The Portrait of a Lady in Blue, or Woman in Blue, is an oil-on-canvas portrait by English artist Thomas Gainsborough, from c. 1775-1785. It is held in the Hermitage Museum, in Saint Petersburg, to which it was left in 1916 by Alexei Khitrovo, making it Gainsborough's only work in Russia. Thomas Gainsborough, 1780 — painted at 53. Canvas and oil paint. 76.5 × 63.5 cm. In the Hermitage Museum. Wiki link