Color scroller
From Wikipedia, the free encyclopedia
A color scroller or color changer is a lighting accessory used in theater, film, dance and concerts to change color gels on stage lighting instruments without the need of a person to be in the vicinity of the light. It is attached in the gel frame holder on the end of a lighting instrument. Most scrollers are controlled via DMX protocol but some new models (i.e. Wybron Coloram IT) are controlled via RDM protocol. When color scrollers first started showing up around 1980 a number of companies produced them including Avolites, Rainbow, Morpheus, GAM products, Rosco Laboratories and Wybron Inc. Now the main manufacturers are A.C. Lighting, Apollo, Morpheus, Rainbow and Wybron (in alphabetical order).[1]
Contents |
[edit] Types of scrollers
[edit] Single string scrollers
The most commonly used type of scroller is the single string scoller. This type has only one string of color anywhere from 2 to 33 frames long.
[edit] Dual string scrollers
Dual string scrollers use 2 strings (one behind the other) and allow for a form of CMY mixing. The Chroma-Q Cascade and the Wybron "CXI" uses 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 color positioned to either side of it. The first string has progressively denser yellow and cyan frames and the 2nd string 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" color mix. There is a limited ability to transition "live" between mixed colors - although some transitions cannot be accomplished without passing through the clear center frame.
[edit] CMY color-mixing scrollers
Finally, there are "true" CYM mixing scrollers that utilze 3 independently controlled gel strings - namely, the patented ColorFader system manufactured by Morpheus Lights of Redding, CA. Independent control of the gel strings permits users to crossfade "from any color to any color" directly (without going through undesired colors as on a single or double string color changer).
[edit] Other
Although not a color scroller, the High End System's Colormerge is often put in the category of color changers. It is a color mixing unit made to be used with the ETC Source Four ellipsoidal fixture. It is positioned in the unit between the lamp casing and the gate. It provides CMY color mixing via dichroic glass plates. "Colormerge" was a relatively expensive device which lacked reliablilty - these problem ultimately caused it to fail in the marketplace. It was discontinued in 2004. [2]
[edit] Sizes
Color 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 Inch - 7.5 Inch (fits ETC Source 4 19°, 26°, 36° and 50° units)
- 8 Inch - 10 inch (fits PAR 56 & 64 units)
- 12 inch (fits large sized Fresnel units like 2K units)
- 15 inch (fits bigger Fresnels, like 5K ones)
- 20-30 inch (fits Thomas 8 Light and Thomas 9 Light units)
- Large format scrollers for ETC Multi-PAR units
[edit] Control
Most color 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. The unit is then connected with other color scrollers by 4-pin cable and run back to a power supply. The power supply receives the DMX control signal from the light board and distributes control signal (DMX or proprietary) to each color scroller unit along with 24 volts DC.[3] Power supplies can power anywhere from 2 to 64 units.
Some color 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 "daisy 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 and highly reliable 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 to each ColorFader unit, the need to keep track of "head feet" is eliminated.
Some new models of scrollers are moving towards RDM protocol and are using small LED screens for addressing and other settings on the unit (like the new line of Wybron scrollers). This new method of control allows for easier addressing and the ability to 'talk-back' to each scroller (to get diagnostic information for example). Morpheus ColorFader3 units have direct push-button addressing for DMX with an LED display that provides complete set-up staus information for each unit.
Color 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 color string mixed color positions (for scrollers with multiple strings), preset effects/times, and control over the speed the string moves.
With the newer RDM protocol much more options are available without taking up channels of control. These 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 color, use, and if the string is broken). [4]
[edit] Example color string
Most companies offer two standard types of gel strings; one for theater and one for rock and roll. This is an example from Wybron Inc utilizing GAM colors. [5]
Wybron Theatre Colors 16 Frame String
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 Colors 16 Frame String
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 [6]
