This particular clip shows various lighting techniques. From the audiences perspective the only light source seems to be coming from the single window above in Andy Dufrenes cell.
The light is very harsh through the window and creates a very hard back light on the warden. This lighting as I mentioned before in my other posts is commonly used in horror and crime films, as it can be a rather intense and dramatic view on the character.
The wardens character himself is considered hard and tough so this lighting fits perfectly in his characters. When we look at the lighting positioned to the other characters it is very bright and well lit with a slight shadow from the corner. This lighting can create a sense of vulnerability as each of the officers are conflicted and are unsure of the problem.