Stage decorations and backdrops perform several functions during a show. They are responsible for setting the mood of the show and create a visual world for the play. The set of a play helps to fulfill a director's or playwright's vision for the production.
The set and backdrop can also determine the way in which actors move about the stage. For instance, the set may consist of elevated platforms that the actors can climb upon or benches and seats for them to sit on. A wall set on stage can give actors a place to hide behind. Realistic props can increase the verisimilitude of a production.
Stage backdrops are usually made from muslin and are either painted on or digitally printed. The backdrops are designed to be hung from a rail. Stage flats are usually made of a wood frame with plywood on top or muslin stretched across the frame. Scenic artists usually use tempera paint on flats and backdrops.