sargent's brush strokes are clearly influenced by the impressionist movement here, their shape becomes more irregular & free formed. I just love the vivacity in this woman's face. the motion in her pose. the whole painting is just full of life. the space surrounding her eyes is stunning, the shades of peach, pink, & red in her skin makes you feel her blood flowing. she's radiant.
she's also sargent's sister. which I think explains her lively air & tenacious pose.
it also helps that her pink dress is fabulous.