Theatre lanterns. Mechanical element (yoke, casing, accessories slots/ holders) Thermal element (vents, louvres, fans, heatsinks)

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1 Theatre lanterns Thermal element (vents, louvres, fans, heatsinks) Mechanical element (yoke, casing, accessories slots/ holders) Elect rical supply (plug and cable), lamp base, lamp Optical elements (lenses and reflectors)

2 Types of generic lanterns: Floodlights: The most basic theatre light. It usually comprises of a linear lamp with a reflector behind it with the aim to spread light evenly over a large area. The shape of the reflector determines the distribution of light. In the cyclorama floodlight (cyc flood) an asymmetrical reflector is used to achieve an even spread of light while the flood is rigged fairly near the cyclorama, either at the top or as a groundrow at the bottom. The chassis usually has a slot for a colour frame to allow a good distance between the lamp and the colour gel to avoid it burning out too quickly. PARs: Often referred to as PAR cans due to their simple built (a metal can with a Parabolic Aluminised Reflector lamp fitted in it). Different sizes are referred to by numbers, with the PAR64 the most commonly used size. Each size is available in a long nose and a short nose version. The beam angle is determined by the choice of lamp and is a fixed oval beam. The light output of a PAR can is generally very punchy, which makes them especially suited for strong colours. Before moving lights the PAR can was the single most commonly used lantern in Rock n Roll lighting.

3 The most commonly used lamp types for a PAR 64 are : CP60 : very narrow spot (clear lens), 9º x 12º, 1000W CP61: narrow spot (stippled lens), 10º x 14º, 1000W CP62: medium flood (pebbled lens), 11º x 24º, 1000W Other commonly found sizes are the PAR56 (often fitted with 300W lamps) and the PAR16, or birdy. The latter retains the shape of the PAR can but uses an MR16 lamp. Beware that the wider lamps can often have their beam cut off by the length of the nose of the can itself. An overview of different PAR lamps: Name 1000W 500W Beam angle Very Narrow SPot CP60 CP86 9º x 12º Narrow SPot CP61 CP87 10º x 14º Medium FLood CP62 CP88 11º x 24º Wide FLood EXG 57º x 21º EXtra Wide FLood CP95 70º The Source 4 PAR is an attempt by manufacturer ETC to create a more energy efficient and physically smaller version of the PAR can. S4 PARs use a HPL tungsten halogen lamp of either 575W or 750W. The great benefit of the S4 PAR is that it is possible to change the lens to alter the beam angle. Lenses available are Very Narrow Spot (VNSP, clear lens), Narrow Spot (NSP, stippled lens), Medium Flood (MFL, 8 rows of pebbles), Wide Flood (WFL, 12 rows of pebbles). Also available as a nonstandard addition is an extra wide lens. There is also a discharge lamp version of the S4 PAR available, but rarely used in theatre due to it not being dimmable. An overview of Source Four PAR lenses: Name Acronym Beam angle Appearance Very Narrow SPot VNSP 15º Clear Narrow SPot NSP 19º St ippled Medium FLood MFL 21º x 34º 8 rows of facets Wide FLood WFL 30º x 51º 12 rows of facets EXtra Wide FLood XWFL 60º Lots of small facets

4 PC (pebble/prism convex or plano convex): A washlight with a soft edged beam. By moving the lamp in relation to the fixed lens the beam size can be changed significantly. The edge of the beam can be shaped using barndoors, but will always remain soft. Plano convex lenses give a harder edge than a pebble convex lens. Fresnels: Named after the inventor of its lens, Augustin-Jean Fresnel ( ), Fresnel lanterns are one of the most common wash lights in use in theatre in the UK today. Originally the lens was an answer to the problem of large lighthouse lenses. Using a number of stepped concentric rings of lenses made it possible to achieve a similar focus to the PC lens while using a much smaller amount of glass. Fresnels are generally a little softer than PCs with more flare due to the refraction of light in the steps of the lens. The edge of the beam can be shaped using barndoors, but will always remain soft. Outwardly Fresnels and PCs are very similar looking, often manufacturers use the same housing for both, so make sure you don t get them mixed up during rigging.

5 Profiles: Profiles are able to project clearly defined sharp beams of light. There are two basic kinds, the fixed beam profile and the zoom profile. A fixed beam profile has only one lens. By moving the lens in relation to the fixed reflector and lamp the beam can be sharpened or softened. The size of the beam can only be altered with the use of an iris. Zoom profiles have two lenses. By moving the lenses in relation to each other and the fixed reflector and lamp the size of the beam can be adjusted as well as the sharpness. Profiles generally have four shutter blades to shape the beam and a slot for holding gobos (thin metal or glass plates with images that can be projected) and/or irises. The whole lens barrel can normally be rotated to allow alignment of the shutters. Other accessories commonly used with profiles are top hats and doughnuts. Top hats are fitted into the colour frame slot and are designed to reduce flare, especially when rigging profiles in front of house positions. Doughnuts are also inserted in the colour frame slot. They are essentially just a circular mask that can help sharpen the projection of a gobo.

6 Changing a lamp Most generic theatre lanterns use tungsten halogen lamps. When changing a lamp, make sure you do not touch the glass portion of the lamp. Even clean hands leave small amounts of grease, ie fingerprints. These bits of grease cause a hotspot on the glass and shorten the lamp life. Always let the lantern cool down before attempting to change the lamp. You can also use appropriate heat proof gloves if need be. Make sure you disconnect the power before opening the lantern. Just taking the light to zero on the lighting desk is not enough. Some theatre lamps have two different sized pins. If a lamp doesn t seem to fit properly, don t try to force it. Try it the other way around. Rigging: IWB: G-clamp:

7 Stands: bench stand lighting stand spigot boom arm outrig arm

8 Intelligent Fixtures All generic fixtures only have the one parameter that is controlled from the lighting desk, the intensity. Intelligent fixtures let you control more than one parameter, for example pan and tilt for moving heads, or colour mixing for basic LED fixtures. Firstly, conventional moving lights (as opposed to LED fixtures). There are two main types, moving mirrors and moving heads. The first is rarely used anymore in theatrical lighting, you will still see them in clubs, but even there the moving head is taking over. The light and optical elements are fixed and the beam of light is diverted using a moving mirror. This restricts the areas they can reach quite a lot depending on where and how they are rigged. The moving head is the most common type of moving light currently being used. The whole light, including lamp and optics move on a rotating yoke. There are two main types of moving heads, wash lights and spots. The parameters available in each will vary considerably between types and manufacturers, always check the specifications. Normally a moving lights will have at least intensity, pan, tilt and some form of colour mixing. This can for example be a simple colour wheel or CMY colour mixing. It is important to be aware of the different lamp types moving lights use. For example our VL 1000 are tungsten spotlights, the TW1s are tungsten wash lights and the Robe Colourwash 575 AT has a metal halide lamp. The latter is called a discharge lamp and is not dimmable using normal dimmers. Instead it has a built in dimmer shutter to reduce the output of the lamp. This means that the lamp remains on even when the channel on the lighting desk is brought to zero, but the shutter in the lamp is closed. It s important to be aware of that, as it has an impact on heat generation and the use of electricity. Because the lamp is constantly on, moving lights with discharge lamp need constant cooling, which means there will be a certain amount of fan noise that is permanently present. Even though some fixtures offer studio or quiet modes in which the fans run at slower speeds to reduce the noise, these units are often unsuitable in smaller venues. Fixtures with tungsten lamps often have silent modes in which the fans only kick in should the unit reach a certain level of temperature. These fixtures are much more suitable for use in theatre. Moving lights with discharge or arc lamps also have a very different colour temperature, which makes blending them into a rig with conventional lighting very difficult.

9 Generally moving lights and LED fixtures cannot be plugged in to normal dimmer channels, they must be given a separate non-dim power supply. Even those with dimmable tungsten lamps often have an onboard electronic dimmer that means they will only require a nondim power supply. There is a lot of development in the world of LED moving lights. Most LED moving heads are wash lights, some with very good zoom functions. Beam shaping is still very limited, though I would expect/hope that to change very soon as LED optics develop further. We are currently seeing the first LED moving head profiles being released. LED moving heads offer some big advantages, as they are often considerably lighter than conventional moving heads and also require a lot less power. In colour they are more similar to discharge lamps and just like these unfortunately not quite as good at softer pastel colour tones as conventional tungsten lamps.