What are the duties of a designer in theatre?

Answer 1

A designer creates the world of the play. I like to think I design acting machines that give actors a world that has relationships built into it or at least the potential for relationships between the characters and the audience.

Answer 2

There are many types of designers:

Lighting Designers - make lighting cues, angle lights, upkeep lights.

Costume Designers - Design and create costumes.

Set/ Scenic Designers - Create background for the show

Prop Designer - create props for actors

Sound Design, Hair Design, etc. The list goes on.