The facebook page for WB’s Harry Potter Studio Tour has released this picture of the Great Hall set as it was for the filming of the Yule Ball in Goblet of Fire. They also revealed some of the techniques that went into giving it that cold, wintry feel.
“Here are some of the tricks the film-makers used: the Studio lights have blue lighting gel on them to create a chilling effect; the Great Hall walls were covered in a special silver treatment; the flambos were painted gold; silver curtains hang from the walls, and if you look really closely, the flambos have been changed to a reflective material and there is “ice” inside them (made from clear-cast resin). Get ready to step into the Great Hall in 2012!”