professorpski:

It’s the 1770s, summer hats are flat and tie on with ribbons, and hair is powdered white, so even a woman with a young face has the hair the color of a much older woman, and lush silk makes the dress. This painting by Francois Boucher hangs in the National Gallery in Washington, DC and I marveled at his ability to capture the lustre of silk. The color might be called silk white as opposed to paper white, that stark white which we are more used to, but so much harder to wear. Silk white is closer to ivory and allows her complexion and its pink undertones to glow as well. Notice also the corset which seems to squeeze her in at the sides rather than at the front, and the wide blue ribbons of silk which both trim her bodice and catch up the sleeves. With silk this heavy, the pleats and the gathers look especially luxurious and this was a time when showing off your wealth was at a premium.

You can find out more about it  and Bocher here: https://www.nga.gov/collection/art-object-page.32681.html