The design for a scripted performance should take into account anything that the audience can see or hear. Design ideas need to enhance the performance and support the performers in engaging the audience throughout the play.
set designer - designs and organises the layout of the set and stage
costume designer - designs the outfits worn by all characters
lighting designer - designs the lighting used throughout the play, including lanternThe technical term for a stage light. and additional lighting that may be used on stage, eg lamps, torches or candles
sound designer - designs the music and sound effectThe artificial reproduction of sound. needed for the performance
Apart from sound, these aspects are collectively known as the visuals, as they are the elements that the audience can see. Although they are all planned by designers, during a performance it is actually the technicianThe people in theatre who operate technical equipment, eg a lighting desk. who operate the equipment, eg sound control panels or lighting desks.