The skull at top center and dark colors lend a funereal aura to this portrait.
From Wikimedia.
Albertina Agnes’ dress has a natural waistline rather than the vee, although the puffed sleeves are de rigueur. The skirt appears to be attached to the bodice under a waist band.
Keywords: 1655, Mytens - Johannes, Albertine Agnes van Nassau, Princes van Oranje, Oranje-Nassau family, Princess, Dutch, proto-hurluberlu coiffure, fitted bodice, chemise, modesty piece, scoop neckline, bertha, brooch, elbow length puffed under-sleeves, contrasting turned back cuffs, clasps, fitted bodiice, waist band, natural waistline, full skirt