such inventive artistic endeavors