What are the main features of the proscenium arch?

The proscenium arch is a key architectural element in theaters, framing the stage and separating it from the audience. Its main features include a large, rectangular opening that enhances sightlines and creates a defined stage area, often decorated with elaborate designs. The proscenium arch also helps to control acoustics and lighting, providing a focused environment for performances. Additionally, it often serves as a backdrop for stage sets and can be used to enhance the visual storytelling of a production.