Barndoors & Gobos
Barn doors are hinged black metal flaps that attach or mount on the front of a light. They are usually a set of four or five doors that can be used to cut the light in a particular direction and are often used for keeping the light off of a background.
Barn doors are basically a type of gobo. A gobo is any object that is placed between the subject and the light and blocks some or all of the light. Barn doors are designed for use with spotlights and floodlights and are good devices for controlling spill light. Barn doors are available in different sizes, shapes, brands and styles. They generally range in price from about $5 to $50. They can also be bought in various light kits.