The role of the lighting designer (or LD) within theatre is to work with the theatre director and set designer to create an overall 'look' for the show in response to the text, but bearing in mind issues of visibility, safety and cost.
The LD is usually an outside freelance specialist hired early in the production process, but there are many theatre companies whose lighting chief is also responsible for most or all of the lighting designs. The LD will read the script carefully and make notes on changes in place and time between scenes - such changes are often done just with lighting - and will have meetings with the Director, Designer and production manager during the pre-production period to discuss ideas for the show and establish budget and scheduling details. The LD will also attend several, late, rehersals to observe the way the actors using the stage area (or 'blocking') during different scenes, and will receive updates from the stage manager on any changes that occur. The LD will also make sure that he or she has an accurate plan of the theatre's lighting positions and a list of their equipment.
All this information is vital for the preparation of an accurate lighting plan and lighting plot.
The plan is a scale drawing of the theatre's stage and auditorium lighting positions with the show's lanterns marked on it. Next to each lantern will be information for any gel, gobo, animation wheel or other accessory that needs to go with it, and it's channel number. Professional LDs usually use special computer aided design packages to create accurate and easily read plans that can be swiftly updated as necessary. The LD will discuss the plan with the show's production manager and the theatre's lighting chief to make sure there are no unforseen problems with the plan before the latter places a hire order for any specified extra equipment.
The lighting plot is a list of the lighting states that the LD intends to use for each scene during the show. Ideally, a pre-production lighting plot will have levels specified for every lantern and up and down times for each lighting state, or cue, but it is accepted that there will usually be many changes during the technical rehersal of the show.
During Fit-up and Technical Rehersals
The LD is responsible, in conjunction with the theatre's lighting chief, for directing the theatre's lighting crew in the realisation of his or her designs during the technical rehersals. The LD usually sits at a temporary desk somewhere in the auditorium where they have a good view of the stage and talks to the lighting board operator/programmer over a headset. The LD will direct the focusing (pointing, shaping and sizing of the light beams)and gelling of each lantern before recording a version of the lighting plot. At an arranged time the actors arrive and the play is worked through in chronological order, with occasional stops to correct sound, lighting, entrances etc. The LD will work constantly with the board operator to refine the lighting states as the technical rehersal continues, and will avoid stopping the rehersal to make corrections if at all possible. Any errors of focusing or changes to the lighting plan are only corrected once the actors take a break.
Once the show is open to the public the LD will stay and watch several performances of the show, making notes each night and making desired changes the next day.