Intelligent lighting

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High End Systems Studio Color, one of the more basic automated lights

Intelligent lighting refers to stage lighting that has automated or mechanical abilities beyond those of traditional, stationary illumination. Although the most advanced 'intelligent' lights can exhibit extraordinarily complicated effects, most lighting technicians agree that it is closer to 'obedient' lighting since the intelligence lies with the programmer of the show rather than the instruments or the lighting operator. For this reason, Intelligent lighting is also known simply as Automated lighting.

1 Features
2 Construction
3 Usage
4 History
5 References
6 See also
7 External links

[edit] Features

An automated light, properly called a luminaire, fixture or a moving head, is a versatile and multi-function instrument designed to replace multiple stationery lights. Depending on the venue and application, automated luminaires can be a versatile and economical addition to traditional lights because, with proper programming, they can swiftly alter many aspects of their optics, changing the 'personality' of the light very quickly. Lighting is typically pre-programmed and played back using only simple commands, although moving heads can be controlled "live" if the operator is sufficiently experienced.

XLR connectors, the most common method of controlling moving heads. Note however that these are 3-pin XLR cables rather than the 5-pin which is the industry standard

The vast majority of moving heads are controlled using the DMX protocol, usually using dedicated unshielded twisted pair cable with 5-pin XLR connectors at the ends^[1]. Each fixture is assigned a block of DMX "channels" in one of the venue's DMX "universes" (a self-contained set of cables and fixtures which can operate a maximum of 512 individual channels). The central lighting desk transmits data on these channels which the intelligent fixture interprets as value settings for each of its many variables, including color, pattern, focus, prism, pan (horizontal swing), tilt (vertical swing), rotation speed, and animation.

Ethernet cable, used in the most recently developed moving heads.

Since moving heads did not attain prominence until DMX's predecessor, analogue, had passed the zenith of its popularity, very few moving heads use analogue control (this is also due to crippling restrictions on bandwidth and data transfer speeds). Some of the most modern intelligent fixtures use RJ-45 or Ethernet cabling for data transfer, due to the increased bandwidth available to control increasingly complicated effects.

[edit] Construction

Intelligent fixtures usually employ compact arc lamps as light sources. They use servo motors or, more commonly, stepper motors connected to mechanical and optical internal devices to manipulate the light before it emerges from the fixture's front lens. Examples of such internal devices are:

Vari*Lite VL2500, an advanced automated fixture with many specialized functions and sensors.

Mechanical dimming shutters used to vary the intensity or 'strobe' the output. To the human eye, very high-frequency strobing has the same effect as electronic dimming: it varies the apparent brightness of the light.
Color wheels with dichroic color filters used to change the color of the beam.
Variable, incremental Cyan, Magenta and Yellow color-mixing filters to vary beam color via subtractive color mixing. Using this method, a much wider range of colors can be created than is possible using single color filters.
Automated lens trains used to zoom & focus the beam; irises are used to change the size of the beam. Some fixtures have as many as 10 independently controlled prisms or lenses to focus and shape the beam ^[2].
Pattern wheels with gobos and gate shutters to change the shape of the beam or project images. Some fixtures have motors to rotate the gobo in its housing to create spinning effects, or use their complicated lens systems to achieve the same effect.
Automated 4-blade framing shutters to further shape the beam and control unwanted spill.

These fixtures also use motors to enable physical movement of the light beam by:

Pivoting an automated mirror which reflects the beam along X & Y axes, or
Attaching the entire fixture lens train to a yoke with motorized pan & tilt

Note that fixtures which use the former method are not technically "moving heads", since the light source itself does not move. However, the term 'moving head' is used interchangeably throughout this article.

Martin MAC2000 profile, an automated fixture with many controllable parameters.

[edit] Usage

Intelligent lights can be used wherever there is a need for powerful lighting which must be capable of rapid and extreme changes of mood and effects. Moving heads would, therefore, be appropriate in a setting which does require strong lighting (such as a home) or where the 'quality' of the light required does vary excessively, although it may need to be very strong for a venue like a stadium). Naturally, there are exceptions to this rule, most notably the use of enormous numbers of moving heads for epic sporting events, such as the Commonwealth Games^[3], where nearly 1000 individual moving heads were used to light the opening and closing ceremonies of the XVIII Games in Melbourne.

Usually, however, the use of intelligent lights is confined to theatre, concerts and nightclubs, where the versatility of these fixtures can be utilised to its best extent. In these applications, the uses of fixtures can be informally grouped into two categories: 'active' and 'passive' (although these are not standardised terms).

Passive use of intelligent lights involves utilising their versatility to perform tasks which would otherwise require many 'dumb' lights to accomplish. For example, six to eight moving heads can create a textured blue 'night' effect on the stage floor while applying amber light to the actors during one scene - this can create a sensation of dusk or night. At the flick of a switch, the moving heads can change to an animated red 'fire' effect for the next scene. Attempting this transition with traditional lighting fixtures could require as many as thirty instruments. In this circumstance, the intelligent lights are not doing anything that could not be achieved using 'dumb' fixtures, but they dramatically reduce the number of lights needed in a rig.

The other use of intelligent lights is to perform tasks which would otherwise require human involvement, or be simply impossible with standard lights. For instance, a number of moving heads producing tightly-focused, pure white beams straight down onto the stage (especially if a smoke machine or hazer is used to make the beams visible) will produce a fantastic effect reminiscent of searchlights from a helicopter. To recreate such an effect without intelligent lights would require at least one human operator seated directly above the stage with a followspot, which would be prohibitively expensive and probably unsafe. Other features of moving heads, such as rotating gobos, simply cannot be duplicated by any 'conventional' lighting rig without the benefit of intelligent fixtures.

[edit] History

The first remotely controllable lighting system was the "Mac-spot", which was retrofitted onto a standard Par64 frame. It offered remote pan and tilt control, but no other features^[4]. The first fully controllable automated light system was originally implemented in 1972, at the State Theater of Basel, Switzerland ^{[citation needed]} with a controller that used punched paper tape as the cue recording/playback medium - a cumbersome, but visionary, system which was clearly ahead of its time. Advances in memory and storage technology in the decade that followed made the first modern computer controlled automated stage lighting system practical in the popular music concert industry in the early 1980's by Vari-Lite and other companies. As automated fixtures gained widespread acceptance in this market they evolved and their capabilities became more refined. These more sophisticated automated fixtures were increasingly used in theatre, television, and other entertainment lighting applications.