It appears to be dark outside this elegant room: a blue curtain covers the top part of the window, but the glass below it is black. The light which glints in the heavily dilated pupils of the woman seated at the keyboard comes from in front of the painting, an unusual effect for Vermeer. Significantly, the picture hanging on the wall shows a prostitute flirting with a client. Vermeer tended to hedge them with uncertainties, but here the background picture gives an unusually strong hint, which encourages us to wonder if the keyboard player has more than music on her mind. This painting is now located in The National Gallery in London.