Beautiful but strangely disturbing painting

The Children of Edward Darley Boit by John Singer Sargent

Painted in 1882

The four Daughters of Edward Darley Boit are, from left to right: Mary Louisa (1874-1945, about 8 years old at the time), Flourennce (1868-1919, about 14 yrs old), Jane (1870-1955, about 12 yrs old), and Julia (1878-1969, about 4 yrs old).

I first saw this painting at the Museum of Fine Arts in Boston eight years ago and it made a strong impression on me. I love the luminescent surfaces of the vases and the brooding shadows. I'm mystified by the strange isolation of the girls from one another and the sense of melancholy that pervades the painting. It's been in my mind today.