Reading a Light Plot
Most technician’s first encounter with lighting is when installing, or hanging, the lighting for a show. The light plot, like many of the technical drawings examined in chapter 5, is in scale. The light plot is full of symbols.
A Light Plot
The light plot looks similar to the ground plan, including the title block in the lower right-hand corner. The set is sometimes represented, but often it is not. Instead of accurately drafting all the lights, they are replaced by symbols. This is important as lights, though different, look the almost identical. Around each lighting symbol, you will see a series of numbers. Although there are some accepted standards, the symbols and the numbers will vary from designer to designer. Fortunately, lighting designers always include a key and a legend to explain what everything is. Most stage lighting positions are parallel to the stage floor. Some theatres also have lighting positions that are perpendicular to the stage floor, often called booms. Many light plots will express this image as a diagonal line, with the bottom of the position represented by the side that is closes to the center line. Many designers also include a dimensioned line so that people installing the light plot do not need to carry a scale ruler with them.
Key and Legend
At the top of the above illustration, you see the key. Each light symbol is shown, in scale, with an explanation of the type of light it is next to it. The designer in the above example, has included additional useful information. It shows how many of each type of light the theatre owns, how many the designer has used and how many are remaining in inventory. This list can greatly assist the electrics crew as they are moving lights from storage to the theatre.
Below the key is the legend. The legend details all the information around the light. Different designers will place the information in a different location, sometimes in circles or squares or rectangles.
- Focus indicates where the light hits the stage. The information can allow the electricians to pre-focus the light in vaguely the right direction.
- Color indicates what brand and catalog number of the color media which will tint the light from white to whatever color the designer desires.
- Gobo indicates the gobo, or metal template inserted into some lights to create a shadow pattern in the light.
- Unit number, is the only information that appears on all light plots. The unit number is unique to each instrument on a lighting position. This allows electricians and designers to specifically identify any light in case of problems or required adjustments.
- Channel number is the name that the programmer of the computer that controls the lighting system uses to turn on the light.
- Dimmer is the name of the device that illuminates the light. The industry is moving from the term “dimmer” to the term “address.” Dimmers are not much of a part of newer lighting systems as they once were. Address is a more generic term that refers to the way the light will be controlled system.
Load-in and Focus
The electrics crew, led by the master electrician, will examine the light plot to make sure they have all the color, gobos, lights, and power cable indicated by the light plot. They will get all the equipment together. On the day of the load-in, when the lights are installed in the theatre. It is important that the correct light is installed. It is important that the lights are placed correctly and pointed in the correct direction. The crew will work to power all the lights. It is important when running power cable that you run from the source of the power to the lighting instrument. This is because, in the event the light needs to move you want any spare cable near the light, not at the power source. After the lights are hung, all the color and gobos need to be installed. Once all the lights are plugged in, the master electrician will work with the board operator to patch the lights in the lighting control desk. Patching is the process of connecting the address that controls the fixture to its assigned channel number. After this process, it is important to do a dimmer check. Each channel will be turned on and checked that it is the correct light, with the correct color and the correct gobo.
Once everything is working, the designer will come into focus the show. Focus is a process where each light is turned on and under the direction of the lighting designer will point each light where it is supposed to be. Focus works best if each step of focus is done in the same order. The order is usually similar to this:
- Remove any color media from the light
- Set the focus to the format the is best for the light
- Point the light so the center of the beam is on the designer’s face. The designer will often make small adjustments until it is perfect
- Adjust the quality of the beam under the designer’s direction.
- Replace the color and gobos.
After that is done, move on to the next light. It is important the focus be efficient because there is rarely as much time as the designer and electrics team would like.
Lighting Break Down
The lighting breakdown indicates anything in the script that would suggest things about what the stage lighting would be like. In a play with continuous action and no set changes such as “Box and Cox”, the breakdown might be fairly simple.
Interior room, early morning
Lights Fire (effect)
By this point it is 10:00
Obviously more complicated plays will have considerably more. You will note that the play starts first thing in the morning, yet by the end it is about 10 am. The lighting designer will have to adjust the light coming through the window so that the time change indicated is accomplished.
The lighting designer, after watching rehearsals and working with the director will develop a list of every time the lighting changes in the production, and some idea what is to happen with each cue. A cue, in lighting terms, is where a lighting change happens, what changes and how long it takes for the change to occur. Each cue will be carefully planned as to where it happens in the script. With this plan, the designer will work with a programmer to record all the cues into the lighting desk. The lighting desk is a specialized computer that will control all the lights. Often a Stage Manager, or Assistant Stage Manager will be in the theatre with the designer and the programmer and a hand full of additional people. The additional people, under the direction of the Stage Manager, will stand on stage in the spots where the actors would normally stand. This allows the designer to see what the cues will look like on stage and make the technical rehearsals move faster.