Cinematography in "Black Narcissus"

Okay, the first thing that jumped out at me watching Black Narcissus was the cinematography used to portray the character, Sister Ruth. For those who have seen the movie already know what I am about to say. The cinematographers style for portraying Sister Ruth is incredible. You see Sister Ruth transform from the white, pure nun to the dark, haggard, psychopathic killer toward the end, mostly aided by the use of cinematography. For example, the scene where Sister Clodagh and Sister Ruth have a serious conversation about leaving the convent. Sister Clodagh, notably in her white robes, is placed in front of the window with sun shining through so bright, that it occasionally over-exposing the camera. This probably represents her true purity. However, Sister Ruth is placed in front of a smaller window with the light beginning to fade in the dark room, representing her movement away from the convent community. As her metamorphosis goes on, she is repeatedly put in dark places, with dark clothing, decorated with evil, sometimes scary looking makeup, all of which use the skill of cinematography to its fullest manipulation. Not a bad movie for a bunch of nuns....