A colour scroller or colour changer is an electro-mechanical lighting accessory used in theater, film, dance and concerts to change the colour projected by stage lighting instruments without the need of a person to be in the vicinity of the light. A colour scroller moves plastic "gel" colour gel [actually dyed polyester and/or other base materials coated with dyes] into the beam of the light. It is generally attached to the gel frame holder at the transmitting end of a lighting fixture, so colour is introduced after the beam characteristics have been defined by the optics of the lighting instrument. Most scrollers are controlled via DMX512 protocol, but some models (e.g. Wybron's Colouram IT) also utilize the RDM protocol. When colour scrollers were first introduced around 1980, a number of companies produced them, including: Avolites, GAM Products, Morpheus Lights, Rainbow, Rosco Laboratories and Wybron Inc. Now the main manufacturers are: A.C. Lighting, Apollo, Morpheus Lights and Rainbow (in alphabetical order).
Interior view of a Chroma Q 6" single string scroller, with scroll.
Single string scrollers
The most commonly used type of scroller is the single string scroller. This type has only one string of colour anywhere from 2 to 33 frames long.
Dual string scrollers
Dual string scrollers use 2 strings (one behind the other) and allow for a form of CMY mixing. The Apollo MXR 2, Chroma-Q Cascade and the Wybron CXI use 2 gel strings to obtain a CMY mix. One frame of clear gel is positioned at the center of each gel string (50% DMX) with progressively denser frames of colour positioned to either side of it. The first string has progressively denser yellow and cyan frames and the second string has progressively denser yellow and magenta frames. This permits various YC, YM, and CM combinations to be achieved as a "static" colour mix. There is a limited ability to transition "live" between mixed colours - although some transitions cannot be accomplished without passing through the clear center frame.
CYM colour-mixing scrollers
Finally, there are "true" CYM mixing scrollers that utilize three independently controlled gel strings - namely, the "ColorFader" system manufactured by Morpheus Lights of Las Vegas, NV, USA. Independent control of the gel strings permits users to cross-fade "from any color, to any color, anytime" directly (without going through undesired colours as on a single or double string colour changer).
The ColorFader system predated the dichroic systems used in most moving lights, to create smooth colour transitions. The basic concept of both systems is identical. Colour density variation is achieved by starting with a full-density sheet of gel (or dichroic glass) in either Cyan, Magenta or Yellow. The saturation of that colour is varied by perforating the gel sheet (or ablation of the dichroic) in a manner that permits unfiltered white light to pass through in varying amounts, progressing from full white to the fully saturated colour.
At the zero DMX "start" position on a ColorFader scroll there is a piece of clear gel (which is perforated with large holes to maximize light transmission). As the DMX control value is increased the gel string moves to the coloured gel, which has perforated holes are that are large and plentiful - so the percentage of white light passing through those hole predominates over that of the gel colour, and low-saturation colours are achieved. As DMX control value increases, it progresses the scroll further and the holes become smaller and less numerous - so the percentage of coloured material in the optical path increases relative to the white light pass-through, and the result is progressively higher density colour transmission. Ultimately, at full DMX, a solid, unperforated sheet of gel is positioned in the optical path - for full saturation.
Sizes
colour scrollers come in many different sizes and are mountable on nearly every type of conventional lighting instrument. Sizes include:
4 Inch (for smaller PAR 36 units)
6 to 7.5 Inch (fits ETC Source 4 19°, 26°, 36° and 50° units)
8 to 10inch (fits PAR 56 & 64 units)
12inch (fits large sized Fresnel units like 2 KW tungsten units)
15inch (fits bigger Fresnels, like 5KW tungsten or 2.4 KW HMI units)
20-30inch (fits Thomas 8 Light and Thomas 9 Light units)
Large format scrollers for ETC Multi-PAR units
Control
Input interface on a Chroma Q 6" scroller.
Most colour scrollers use DMX512 addressing protocol. Each scroller unit is given an address or identifying number. Earlier scroller models used binary DIP switches to set the address, however most scrollers currently include digital addressing systems. Once addressed, the unit is then connected with other colour scrollers and run back to a power supply (typically with 4-pin XLR cable. 4-pin is used to differentiate power lines from data.) The power supply receives the DMX control signal from the Lighting control console and distributes control signal (either DMX or a proprietary manufacturers signal) to each colour scroller unit along with 24 volts DC. Depending on the manufacturer, power supplies can power anywhere from 1 to 64 units.
Some colour scrollers are configured for "daisy chain" connection, by which 4-pin power/control cable feeds into and then out of a number of scrollers. The number of units that can be daisy chained together is limited by a head-feet restriction. Head-feet is defined as the total sum of the lengths of cable from each device to a single power supply. It is a way to account for the voltage drop in the power/signal cable caused the current drawn from each unit and the length of the cable. If you exceed the recommended "head feet" you may experience performance problems with all of the scrollers on the chain.
Other scroller systems, such as the Morpheus ColorFader, do not permit daisy chaining. Up to six standard ColorFader units (SFader or MFader) can be powered from a ColorFader PS-6 power supply - which is a simple unit that is generally hung on a pipe in close proximity to the active ColorFader units. Because independent "Home runs" (uninterrupted connection) of 4-pin cable reliably carry power and control signal directly to each ColorFader unit, the need to keep track of "head feet" is eliminated.
Some new models of scrollers are moving towards the RDM protocol and are using small LED screens for addressing and other settings on the unit. This new method of control allows for easier addressing and the ability to "talk-back" to each scroller (to get, for example, diagnostic information). Morpheus colourFader3 units, among others, have direct push-button addressing for DMX with an LED display that provides complete set-up status information for each unit.
colour scrollers utilize from 1 to 4 channels depending on their capabilities. One channel is required for every string of gel (up to 3) and one channel is required for optional control settings. Optional settings include: Remote fan control (ability to control the fan's speed and on/off status), preset colour string mixed colour positions (for scrollers with multiple strings), preset effects/times, and control over the speed the string moves.
With the newer RDM protocol many more options can now be made available. These can include: Light sensor (to see if the fixture the scroller is attached to is on), temperature sensor, voltage sensor, timers, fan control, self test, gel string sensor (gives info on colour, use, and if the string is broken). [dead link] Although RDM provides significantly more options, few manufacturers have yet implemented these features into existing products.
Colour strings
Most companies offer two standard types of gel strings generally referred to as "theater" and for "rock and roll". Typically, the theatre scroll will contain subtler colours, while the rock and roll scroll will contain more saturated shades. A number of scroller manufacturers and third party vendors offer scrolls made with custom colours, assembled to a customer's specifications, though these are non-standard items and carry a premium. A custom adhesive, known as high-temperature scroll tape, is also available to allow technicians to repair sections of scrolls that have become damaged. This scroll tape also allows for the fabrication of unique custom scrolls, although the cost in materials generally precludes the mass production of "home made" scrolls.
Example
Below is an example, from Wybron Inc utilizing GAM colours , of a typical scroll set. Note that the first position on the scroll is actually a clear piece intended to affix the scroll to the scroller.
Wybron Theatre 16 Frame String
Position
Code
Description
1.
Clear Leader
2.
G480
Medium Yellow
3.
G385
Light Amber
4.
G340
Light Bastard Amber
5.
G335
Coral
6.
G345
Deep Amber
7.
G270
Red Orange
8.
G195
Nymph Pink
9.
G120
Bright Pink
10.
G970
Special Lavender
11.
G948
African Violet
12.
G720
Light Steel Blue
13.
G810
Moon Blue
14.
G850
Blue (Primary)
15.
G540
Pale Green
16.
G690
Bluegrass
Wybron Rock-n-Roll 16 Frame String
Position
Code
Description
1.
Clear Leader
2.
G450
Saffron
3.
G345
Deep Amber
4.
G355
Amber Flame
5.
G245
Light Red
6.
G250
Medium Red XT
7.
G120
Bright Pink
8.
G995
Orchid
9.
G948
African Violet
10.
G930
Real Congo Blue
11.
G810
Moon Blue
12.
G835
Aztec Blue
13.
G850
Blue (Primary)
14.
G710
Blue Green
15.
G690
Bluegrass
16.
G655
Rich Green
Dichroic colour changers
Introduced as an alternative to a colour scroller, High End System's colourmerge unit was an add-on dichroic colour changer. It was a colour mixing unit made to be used with the ETC Source Fourellipsoidal fixture. Unlike a traditional colour scroller, it was installed inside the unit between the reflector assembly and shutters. It provided CMY colour mixing via dichroic glass plates. "colourmerge" was a relatively expensive device which lacked reliability - these problem ultimately caused it to fail in the marketplace. It was discontinued in 2004. [dead link]
More recently, the SeaChanger line by Ocean Thin Films accomplishes much the same thing but features a wide range of patented dichroic colour wheels in an array of saturation levels, for added colour possibilities. The SeaChanger unit is also much larger than the colourmerge and completely replaces the shutter assembly of a Source Four fixture. The SeaChanger has achieved a much higher level of commercial success.
In 2009, Morpheus Lights introduced the PacificFader line of dichroic colour changers, which were specifically developed for use with the modular Selecon Pacific ellipsoidal fixtures manufactured by Philips Entertainment. PacificFader units were available with either 3, 4, or 5 control parameters: PacificFader3 provided C,Y,M colour mixing for use with tungsten fixtures. PacificFader4 added a smooth optical dimmer/douser to the C,Y,M control, for use with energy efficient arc sources (CDM, MSR, MSD). The top-of-the-line PacificFader5 adds Morpheus' extended range CTO filter, which could either be used to colour-correct daylight sources to match tungsten units or to "bend" the CYM colour mix for additional subtle colour control.
Color temperature is a parameter describing the color of a visible light source by comparing it to the color of light emitted by an idealized opaque, non-reflective body. The temperature of the ideal emitter that matches the color most closely is defined as the color temperature of the original visible light source. Color temperature is usually measured in kelvins. The color temperature scale describes only the color of light emitted by a light source, which may actually be at a different temperature.
An interference filter, dichroic filter, or thin-film filter is an optical filter that reflects some wavelengths (colors) of light and transmits others, with almost no absorption for all wavelengths of interest. An interference filter may be high-pass, low-pass, bandpass, or band-rejection. They are used in scientific applications, as well as in architectural and theatrical lighting.
Stage lighting is the craft of lighting as it applies to the production of theater, dance, opera, and other performance arts. Several different types of stage lighting instruments are used in this discipline. In addition to basic lighting, modern stage lighting can also include special effects, such as lasers and fog machines. People who work on stage lighting are commonly referred to as lighting technicians or lighting designers.
In theatre, a lighting designer works with the director, choreographer, set designer, costume designer, and sound designer to create the lighting, atmosphere, and time of day for the production in response to the text while keeping in mind issues of visibility, safety, and cost. The LD also works closely with the stage manager or show control programming, if show control systems are used in that production. Outside stage lighting, the job of a lighting designer can be much more diverse, and they can be found working on rock and pop tours, corporate launches, art installations, or lighting effects at sporting events.
A color gel or color filter, also known as lighting gel or simply gel, is a transparent colored material that is used in theater, event production, photography, videography and cinematography to color light and for color correction. Modern gels are thin sheets of polycarbonate, polyester or other heat-resistant plastics, placed in front of a lighting fixture in the path of the beam.
DMX512 is a standard for digital communication networks that are commonly used to control lighting and effects. It was originally intended as a standardized method for controlling stage lighting dimmers, which, prior to DMX512, had employed various incompatible proprietary protocols. It quickly became the primary method for linking controllers to dimmers and special effects devices such as fog machines and intelligent lights.
A lighting control console is an electronic device used in theatrical lighting design to control multiple stage lights at once. They are used throughout the entertainment industry and are normally placed at the front of house (FOH) position or in a control booth.
Ellipsoidal reflector spot is the name for a type of stage lighting instrument, named for the ellipsoidal reflector used to collect and direct the light through a barrel that contains a lens or lens train. The optics of an ERS instrument are roughly similar to those of a 35 mm slide projector.
Remote Device Management(RDM) is an addition to the DMX512 control protocol for stage lighting equipment, introduced in 2006. DMX512 was developed in the late 1980s as a standard protocol for lighting consoles to communicate with dimmers, but has since been used for more complex applications, including the control of intelligent lighting fixtures. The addition of RDM addresses many of the shortcomings of DMX512, which is unidirectional with no support for metadata.
A parabolic aluminized reflector lamp is a type of electric lamp that is widely used in commercial, residential, and transportation illumination. It produces a highly directional beam. Usage includes theatrical lighting, locomotive headlamps, aircraft landing lights, and residential and commercial recessed lights.
Intelligent lighting refers to 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 human lighting designer, control system programmer, or the lighting operator, rather than the fixture itself. For this reason, intelligent lighting (ILS) is also known as automated lighting, moving lights, moving heads, or simply movers.
Stage lighting instruments are used in stage lighting to illuminate theatrical productions, concerts, and other performances taking place in live performance venues. They are also used to light television studios and sound stages.
In theatre, an electrician is a person who works with the various aspects of lighting. Some of the positions among electricians include the lighting supervisor, master electrician, deck electrician, light board operator, moving light programmer, followspot operator, as well as simply electricians. This group is generally known as the "Electrics" Department or LX Department.
A multifaceted reflector light bulb is a reflector housing format for halogen as well as some LED and fluorescent lamps. MR lamps were originally designed for use in slide projectors, but see use in residential lighting and retail lighting as well. They are suited to applications that require directional lighting such as track lighting, recessed ceiling lights, desk lamps, pendant fixtures, landscape lighting, retail display lighting, and bicycle headlights. MR lamps are designated by symbols such as MR16 where the diameter is represented by numerals indicating units of eighths of an inch. Common sizes for general lighting are MR16 and MR11, with MR20 and MR8 used in specialty applications. Many run on low voltage rather than mains voltage alternating current so require a power supply.
The SeaChanger Color Engine is an electro-mechanical device that is used to control light color in entertainment-industry lighting applications. The unit employs four overlapped color filter wheels, inserted into a light beam near its source, to produce colored light. This is in contrast to color scrollers, which insert color filter ribbons into a light beam. The color engine, which was released by Ocean Thin Films in 2005, is designed to fit into the Source Four lighting instrument made by Electronic Theatre Controls.
LED stage lighting is a stage lighting technology that uses light-emitting diodes (LEDs) as a light source. LED instruments are an alternative to traditional stage lights which use halogen lamp or high-intensity discharge lamps. Like other LED instruments, they have high light output with lower power consumption.
Vari-Lite is a brand of automated, variable-colour stage lighting systems. Their intelligent lighting fixtures are commonly used in theatre, concerts, television, film and corporate events.
Holiday lighting technology has been subject to considerable development and variation since the replacement of candles by electric lights. While originally used during the Christmas holidays as Christmas lights, modern electric light arrays have become popular around the world in many cultures and are used both during religious festivals and for other purposes unconnected to any festivities.
DJ lighting is a variant of stage lighting that is used by mobile DJs and in nightclubs. DJ lighting is generally used by mobile disco DJs and in most modern nightclubs and many late-night bars.
Stage lighting accessories are components manufactured for conventional (non-automated) stage lighting instruments. Most conventional fixtures are designed to accept a number of different accessories designed to assist in the modification of the output. These accessories are intended to either provide relatively common functionality not originally provided in a fixture, or to extend the versatility of a lighting instrument by introducing features. Other accessories have been designed to overcome limitations or difficulties some fixtures present in specific applications.
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