summer 2013 blue. R parameters” thanred, rather green, and parameters. N to control it: andthree intensity color controlabstract allocates four handles luminaire to usethree DMXchannels, S you canhave level. intensity avirtual control, abstract instead use some of form luminaires usingpure DMXlevels but I definition ofcolor Control and are better ways. theseluminaires.could off easily turn T would alsobuild a “color black” sothey color. T andkeepeasily roll the down thebrightness controlintensity channel. You could not DMX512 control channels andnosingle luminaires suchof asthesewassimply three and blue filters. I three MR16lamps,with fittedred, green, luminaire thathad wasaspotlight Iused control tricky. canbe T luminaires the same surface, hitting but it for years on gelled cycloramas with nothing new to ourindustry. We’ve done and intensities. multiple sources to achieve different colors tamed. 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T some Luckily, turning a light and off. on drive to you allow systems modern control typeany in very of simple system color ways. R parameters: distinct color three just HSV. and HSL, CMY, S the possibilities. examine C multiple are there hue one tricky; any for that can chip each of to combinations power space. the color point in that one to get you lighting with cyc the and we’re a musical a doing We’re mixing luminaires. color and the designer wants a sunset scene, the Using pink. to amber transition from R and cue 2 is pink B=0%) G=60%, B=60%). (R=100% G=0%, , A, hese nitially, nitially, GB his made the the his made GBW, with broad- GBW, Figure 3 Figure Figure 2 Figure W). W). A D colors became available became available LED colors ew GB his enlarges the gamut, giving us the gamut, his enlarges nother variationnother is R D technology continued to advance, advance, to s LED technology continued A A Ds. Luminaires exist that exist Luminaires spectrum LEDs. white and amber with use white other the three (R colors (deep systems been used in seven-color have and royal blue, cyan, green, amber, red, red, T blue). colors. more potentially chip manufactures managed to make deep deep make managed to manufactures chip T too. LEDs, blue and royal cyan, red, the most popular integrationthe most popular was R T with an added amber chip. that was sort gamut ofcolor triangular rectangular. more the market. Lighting designers’ appetites appetites Lighting designers’ the market. and along grew light this new for source with brighter for that came demand color consistent and more luminaires N control. I violet. and cyan, amber, white, too: Resolution Calibration Solid-state response time is instantaneous, When you are using 20 LED luminaires so if you stop driving the chips, they just to wash a cyc, variations in LED output stop making light. This is problematic when can easily be seen. For this reason, high- dimming LEDs: Slow fades using low- end solid-state luminaires have built-in resolution control, particularly at low levels, calibration channels. These channels allow end up looking choppy. Early-day LED you to dampen or boost the control level luminaires did nothing to compensate for going to each chip. You can achieve the low-resolution control, but more recently, same results by tweaking your color palettes advanced LED drivers have added shock for each luminaire; if one luminaire is absorbers in their firmware to smooth out consistently redder than the rest, you can the bumps. pull down the red at a global level and hope Using 16-bit control (two data slots things fall in line. I’ve found over the years, Figure 6 together) is another way luminaire if you have a picky designer that doesn’t like manufacturers have solved the issue of the look of a cue, you have to keep tweaking As these are purely hypothetical color choppy fades without having to add it. It is useless to argue saying it should be spaces (and we’re running out of letters), software shock absorbers. This puts the right because the desk said so. The designer we’ve dubbed this the prime version of HSL, onus on the control desk to push lots of always has the final say. HSL'. If you read carefully above, you will data, versus having to over-sample the data see that amber was defined having a hue' at the luminaire and predict where the of 10%. The ' after the triplet defines the level is going. Doing this prediction can Correlated Color mirror image of the color wheel. Regardless drastically delay the response time you get of your luminaire’s primary color system out of the LED luminaires, which is a bad Temperature (RGB, RGBA, RGBW, or RGBAW), it’s The International Commission on thing when you’re trying to bump them in possible to write cues and do transition in Illumination (CIE) describes Correlated time to the music. multiple color spaces (RGB, CMY, HSL, Color Temperature (CCT) as “the HSL', HSV, HSV'). temperature of the Planckian radiator whose Curves perceived color most closely resembles that of Another topic worth mentioning as a given stimulus at the same brightness and Making LEDs look like some LED luminaire manufacturers under specified viewing conditions.” I am not incandescent luminaires have incorporated it in their firmware, is a lighting scientist, so I describe it as the color of white. Another attribute some of these modern- intensity curves. Dimmer manufacturers Correlated Color Temperature is typically day LED luminaires offer is amber-drift or have often allowed you to tweak the curves quantified in Kelvin. To give you an idea of red-shift. When an incandescent luminaire’s that translate the incoming control level what the different values of Kelvin might lamp filament cools (dims toward off), it to the actual power output of the dimmer. represent when describing white light: A becomes more red, just like 2,800 K appears Common curves are linear, inverted, candle is about 1,800 K, a domestic light more red than 5,600 K. In practice, we and square-law. An LED’s instantaneous bulb is about 2,800 K, a theatrical spotlight choose colors assuming the luminaire is at response time can be used with great effect is 3,200 K, daylight is 5,600 K, and TV full, but we don’t often drive luminaires at when you want a quick strobe, but it can screens can be upward of 10,000 K. full in the theater, therefore we don’t often look unnatural when you have a mixed rig Can intelligent luminaires with tunable see 3,200 K on stage. It’s more like 2,800 K, and you hit the blackout button. The LEDs color define white too? Sure they can, but and as we approach a blackout, things do in go off in a split second, but high wattage it can be difficult given there are so many fact get quite red. Even if you’re using bluish conventional luminaires take almost a full flavors of white. For that reason, we can gels, you can see this effect. second to cool enough that no perceived allocate another parameter when dealing To help integrate theatrical LED luminaires light hits the stage. Some manufacturers with color mixing luminaires called CCT. into conventional rigs, manufacturers favor offer various curves on the LED luminaires For any luminaire, whether you choose to the red chip at the bottom end. This profiling such as Quick, Standard, Linear, and control it in RGB, HSL, or HSV', you can makes the colors at very low-light levels Tungsten emulation modes. What this does also dial in a white in Kelvin. If you want of conventional luminaires and solid-state is essentially retard the control levels sent to pure red, the definition of white is rather luminaires match more closely. the LED drive systems, giving it inertia.

30 summer 2013 summer 2013 n

and and 31 is the Robert Bell is the Controls Product Manager Connectivity, for Pathway is He Acuity Brand. an the author of the book A Control sits on the PLASA Control Protocols Working Group. He is a board member Russell Wally of the Robert can Foundation. be reached at rbell@ pathwayconenct.com. Let There Be Light Figure 8 Figure PROTOCOL hoose the system that helps that helps hoose the system dvanced abstract control systems go a a go systems abstractdvanced control you realize what you see in your head, and and head, see in your what you realize you and easily stage get it on let it help you it too. can appreciate so others quickly D luminaire. particular of out color D luminaire. an LE A simplifying to of some way long these stage want on getting what but you tasks, the take can be a daunting task if don’t you and what the console understand time to they interact with and how do luminaires C other. each f you o simplify it, o simplify it, Figure 7 Figure he two images below show the full color the full color show below images he two

T D turning an LED on can tell, s you A is not as simple as switching luminaire I bed. light your the reading by on all the methods of discussed take control the permutations and and do here than more are there likely it’s combination, methods of one 100+ different getting any Conclusion meaningless, so we ignore it, but as you as you but it, ignore so we meaningless, the and drive interject we white, approach the particular that achieves in a way chips T of defined. you version white might white LED fixture, in a three-color likewise, but at fulluse all power, chips the red drive CCT may at a different white and the than the blue a little harder chip chips. green spectrum, but the middle of the circles show the middle of but spectrum, show the circles at CCT one of versions white, different two CCT 6,000 K. at 3,200 K and the other