Underpainting

Underpainting - student project

Underpainting - image 1 - student project

Worked it up to this point and have now let it dry, but I'm now concerned about the white curtain. I was thinking of trying to glaze some yellow-brown tint over it to darken it to up the contrast with the figure, but I don't want it to end up muddy and too brownish overall. Any advice?