From a-l-ancien-regime.tumblr.com/post/14455324386/alexander-roslin-portrait-of-a-french-lady-called; left and top edges fixed along their entire lengths with Photoshop.
This may not be a titled Lady based on the absence of jewelry and lace in her neckline ruffles. Her coiffure and feathered hat are spectacular.
Keywords: 1780, Roslin, French, high straight coiffure, feathered hat, square neckline, chemise, modesty piece, ruffles, bows, tight sleeves