LX Guide: Intellegent Fixtures

'Intelligent' fixtures (or 'intels') or 'dynamics' are a (relatively) recent development in the world of theatre luminaries. Their name is really a misnomer – they do not really show any intelligence – they really only differ from standard/traditional lanterns by their ability to change their focus or beam characteristics remotely. The exact means by which this happens varies, depends on lantern type.

They can offer a number of advantages:

  • Remote focusing, – fixtures may be adjusted mid show, or in inaccessible positions
  • Flashy effects – moving, changing beam shapes, colours, etc
  • Can replace multiple 'specials' i.e. one intelligent can perform multiple roles

Though spectacular effects may be achieved, on the downside, dynamic fixtures tend to be expensive, heavy, take a long time to program and can be unreliable and noisy.

Capabilities vary, but motorised features may cover:

  • position,
  • brightness,
  • shutter (for dimming and strobing),
  • colour wheel (to select one of a set of filters) or full colour mixing (allowing any colours to be mixed from the primaries),
  • selection from multiple gobos,
  • gobo rotate/shake,
  • beam shaping (shutters),
  • iris,
  • colour temperature correction,
  • prism (to create multiple copies of gobos, or dissolve effects)

Usually each feature (known as an attribute) is controlled by a separate channel. Attributes are adjusted by dials and trackballs/track pads on the lighting board (although not all lighting boards are compatible). With the functionality offered by modern fixtures and consequently the number of channels they consume, only modern control protocols such as DMX or Ethernet are used.

Moving Heads (or wigglers)

Moving Heads (or wigglers) have a motorised yoke to rotate the main part of the fixture. This allows the lantern to sweep across the X and Y axis', allowing the Lighting Designer to light almost any area of a stage. The body of the fixture contains motors to affect the beam e.g. filters to change the colour of the beam of light. There are two types of moving head lanterns:

Moving Wash Lanterns

Moving Wash Lanterns are used in a similar way to fresnels or PC's giving the designer the ability to light a broad area of space but also allowing them to light the area in a more colours than, typically, space would allow with generic fixtures. They may also have shutters with high speed stepper motors which can be used to create strobe effects.

Moving Spot Lanterns

Moving Spot Lanterns are like profile spotlights except that they are able to do multiple specials from a single position. They often have a pattern wheel which can accept a range of gobos. Some have prism wheels and rotators, which will change the way that the shaped beam is viewed.

Scanners (or scans)

Scanners (or scans) are mostly used in club lighting although they are sometimes used for specific effects in theatre lighting. Instead of tilting the main body of a fixture, it stays still and the beam is projected onto one or more moving mirrors, which 'scan' over the dance floor. Because only small mirror movements are required for large sweeps, beams can move faster, but be positioned less accurately. Some distortion of the beam may also occur. Different mirror arrangements exist, including the simple pan and tilt of a flat plane, the rotation of multifaceted drums or a combination of both to give different numbers of beams and movement patterns.

Colour Scrollers

Colour Scrollers fit onto the front of conventional lanterns (normally PARcans, but it can be fresnels and profiles). They allow the colour to be changed remotely. There are three types of scroller:

Single String

This is the most common type of scroller; it has one scroll which consists of separate pieces of gel taped together and can be anywhere from 2 to 32 sections long.

Dual String

These are very uncommon. By using two scrolls of gel, a certain degree of colour mixing is allowed.

CMY (Cyan, Magenta, Yellow) Strings

These are also very uncommon mainly due to their price. By combing three scrolls of gel of varying intensities any colour can be produced.

Gobo Rotators

Gobo Rotators strictly are an enhancement rather than a lantern in their own right. As their name suggests they slot into a lantern to allow a designer to rotate a gobo, often at variable speeds. This can give spectacular break ups and hypnotic swirls.

LED Pars and batterns

LED Pars and batterns have Light Emitting Diodes instead of Tungsten lamps, which offer colour RGB (red, green and blue) colour mixing and greater energy efficiency. The Thomas Pixel Par offers 16.7 million colour combinations, and whilst they are considered to be less 'punchy' than a traditional PAR64, the colour options make them infinitely more flexible. With increased energy efficiency comes a lower demand for power.

LED panels, Media Servers

Another exiting area developing is the use of media servers, which are gaining popularity though currently found only in large budget productions. These consist of a computer that manipulates images and video to be displayed by projectors, LED batterns or video walls, as specified by vast numbers of control channels.