From the-athenaeum; spots removed from throughout image, but mainly from the darker parts with Photoshop and image made lighter by gogm.
Katharina von Henckel wears a large hat characteristic of the 1900s tilted sideways. She either wears a fichu or a garment (blouse?) with a wide collar.
Keywords: von Lenbach, Katharina von Henckel, Princess, German, curly coiffure, hat, high neckline, collar, necklace, earrings, wrap, fur