High Key - What Is It?

Assignment for Advanced Portraiture this week is to shoot either high key or low key.  I have chosen high key and my model is one of my classmates, Katie Dehlinger.  I am hoping to do something simple and elegant, but especially want to bring out her bright blue eyes.  The key to making sure you have a high key photograph is the way you light the background.  Here is one sample of high key photography.