1817 Elizabeth Alexeievna by Peter Ernst Rockstuhl (State Tretyakov Gallery)
From Wikipedia; image lightened to bring out detail.
Elizabeth wears a black ensemble - hat and feayhers and dress broken up by a white partlet in this Peter Ernst Rockstuhl portrait.
Keywords: 1817, Rockstuhl - Peter, Elizabeth Alexeievna, Princess, Tsaritsa, Baden family, Romanov family, Russian, feathered hat, strap, scoop neckline, partlet, sweetheart décolletage, long upper puffed sleeves, Empire waistline