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Spring 2021 Joseph and the the and Joseph designer tryingtopaintthestagewithcolor, whilecoordinating withothercostume andscenicdesigners tocreate avividstageappearance. In the WinterIn Spectral powerdistribution Group forgive. will room There isalotof on theTSPfriends Photometrics Working imprecision thatIhopemyamount of level. atahigh things meansacertain That and chromaticity control keeping while differences between direct emitter control daily work. issue, This we’ll more look atthe more abouthow to control inour down theretaking apeek to understand interest to color scientists, but itisworth hole are thatrabbit mostly of depths of color. to describe fully The easytovery go down holeof arabbit color. As mentioned inthatarticle, itis thebasicchallenges around controllingof Protocol mazing mazing A , we went into some T reamcoat D echnicolor , basedonthestoryofJoseph in of theemitted photons,of andtherefore toused make theLEDchip, theenergy hole.the rabbit on thematerials Based that promisedarticle to down only peek interesting, too but much perhaps for an photon. physics The thisprocess isvery of intoan electron falls aholeitreleases a in asemiconductor junction, andwhen the recombination electrons andholes of encounter. LEDsproduce through from any source other light we commonly produce again, light itissodifferent because it isuseful to understand theprinciples. ingeneraluse,lab andthatneeded however precision ina needed between thelevel of It’s discussingtheway worth LEDs Spring 2021 26 Genesis , isafamily-friendlymusical, butit’s achallengefor a lighting small part of the spectrum theelectromagnetic of part small human vision, which isavery of the range we perceive them asblue. iswithin This photons and are energy higher we perceive them asred . Shorter wavelength photons are lower and energy photon isrelated to itswavelength. Longer photons, anindividual of andtheenergy come all but they down of to theenergy into abroaderspectrum spectrum. to convert anarrow or ultraviolet phosphorLEDs useanadditional coating emitted from narrow. anLEDvery White light specific. of That makes thespectrum theemittedthe frequencylight, of isvery There are many ways color, to describe By Javid Butler

Photo: Courtesy of Tulane University Spring 2021 dditionally, small changes in the small changes in the red Additionally, Joseph design Joseph to getting ready are So you being lit with set one of to another fixtures will the coat on move. appear to the colors that might intentionally be a done When if let’s but then it is coincidental effect, nice sings well Joseph playing hope the actor enough notices. that no one Dreamcoat, Technicolor and the Amazing in with show saturated colors other any or scenery—which or is pretty much costumes Lighting . Town than Our every other show it has , Town in Our role has a different the story tell to ofof years billion several the characters. history around happening the play. to the foreword read kidding, Not startfor select fixtures as you to Anyway, a look at the take lighting, are you the show designers are and costume the scenic colors is the fundamental point to remember with remember point to is the fundamental must Colors it. so I’llLED lighting, repeat in the light see them to besource in the If is source the a material. from reflected greens reflected will then in green not low the even If in blue, appear vibrant. it is low most electric will material blue appear dull. from strides the stage across as Joseph And emitting the same power as a red or blue LED will appear LED emitting the same power as a red A green 27 COL PROTO Colors must be in the source to see them see them to be in the source must Colors So far we have been the SPD discussing have So far we s plotted against the color response LEDs plotted against the color response and 650 nm red 550 nm green, Nominal 450 nm blue, (cones) in the human eye. sensitivity in that range. brighter due to the increased not well matched to the are If LEDs in a fixture affect color perception. can or blue dull. the scene could appear in sets and costumes, colors reflected with The a wide SPDs range of . a very smooth curve of have these sources withand materials very saturated colors LED Under will appear fairly consistent. can appear materials though, lighting, spectrum broad than under very different a that have materials particular, In sources. variety of can be difficult saturated colors will colors Some be vibrant light. whileto is problem A related appear dull. others as they change can appear to that colors say to another, LED fixture one from move Under the stage. across moves as an actor coat Technicolor light Joseph’s incandescent With consistently. to light difficult wasn’t look at why. Let’s LED that changes. That a material. in the light from reflected an idea ofan idea will we what see. colors look generally don’t we but of light sources, of and most at sources world our directly of surfaces. not consist white does matte challenge the is then where color Reflected such used light Historically sources, starts. spectrumsbroad have as sunlight and fire, ) shows us the color perception perception us the color ) shows Sunlight has a broad spectral Sunlight has a broad power because ourLED lighting gets complex overall. Within that range our eyes are that range are our eyes Within overall. in the middle photons to most sensitive as green. perceive of we which the range, of in milliwatts) (e.g., the power Taking and wavelength at each all the photons get the we a graph, plotting on them spectral distribution (SPD) ofpower the general the range In light being measured. be 400 nm of to vision human is considered though sometimes a wider 700 nm, to than longer range is used. so heat, or infrared, considered 700 nm are sometimes a spectral distribution will power the heat farther 800 nm or show to to go as the visual as well spectrum.produced distribution that is also fairly smooth, absorbs although in the atmosphere water evolved eyes and our frequencies, some sensitivity the spectrum to of sunlight as on the canopy the through tree filtered spectrum has a Fire that is African savannas. is also relatively but than sunlight, different a also have lamps Incandescent smooth. lamps discharge Most smooth spectrum. sharp multiple peaks spectrum, in their have by designed be perceived theybut to are light as a white our eyes selection through of of the number spectral peaks and they Low- fallwhere in the visible range. used as those such lamps, sodium pressure emission a narrow have in streetlights, though, Overall spectrum LEDs. similar to of in our perception light unusual LEDs are spectral very their narrow to due and color distribution. power at all energies photons not detect do eyes green less energy from takes It equally. our stimulate to 550 nm, around photons, at photons than blue photoreceptors color While at 650 nm. photons red 450 nm or spectral distribution us a lot tells power by it doesn’t ofabout the emission an LED, humans itself we about the color us much tell The luminosity efficiency will perceive. function V(λ and of frequencies, at different our eyes that with the spectralcombining power distribution of individual LEDs starts give to Spring 2021 everything youneed. capabilities, itmaynotgiveyou communication protocol, andconsole but dependingonthefixtures, Chromaticity controlcangetyouclose, noticeable colorchanges. increments inthebluerange, showinghowsmallchangesinchromaticity coordinates canproduce are larger orsmallerindifferent partsofthediagram. Solid linesshowincrements of0.5forxandychromaticity coordinates. Notehowcolorchanges in the sets and costumes,in thesets the especially comparedand where fall they to the colors the fixture.peaks in the emitters atthe Look havewill them from developed they when the manufacturers. they thetime Most of you don’t have theemitters, theSPDsof ask theLEDfixtures SPDs of you plan to use. If planning to use, andcompare them to the also be tricky,also be andnewer fixtures include a different .patterning of Greens can thematerial hastextures if or especially Differences noticeable, in blues very can be with the in thefixturesreds. alot canhelp thespectrum, amberor white LEDs ends of thered inboth andblue off falls function blues andgreens. While theluminosity Tick marksinthelowerleftshow0.1 Spring 2021 28 diagram, phosphor while converted LEDs thechromaticity near theedgeof as sitting LEDemitter anarrow spectrum think of wavelength. notasingle generally You can produce wavelengths, anarrow of range but wavelength.theoretically asingle LEDs arechromaticity pure diagram colors, seen. theCIE1931 Colors neartheedgeof or have arepeople familiarwith atleast the hole, feet. both notjump inwith we’ll So use and Ipromised to down just therabbit peek you need. capabilities, itmay notgive you everything communication protocol, andconsole youget close, but depending on thefixtures, uskeep going.of Chromaticity control can therest while for adrink freefeel to dashoff rehearsal. I’m notgoing you, to arguewith chromaticity coordinates dress during you any canselect color you wantthrough and controls have chromaticity control so aboutthat, toneed worry your fixtures the team can work together to find an answer. before isbuilt andcostumes staging sewn, so not working well, it’s better to know that elements.critical you finda If color thatis color every used, with help this with but will isthesame.principle It’s to do notpractical thancostumes, carpets this with but the In my current work, I’m more often doing under appear different material will lighting. I test different mixes to for afeel get how the totime how see thecolors appear. After that intheother emittersthen bring one ata one closest thematerial, to themaincolor of one emitter,under thelights. with Istart the fixtures, it’s good to check thematerials team. thedesign therest of with foot inthetheatre, andshare any concerns are you things cancheck before even setting with mint fixturesor lime emitters. These to help use green itwill shades of a lotof happen. thecostumes have or scenery If amber, andalittleblue, andwatch themagic green color, some red but mixthemor with by themselves asickly are they kindof a greenish phosphor converted LED, and “lime” or a “mint” emitter. are These often There are many different color systems, you areSome of thinkingthatyou don’t Once you have access to thestage and CIE1931 chromaticity diagram thatmost chromaticity diagram Spring 2021 . . n egas, NV egas, V

egas section of the egas section of the V is a lighting Butler is a lighting Javid and energy consultant based in Las M, and and CEM, He holds LC, and is CMVP credentials, the Education Chair for the Las Illuminating Engineering and Nevada Society, ngineers. Association of Energy Engineers. e can be reached at He can be reached at ax. When fine tuning color I find it helpful to I find it helpful color tuning fine When to how on depth into gone I’ve Here chapter of the He also writes science fiction under the pen name David P [email protected]. supported by the fixture, it is best to use 16- to use it is best fixture, the supported by full use that makes use an interface and bit, smallest the This gives of that resolution. Having diagram. the chromaticity on square and hopefully fixture step, E1.54 is the first willby manufacturers follow and controls format. the 16-bit implementing quickly the get into to coordinates use chromaticity emitter direct I’ll then to switch right area, precise That allows tuning. fine for control selection of the SPD that brings the out products as more Perhaps most vivid colors. format of the 16-bit implementing E1.54 tuning step that fine market the into come that at present but be needed as much, won’t well. works process with LED fixtures. problems color avoid spectrum new LEDs also offer Narrow advantage artistic Taking opportunities. of an those opportunities require does ofunderstanding here. the basics outlined of a new past the problems, Once us. design possibilities before opens come 29 COL PROTO E1.54 The Photometrics Working Group Group Working The Photometrics can affect the appearance of the material. can affect of the appearance the material. of the size determines resolution Control be from that can sent the smallest square of regardless can what the fixture controller, produce. ANSI E1.54 standard has developed aspects of the protocol that addresses the E1.54 uses only control. chromaticity eliminating diagram, CE1931 chromaticity and of selection, issue space any color the data structurefor also defines DMX512 over coordinates communicating Where depth. 16-bit 8- or in either chromaticity coordinates as a square, with as a square, coordinates chromaticity Fixtures in the center. the exact coordinates SPDs mightwith fall that inside different but same coordinates the when setto square square. the inside places still be different an like using smaller squares While in to achieve it is very difficult easy answer if use the same the fixtures Even practice. in the drive differences any LED chips, the operating of the age the LEDs, circuits, in the fixture factors and other temperature,

As we get closer to the middle of to get closer we a As

ing the 16-bit format of ing the 16-bit format Perhaps as more products implement - as more products Perhaps diagramchromaticity of the number SPDs at a specific setof a color that can create A fixture very large. becomes coordinates SPDs emitter with overlapping several the same color might produce be to able combinations different using coordinates This is important because of power. emitter sources lighting from the same material different SPDs can give with different the set to when both are even results, some To coordinates. same chromaticity of the precision on this depends extent Think of though. set of each the controls, including different whites along with along whites mint different including The total the center. to closer and lime are are produce range can of a fixture colors of gamut the by determined its emitters. think of to the locate it is to A simple way the diagram on a polygon and draw emitters inside color Any the perimeter. around fixture, the can be by made the polygon Total cannot. the polygon outside anything of combination to a the SPD equates fixture powers. individual emitter

won’t be needed as much . . . . much . won’t be needed as into the market that fine tuning step that fine tuning into the market