When your teacher tells you to cut the light at a certain point he wants you to use the shutters to cut the light off at a certain point. You adjust the shutters by pulling them out or pushing them in.
When focusing a light there are certain terms you must know so that when somebody asks you to focus a light when your up on a ladder, you know what you are doing.
When your teacher asks you to flag the light it means to swing your hand back and forth in front of the light. You are asked to do this so that your teacher can see where the light spot is.
When your teacher asks you to run the barrel he wants you to loosen the hand screw on the lamp housing and to pull down the barrel until he tells you to lock it.
