The Stage : Lighting
Lighting has always played an important part in creating stage atmosphere. You see the effects on the stage but you won't necessarily appreciate the number of lights or diversity of the electronic systems used to control them.
This photograph shows part of a screen used for back projection of video images.
Some lights design principles
Stage light design is based on an electric light with a reflector placed behind the lamp to direct the light forwards, Spotlights use a lens to focus the light. Filters and patterns (gobos) can be placed in the path of the light beam to give colour or to project a pattern.
Flood lights are used to spread light evenly for general lighting.
Spot lights use a lens to give a focused beam and can be used to project patterns. The patterns are usually cut in thin aluminium or steel sheets and are called 'gobos'.
They sometimes have metal plates attached to the front to control the pattern
Motors can be used to change either filter colours or projected patterns The photograph shows a light with a front mounted sheet winder. Different colour acetate filters are joined end to end (like loo paper) and can be wound from one roller to another. The light shown here is called a 'Rainbow box' and you can see two different colours on the sheet winder.
Filters and patterns can be mounted inside the lamp casing. Glass filters commonly use a thin film layer of colour, which has been evaporated onto the glass. These are called dichroic filters. You can just make out the coloured filters in this picture. Here you will also see a stepper motor driving these filters around.
Stepper motors are used to rotate the disc sections into the path of the light beam. Stepper motors are used because the filters and patterns can be accurately positioned.
The lights used in a modern theatre are very sophisticated. Many lights are fixed in place and simply hang from a gantry either above or in front of a stage. Some lights, however, can be remotely controlled to point in any direction and show a variety of colours and patterns as mentioned above.
The Martin Mac 500 is one example of a light which allows the beam direction and a range of colour and pattern effects to be controlled remotely. When switched on it automatically moves to its home position in order to establish a reference point for network instructions.
The Martin Mac 500 shown here is sitting on the stage floor ready to shine light a swivelling light upwards all over the stage area.The Claypaky light is a different example of a remote control moving beam lamp.
This design uses a mirror which ran be rotated in three directions. The low mass of the moving parts enables this system to provide rapid beam movements.