From thedreamstress.com/costume-portfolio/portfolio-a-1660s-dress-for-ninon-de-l’enclos.
This is a study in black and white, and a little blue. Both subjects wear full sleeves. The lady wears a chemise, barely visible. Her skirt has the typical mid-century somewhat full shape.
Keywords: 1660, van der Helst, Dutch, long curly coiffure, chemise, scoop neckline, split bodice, square neckline, bows, elbow length full sleeves, cuffs, waist band, vee waistline, close skirt, necklace, earrings