Lady Johanna died before her husband and son, so I am unsure about the occasion for wearing such somber dress.
From lydiardhouse.blogspot.com-2011-12-lady-st-johns-of-lydiard-johanna-st; spots were removed throughout the image with Photoshop and the image was made lighter by gogm.
Aging Lady Johanna wraps her head in a hood that covers the upper portion of her dark over-bodice in this portrait.
Keywords: 1655, Wright - John Michael, Johanna St John, St John family, curly coiffure, hood, bows, high enclosing neckline, over-bodice, full cap sleeves, quarter length full notched over-sleeves, puffed under-sleeves