Intelligent lighting

A Martin MAC 550 intelligent light

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 produce extraordinarily complex effects, 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 as automated lighting, moving lights or moving heads.

History

There are many patents dating back from 1906, with Edmund Sohlberg of Kansas City. The lantern used a carbon-arc bulb and was operated not by motors or any form of electronics, but by cords that were operated manually to control pan, tilt and zoom.

1925 saw the first use of electrical motors to move the fixture, and with it the beam position, by Herbet F.King (Patent number: 1,680,685). In 1936 patent number 2,054,224 was granted to a similar device, with which the pan and tilt were controlled by means of a joystick as opposed to switches. From this point on until 1969, various other inventors made similar lights and improved on the technology, but with no major breakthroughs. During this period, Century Lighting (now Strand) started retailing such units specially made to order, retrofitted onto any of their existing lanterns up to 750 watts to control pan and tilt.

George Izenour made the next breakthrough in 1969 with the first ever fixture to use a mirror on the end of an ellipsoidal to redirect the beam of light remotely. In 1969, Jules Fisher, from Casa Manana area theatre in Texas saw the invention and use of 12 PAR 64 lanterns with 120watt, 12volts lamps fitted, 360 degrees of pan and 270 degrees of tilt, a standard that lasted until the 1990s. This lamp was also known as the 'Mac-Spot' ^[1]

In Bristol in 1968, progress was also being made, mainly for use in live music. Peter Wynne Wilson refers to the use of 1 kW profiles, with slides onto which gobos were printed, inserted from a reel just like on a slide projector. The fixtures also had an iris, a multiple coloured gel wheel. These lights were also fitted with mirrors and made for an impressive light show for a Pink Floyd Gig in London. Another fixture known as the 'Cycklops' was also used for music in the USA, although it was limited in terms of capabilities. With only pan, tilt, and color functions, and at 1.2meters long and weighing in at 97 kg including the ballast, they were heavy and cumbersome. These units were designed more for replacing the ever unreliable local spotlight operators.

In 1978 a Dallas, Texas based lighting and sound company called Showco began developing a lighting fixture that changed color by rotating dichroic filters. During its development, the designers decided to add motors to motorize pan and tilt. They demonstrated the fixture for the band Genesis in a barn in England in 1980. The band decided to financially back the project. Showco spun off their lighting project into a company called Vari-Lite, and the first fixture was also called the Vari-lite. It also used one of the first lighting desks with a digital core and this enabled lighting states to be programmed in.

Genesis was later to order 55 Vari-lites to use in their next chain of gigs across the UK. The lights were supplied with a Vari-Lite console which had 32 channels, five 1802 processors and a dramatic improvement of the first console which was very simple, had an external processing unit.

In 1986 Vari-Lite introduced a new series of lighting fixtures and control consoles. They referred to the new system as their Series 200, with the new lights designated "VL-2 Spot Luminaire", and "VL-3 Wash Luminaire". The Series 200 system was controlled by the Artisan console. Vari-Lite retroactively named the original system "series-100". The Original Vari-Lite console was retroactively named the "series 100 console" and the original Vari-Lite was retroactively named the "VL-1 Spot Luminaire" The prototype fixture shown to Genesis in 1980 was re-designated the "VL-zero" in the mid 1990's to keep the naming consistent.

In 1985, the first moving head to use the DMX protocol was produced by Summa Technologies. Up till that time, moving lights were using other communication protocols, such as DIN8, AMX, D54 and the proprietary protocols of other companies, such as VariLite, Tasco, High End and Coemar. The Summa HTI had a 250watt HTI bulb, 2 colour wheels, a Gobo wheel, a mechanical dimmer and zoom functions.

The first purchaseable/mass produced scanner was the Coemar Robot, first produced in 1986. Initially produced with either the GE MARC350 lamp, or the Philips SN250. Later versions were factory equipped with the Osram HTI400, a modification that High End Systems had been doing since 1987. The Robot used model aircraft servo motors to control Pan, Tilt, Color and Gobo, with the gobo wheel providing the shutter function as well. The Color wheel had 4 dichroic color filters ( Red, Blue, yellow, and Green), and the gobo wheel contained 4 stamped patterns (non-replaceable). The Robot communicated with a proprietary 8bit protocol, yet had no microprocessors/pal's/pics/ram, O/S or other modern logic device.

In 1987, Clay Paky began producing their first scanners, the Golden Scan 1 & Crystal Scan. They utilised stepper motors instead of servos and used a HMI 575 lamp, bright and with a far more uniform beam brightness. This was followed by the Intellabeam in 1989, released by High End, who, at the time were the Distributors for Clay Paky.

In the 1990s, the future came closer with Martin, a Danish Company producing Fog Machines. They manufactured a line of scanners known as the Roboscans, with a variety of different specs for different users. Their range started with the 1004, 1016 later the 804, 805 for the small venue and went up in brightness and features through 218, 518, 812, 918 and 1200Pro units. Martin also invented a whole new range of Moving Heads including the Mac250, the Mac250+, Mac300, Mac500,Mac 550, Mac600, Mac700, Mac1200 and more recently the Mac2000 and MacIII. Martin Mac's are popular in most rental situations and are also a great compromise between the cheaper manufactured products and the top end luminaires such as a High End DL2.

The future promises many great things as the concept of digital lighting, a bright LCD or DLP projector mounted in a yoke or moving head type fixture with an integrated media server will allow for millions of colour choices, endless libraries of gobos, image and video projections to take place.

Features

Several intelligent lights in use at a concert. Note the white beams they produce

An automated light, properly called a luminaire, fixture (or sometimes moving head), is a versatile and multi-function instrument designed to replace multiple conventional, non-moving lights. Depending on the venue and application, automated luminaires can be a versatile and economical addition to a stock of 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.

Most moving heads have all or some of the features, each feature is set to a channel number, such as this:

• Pan
• Tilt
• Fail
• Fine Pan
• Fine Tilt
• Dimmer
• Shutter
• Gobo1 Select
• Gobo1 Rotation
• Gobo2 Select
• Gobo2 Rotation
• Gobo3 Select
• Colour1
• Cyan
• Magenta
• Yellow
• Prism 3,5,9facet
• Prism Rotation
• Effects Wheel
• Gobo Animation Wheel
• Iris
• Lamp Shut off, fixture reset
• Remote patching channel

Control

Moving lights are controlled in many ways. Usually the fixtures are connected to a Lighting control console, which outputs a control signal. This control signal sends data to the fixture usually in one of three ways: Analogue (which has largely been phased out), DMX (which is the industry standard control protocol), or Ethernet Control (which is still in development). The fixture then takes this signal and translates it into internal signals which are sent to the many stepper motors located inside.

XLR connectors, the most common method of controlling moving heads. Note that these are 3-pin XLR connectors, which are used by some manufacturers, rather than the 5-pin, which specified by the USITT DMX-512 Standard.

The vast majority of moving heads are controlled using the DMX protocol, usually using dedicated twisted pair, shielded cable [1] with 5-pin XLR connectors at the ends.^[2] 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.

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, data transfer speeds and potential inaccuracy). 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. Using the new Ethernet technology, control surfaces are now able to control a much larger array of automated fixtures.^[3] Because many devices can be connected to a single RJ-45 network, these devices have the ability to not only listen to a control signal from a lighting control board, but have the ability to transmit information back to the control board and other entities on the network. Now, it is possible for a fixture to self-diagnose any problems, announce itself on a network, or accept setting changes from any place on the network, making obsolete older versions of the system that only had one central brain, the lighting control board. Because RJ-45 (and equivalent technologies) use bidirectional digital communication, bit-checking abilities allow for lighting control networks to safely operate devices that can interfere with human safety (pyrotechnic devices, rigging mechanisms, etc.).^[4]

Moving lights are programmed using a fixture box in ETC light boards

Moving lights are much more difficult to program than their analogue cousins because they have more attributes per fixture that must be controlled. A simple conventional lighting fixture uses only one channel of control per unit: intensity. Everything else that the light must do is pre-set by human hands (colour, position, focus, etc.) An automated lighting fixture can have as many as 30 of these control channels. A slew of products are available on the market to allow operators and programmers to easily control all of these channels on multiple fixtures. Lighting boards are still the most common control mechanism, but many programmers use computer software to do the job. Software is now available that provides a rendered preview of the output produced by the rig once fixtures are connected to the program or console. This allows programmers to work on their show before ever entering the theater and know what to expect when the lights are connected to their controller. These products usually feature some method of converting a computer's USB output to a DMX output.

The latest generation of moving heads ^[5] are integrating digital projection capabilities, creating a real convergence between lighting and video projection. These new generation of heads do not only require intensity, position and focus control, but will require video content control as well.

While it is true that moving lights have, in a sense "revolutionized" the world of concert and other event lighting, to call these fixtures "intelligent" can be offensive to some people. In fact, not every person involved in the music production business feels that moving lights are intelligent, necessary or even desirable at all. While this type of technology can be used very effectively, there are many instances in which it simply distracts an audience from the lack of musical content coming from the stage. In this case, to call this lighting "intelligent" can be the source of much confusion.

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:

• Mechanical dimming shutters used to vary the intensity of the light output. Mechanical dimmers are usually a specially designed disk or a mechanical shutter. Shutters with high speed stepper motors can be used to create strobe effects.
• 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.^[6]
• Automated lens trains used to zoom and focus the beam; irises are used to change the size of the beam. Some fixtures have as many as 10 independently controlled prisms and lenses to focus and shape the beam.^[7]
• 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 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 either:

• 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.

Usage

5 Moving Yokes Lighting up a Mirror Ball

Intelligent lights (now commonly referred to as automated or moving heads), 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 inappropriate in a setting which does not require strong lighting (such as a home) or where the “quality” of the light required does not 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 large numbers of moving heads for international sporting events, such as the Commonwealth Games^[8] or Olympic Games,^[9] where many thousands of separate automated fixtures are often used to light the opening and closing ceremonies. The 2008 Summer Olympics, in Beijing, had a rig of around 2,300 intelligent fixtures which is "the largest single automated lighting system ever assembled for a single event"^[10]

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 automated lighting involves utilizing their versatility to perform tasks which would otherwise require many conventional 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 fixture 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 automated fixtures are not doing anything that could not be achieved using conventional fixtures, but they dramatically reduce the number of lights needed in a rig. Other features of automated fixtures, such as rotating gobos, are also possible with conventional fixtures, but are much easier to produce with intelligent fixtures.

A martin mac 250 entour (profile - top) and mac 250 wash) wash - bottom).

Active use of automated lights, suggests that the luminaire is used to perform tasks which would otherwise require human involvement, or be simply impossible with conventional fixtures. For instance, a number of moving heads producing tightly focused, pure white beams straight down onto the stage will produce a fantastic effect reminiscent of searchlights from a helicopter (especially if a smoke machine or hazer is used to make the beams visible). 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 generally be considered to be too expensive for such a small effect.

Moving head fixtures are often divided into spot and wash lights. They vary in use and functions, but many companies offer profile and wash versions of the same model of light. Profile lights generally contain features like gobos and prisms, whereas wash lights have simpler optics and a wider beam aperture resulting in wider beam angle, which may be altered by internal lenses or “frost effects”. Wash lights are more likely to have CMY colour mixing although it is common for high-end spot lights to have such features too. Spot units are generally used for their beam effect (usually through smoke or haze) and the ability to project texture, whereas wash lights tend to be used for providing a stage wash.

A martin mac 250 entour (profile - top) and mac 250 wash) wash - bottom). Notice the difference in beam characteristics caused by the gobo of the entour and the wider beam angle of the wash.

Steampunk/DYI Moving Fixture

Debate

• Not all the light fixtures that have movement can be defined as intelligent. Basic club lighting is not controllable other than basic on and off. This lack of features makes them just a small step above a conventional Stage lighting instrument.

• Moving mirrors are faster than moving head fixtures. However moving heads are visually more interesting, and have a far larger range of movement. The movement from mirror lights tends to be rectilinear, because the centre of movement for both axis is usually in the same place, while one axis of a moving head luminaire describes a circle (usually called "pan") and the other (the "tilt") changes the diameter of the circular movement. In early luminaires a pseudo rotating gobo effect could be achieved by moving the tilt in line with the other axis and then moving the pan from end stop to end stop.

See also

• Stage lighting instrument

References

1. ^ http://www.mts.net/~william5/history/hol.htm - scroll down to "Early Automated Lighting" ~1970
2. ^ DMX512 Control Protocol Information - Connectors and Cables
3. ^ Cadena, Richard (2006). Automated Lighting. Focal Press. pp. 56–58. ISBN 978-0-240-80703-4. 
4. ^ LeMaitre FireCtrl Device, An example pyrotechnic control device that can accept RJ-45 control.
5. ^ Barco | Barco’s digital moving luminaire tears down boundaries between projection and lighting
6. ^ Cadena, Richard (2006). Automated Lighting. Focal Press. pp. 253–254. ISBN 978-0-240-80703-4. 
7. ^ Product - MAC 2000 Profile
8. ^ Casestory - XVIII Commonwealth Games, Melbourne, Australia
9. ^ MA Lighting On Beijing Olympics 2008
10. ^ Martin Lights Beijing Summer Olympic Games

External links

• Moving-lights - repository of technical info