Photometrics is the science of the measurement of light, in terms of its perceived brightness to the human eye. In common usage photometrics is used to describe how lighting instruments are defined with regard to their sizes, light output, and uses. As shown in the picture above photometrics is best described as to how the angle of light will hit a certain something whether it is an actor or a prop. There is a lot of science that actually goes behind photometrics, which in turn helps with hanging lights with how someone should hang the lights to hit the stage.
Loading and Moving:
Loading and moving is a very important part of a theatre production and the theatre itself. When a play is on tour it can move from theatre to theatre and not every theater had what the production needs. Also, the productions can use something specific item that most theatres don’t have. Another reason is just the props themselves the production will already have the stage they want, the scenery they want, the specific props (such as a couch or lamp) they need for their production. Loading and moving is very important to a touring production because it transports all the productions essentials from theatre to theatre
Dimmers & Lighting Control:
Dimmers are devices used to vary the brightness of a light. By decreasing or increasing the RMS voltage and, hence, the mean power to the lamp, it is possible to vary the intensity of the light output. There are five different types of dimmers. These five are Rheostat dimmer, Saltwater dimmer, Coil-rotation dimmer, Autotransformer dimmer, and Thyristor dimmer. Dimmers based on rheostats were inefficient since they would dissipate a significant portion of the power rating of the load as heat. Salt water dimmers required regular addition of water and maintenance due to corrosion; exposed parts were energized during operation, presenting a shock hazard. The coil-rotation transformer used a fixed-position electromagnet coil in conjunction with a variable-position coil to vary the voltage in the line by varying the alignment of the two coils. Rotated 90 degrees apart, two equal affects the secondary coil but opposite fields from the primary, which effectively cancel each other out and produce no voltage in the secondary. Variable autotransformers were then introduced. While they were still nearly as large as rheostat dimmers, they were relatively efficient devices. Their voltage output, and so their dimming effect was independent of the load applied so it was far easier to design the lighting that would be attached to each autotransformer channel. Thyristor dimmers were introduced to solve some of these problems. Thyristor dimmers switch on at an adjustable time (phase angle) after the start of each alternating current half-cycle, thereby altering the voltage waveform applied to lamps and so changing its RMS effective value. Because they switch instead of absorbing part of the voltage supplied, there is very little wasted power. Dimming can be almost instantaneous and is easily controlled by remote electronics.
Reading Plan is probably the hardest subject I have tried to learn. The reasons being is I have always had a hard time converting the measurements on the plans to actual size measurements. Just the other day in class our teacher had pulled out plans that someone had created with a computer-drafting program. It was for the play “The Merchant of Venice” and the lesson for that day was to read the plans created and covert them. When our teacher asked for people to volunteer to convert the graph to actual scale I hid in the back to watch. However, after watching a few people covert the numbers I had started to understand how to convert the numbers on the plans with a ruler. Not going to lie I have always struggled with conversion and I felt very proud of myself for understanding this concept.
Rigging is an entertainment business term with a variety of meanings. The oldest type of rigging system out there is known as the hemp system. Merchant sailors developed the hemp system in the mid-nineteenth century. The rigging system was used originally for boats to help raise the mast and more. The system got its name from hemp rope that the merchants used. For todays theatrical use the rigging is tied to a batten or pipe or onto the grid. They use the rigging system mainly for curtains, drapes and scenery.
Hanging a lighting instrument is an essential part of preparing for a show. After the light is hung, it can be focused and added to the lighting panel for use throughout the show. Failure to properly and securely hang the light can be disastrous to a show as well as dangerous for performers and crew. To hang a light first you place the ladder under the grid so that climbing the ladder will allow you to reach the bar you wish to hang the light on. Ensure the light is in good condition and has a safety wire. Then carefully climb the ladder with the light. Attach the light’s C-clamp to the grid and tighten until secure by turning the bolt clockwise. Once the light is stable, attach the safety wire to the grid by unlocking it, fitting it around the grid bar and locking it. Use the wrench to firmly lock the bolt and light into place. After Plug in the light by plugging the light cable into a cable in the lighting plot. To further secure the connection, one can tape the plugs together with Gaft (or gaffer’s) tape.
Power circuits are used too apply Ac current to device throughout a theatre. Often the words line voltage or main are used to describe the supply of 120 VAC power. Most theatre installations use a 240v service, which the three conductors make up the system. A Three-phase power is the most common type of polyphase circuit. In a large , permanent theatre installation, the feeder cable to the dimmer racks is most likely in a conduit that runs directly into the dimmer racks and does not need to be changed from show to show.
There are three different types of electricity lighting, battery, and induction. Lighting is when atoms moving past each other in clouds form a negative charge, which jumps to the positively charged earth. Lighting has a huge voltage pressure, much larger than anything man-made. It needs a large amount of pressure to jump so far across an open gap with no conductor. Battery is when chemicals react with one another causing electrons to gather at the negative terminal, by drawing them from the positive terminal, when a conductive material connects the two terminals. Induction is a coil of wire spun in the presence of a magnetic field creates a voltage pressure, but rather than flowing in one direction like lighting or a battery, the electrons EBB and flow on a schedule determined by the speed of the generator.
A theatrical cue is the trigger for an action to be carried out at a specific time. It is generally associated with theatre and the film industry. They can be necessary for a lighting change or effect, a sound effect, or some sort of stage or set movement/change. The stage manager as a verbal signal generally gives cues over the headset system or backstage intercom, by a signal with a ‘cue light’ or by a show control system. There are 3 types of cues given Warning, Standby, and Go. Warning: Given about a minute prior to the cue and gives time for crewmembers to get ready and make sure everything is set. Standby: Given a few second before the cue and tell the crewmembers everything should be set and they should be standing by to go. Go: Given at the moment the cue should be executed. This sets the crewmembers in action.
The Proscenium is the defining element of proscenium theatre, basically a big picture frame dividing acting space from audience. All directions defined according to this division of the space by proscenium. Stage directions are given from the viewpoint of an actor center stage facing the audience. Stage Left is the actors left, Stage Right to the actor’s right. Downstage is towards the audience, Upstage is towards the back wall of the stage. The Plaster Line is a line running from the back of one side of the proscenium arch to the other proscenium. The Center Line runs upstage/downstage half way between prosceniums and perpendicular to the Plaster Line. Everything downstage of the Plaster line is called Front of House. Wings are the sides of the stage, and the Fly Loft or Scene House is the space above the stage. The floor is called the Deck. The part of the stage in from of the Proscenium is the Apron, or sometimes the Thrust. The Audience seating is the Auditorium or the House.