Light Cue 23

It has been a lot of fun writing this series and numerous people have said to me how useful they have found it. Below is an index of the articles in the series for quick reference.

Enjoy!

• Hue
• Saturation and Chroma
• Missing Color Syndrome
• Dominant and Recessive Colors
• Color Correction
• Additive vs. Subtractive Color Mixing
• Gray
• The Effect of Lamp Type

For the last installment in my series about Color Theory we will look at how Color and the Perception of Color is affected by the source of the light, or the Lamp Type. Anyone who has spent any amount of time working with a mixed package of discharge sources and conventional lights knows that getting them to work together can present significant challenges. Further, the qualities of light (direct vs. indirect or spotlight vs. flood lights) can effect how we perceive the exact same color from the exact same lamp. It is useful to have a basic working knowledge of these ideas so that you can approach your lighting plot from a stronger position.

The Effect of Source.

Most lighting for live performance utilizes Incandescent lights. These are variations on the same bulbs found in any household or workplace. There is some kind of metal filament which is encased in a glass globe. Electricity is passed through the filament and the heat from that is discharged in the form of light. As much advancement as we have seen, these are very simple technologies, and not too far from fire. We burn an object and it creates light and heat. Oldest trick in the lighting book.

Because we are basically operating on the same system as our caveman ancestors, the colors are very similar. These bulbs make a warm soft glow. Our eye is particularly attuned to this range of colors and while the full spectrum of visible light is present in this “White” light, there is a preponderance of light in the Red and Amber range. This makes the light emitted from such bulbs appear “natural” and “looks good” on any range of skin tones.

An alternative to the incandescent bulb is the Discharge Source. A common discharge bulb used in Film, TV, and some live performance is the HMI. Rather than burning a piece (or pieces) of metal, the glass globe is filled with various gasses which, when excited by the introduction of electricity, emit light in rather precise wavelengths. Fluorescent bulbs work this way as well. Depending on the mixture of gasses, the color will be different. Neon is a commonly used gas as are Sodium, Mercury, and others.

How do these work?

Electricity causes a shift in the orbit of electrons around the nucleus of an atom. In these more agitated states, the atoms can absorb some amount of additional electrons. At some point the atom returns to its normal state and the electrons return to their standard orbit. When this happens the extra electrons are released from orbit in the form of photons. The wavelength of the photon (or as our eyes and brain would say, Color) is determined by the type of atom we are dealing with. The Earth’s atmosphere, for example, has a mixture of gasses which, when averaged, produce light in the medium Blue range. As the sunlight filters through the atmosphere, exciting the gasses in our atmosphere, the light emitted from the restored atoms averages out to Blue. Color mixing and physics!

Because the mixture of gasses produce different colors of light, the use of color filters on these lights will produce different effects than when used on incandescent lamps. We commonly see these differences when using Followspots. While the majority of our lighting rig might be incandescent spotlights, the followspots are very likely Xenon, or some other gas. Thus we must balance the color of the spots to blend with the rest of the lighting. The difference in lamp type in these situations is a primary cause of Missing Color Syndrome and a leading need to understand Color Correction. Similar situations arise through the use of many Automated lighting instruments. This is why many will include a CTO option in their color mixing and/or color wheel options.

Not only is the actual color different based on what kind of bulb we have, but the perception of the color can change based on whether the light is direct or indirect, a spot or a flood. Direct light from spotlights are the most common in live performance. Be they ERSs, PARs, Fresnels, or other, all of these lights produce a hard direct light. The light comes, more or less, straight our of the bulb in a concentrated fashion and hits an object. Because of this, the light is seen as being very present. Under certain conditions you can see the geometric shape of the cone of light itself.

Contrast that with floodlights like Mini-10s, Far Cycs, or Mercury Vapor Gym lights, and you see that the quality of light is much softer and more diffuse. We still have the directionality and the hardness, but we lose the geometry. While these can be useful for filling a volume of space efficiently with light, they are not so good for giving that light a clearly defined presence. As the light has less presence so too does our perception of the color. While you might want this effect, it can make colors appear muddy or unclear. You get illumination, but it can be hard to get a real sense of the light itself as an entity.

Taking another step back we have indirect sources like Softlites and Bounce Light. While you can bounce any kind of light off of any kind of surface, typically one uses a spotlight to bounce off a White surface. This is a technique common in Film and TV, but rare in live performance. The quality of light is similar to that of an overcast day. There is illumination, but it is shadowless. The light wraps around and enfolds objects. While it is a beautiful quality of light, one must very carefully consider their color choices here. The light itself is so recessive that getting basic visibility necessitates clear and considered color choices.

While the default choice for most designers is some version of the incandescent spotlight, there is a whole world of options available, each of which provides the designer with myriad opportunities for using Color in new and exciting ways. I would encourage you to explore the whole range of lamps and qualities of light to see how it effects your perception of Color.

Thank you for reading this series. I hope you found it useful.

Did you enjoy this series? Please let me know what you thought in comments.

No discussion of Color or Color Theory on this blog would be complete without an exploration of the color Gray. If I was being truly rigorous and precise it would have been part of the discussion on Saturation and Chroma as Gray is, by definition, non-chromatic light. For personal and pragmatic reasons I chose to place Gray in it’s own section. The subtlety of this range is such that it requires mastery of the other basics before it can really be approached.

I find it amazing to me how many people, when I mention that Gray is my favorite color, tell me it either does not exist or cannot be created with light. In a certain sense this is true. Gray, like White, is a perceptual effect caused by the mixture of all wavelengths of light. However, it is exactly this perceptual effect that I find so rich, varied, and interesting. Curiously these same people who tell me the color does not exist, or can not be created, then go off to start up their computers with apple logos on them and watch as their RGB screens produce a Gray on Gray opening window as it loads the operating system. The inability of many to properly mix Gray, does not deny its existence. Rather, it points out how difficult the color is to achieve.

For a more poetic exploration of Gray read my essay Ten Thousand Shades of Gray. For the purposes of this essay we will be looking at a more systematic approach to utilizing Gray-scale lighting to achieve dramatic effects. Reading my previous essay on Color Mixing, if you do not have much practical experience in that regard, is necessary for understanding the ideas contained in here.

First lets look at Gray from an RGB mix. This is how your computer screen makes Gray. It is how the sticky note upon which I am writing this essay is perceived as Gray by me. Mixing Gray from RGB gives you tremendous control. Just as there are many different Hues of chromatic colors, there are just as many Hues in Gray. You can have a Blue-Gray or a Green-Gray, a Warm-Gray or a Cool-Gray. The subtle distinction and changes in how you mix your Gray, in this case I am imagining a Cyc, make costumes and people pop from that background or recede into it.

All of this control however is deeply time consuming. Just like any precise color mixing (CMY matching Gel colors for example) you have to be patient and clearly look at what you see before you. Mixing a good Gray gets down to adjusting lighting levels by one percent at a time until you reach the final mix. You can not rush this process or the work ends up sloppy and you walk away saying things like “Gray can not be mixed with theatrical lights.”

Not only is the work inherently time consuming but the focus must be precise. It is virtually impossible to do work in a Gray scale on a Cyc without a boucedrop. The light must be even enough that the edges of the color mixing are totally imperceptible. While this is true for all color mixed Cycs, an improperly focused RGB drop in Gray tones, is deadly. Take your time to plan through your drop lighting. Take your time to focus. Take your time to mix the colors. When you have taken the time to properly think through all of this the results will be truly satisfying.

Strict RGB (G250, L090, R80 for example) is one way to achieve these effects. But there are other ranges of colors that can be used. CTBs from about 1/2 CTB to double CTB work quite well. Similar colors like L161 can also be used to good effect. A warm CTB like R3202 can mix well with a color like L161 to create a nice range of cool and warm Gray. Add in a little CLR or Lavender and you can easily mix a wide range of Gray. While your options will be much more limited, you gain the benefit of saving a lot of time mixing the colors as they naturally fall into a Gray palette from the beginning.

Lavenders, mentioned above, can be useful. So too can pale Cyan, especially if you want to cast a more Dominant quality to the light. Cyan can be a wonderful option when used in a palette of dominant blues. However it runs the risk of appearing too chromatic against more recessive colors. Specifically recessive Blues. One must be very attentive to the color choices made when working in Grey or else you simply end up with an unsaturated palette. While that too can be engaging, if it is not the intent, then it is not right.

Let us now return to the Woman-in-a-Red-Dress. While we decided last week to have the entire stage go Red on her entrance, the director thought the move was too blunt. She would prefer to have the woman set against the environment in a striking way. Here is a perfect opportunity for Gray. We light the scene in cool Gray tones throughout. Then, when the Woman-in-a-Red-Dress enters we do a slight shift on the Cyc to increase the Green a point or two. We use our L202 Backlight and R3202 Frontlight for the scene. The effect is one where the complementary colors of Green(er) Cyc and Cool(er) Backlight separate the dress from the rest of the environment. The warm(er) Frontlight helps to pull the dress out even more. This will give us precisely the effect our director wants. A brilliantly illuminated figure which appears to stand outside the rest of the action and an otherwise unified space.

This essay up to now has assumed you were using incandescent lights with color filters to create your Gray environment. However, there is an entire world of lighting beyond those bulbs with incandescing filaments. Many discharge sources work very well to create Gray worlds. Metal Halides and HMIs are a prime example. HMI is daylight and Metal Halide is in that family but pushed towards Green. Fluorescent tubes can be an exciting way to explore Gray. Mercury Vapor lights come close but run the risk of being too Green. They can be amazing in the right balance, but you should use them wisely.

The world of Gray is an amazing, and often underutilized, tool in the lighting designer’s tool kit. While it takes a large degree of discipline, dedication, and rigor, the payoff can be astounding. I encourage you to explore this world and the full richness it provides just as you would more chromatic color ideas.

I hope you found this useful. Please take any new ideas and start experimenting. In my last post for this series I will be exploring The Effect of Lamp Type on Color. Stay tuned.

Was this useful to you? Please let me know what you thought in comments. Or leave any questions you may have and I (or other commenters) would be happy to answer.

From our discussions of Hue we learned the basic properties of what the human eye perceives as color. In later essays we looked at how some of these principals might be applied in practical theatrical settings. Until now we have left out one of the most fun parts of working with color. Color Mixing.

Color Mixing is where we really get to test our knowledge of light and color and see what we know. We have already done some mixing through our exploration of Missing Color Syndrome but that has all been reactionary. We were trying to solve problems, not create environments. Now we will look at color and color mixing as a proactive tool in the designer’s tool kit.

As we recall from our basic color wheel there are three Primary Colors of light; Red, Green, and Blue. Those can then be mixed into the three Secondary Colors of light; Magenta, Cyan, and Amber. Obviously by varying the amount of each color, or mixing in slight amounts of the third Primary you can get the full range of possible Hues out of these three colors. Needless to say, you need not limit yourself to six heavily saturated Hues. You can see from the image on the left the basic principals of Additive Color Mixing with light. It is called “additive” because we might take a Red light and ADD Green to it to make Yellow.

Wait. What?!?!

For those new to mixing light and color this can take some time to wrap your head around but this is how the process works. Red+Green=Yellow. Green+Blue=Cyan. Blue+Red=Magenta. All but the first make logical sense to a brain trained to understand colors in terms of pigments. But we must unlearn that knowledge if we are to truly embrace the power of color.

So Additive Color Mixing comes about when we have two or more Hues mixing together to create a third Hue. This has traditionally been the most common form of color mixing in live performance. However, with the advent of Automated Lighting we have seen a radical shift towards a second method for mixing colors. That is Subtractive Color Mixing.

In order to fully understand subtractive color mixing we need to back up a moment and review. What the human eye perceives as White light is really just the phenomenon of the eye seeing a roughly even distribution of all the colors in the visible spectrum. With that in mind let us look at a typical lightbulb. When the light is on, it emits light across the full spectrum of visible light. If we put a Red (say G250) color filter in front of the light we are not “turning the light Red.” Rather, what we are doing is blocking off, or filtering out, every wavelength of light except those in the Red range.

Now Subtractive Color Mixing gets a little complex, for those new to it please bear with me, the pay off is definitely worth it. When dealing with Subtractive Color Mixing we actually need to invert our understanding of Primary and Secondary Colors. If Red, Green, and Blue are our Primary Colors for Additive Mixing, then Cyan, Yellow, and Magenta are our Primary Colors for Subtractive Mixing. That’s three different sets of Primary and Secondary Colors (when we include the Red, Blue, Yellow of pigments) we have to keep in our brain.

Confused yet?

Subtractive Color Mixing actually subtracts in two ways. First is the method described above where it subtracts all the wavelengths NOT in the color filter. So when we put a Magenta filter in front of a light we are removing all the wave lengths that are not Magenta. Now, remember that Magenta is comprised of Red and Blue. So when we put that filter up it is as though we were using a Red and Blue filter together. If we want to make Red we need to get rid of the Blue.

How do we do this?

If we recall our Primary Color Wheel for light we remember that Blue and Yellow are opposite colors. By adding Yellow to the Magenta we are in essence canceling out the Blue and leaving us with Red. If an algebra equation would help, we are trying to solve M+Y=??? We know that Y=(-B) and M=(B+R) so the equation could be rewritten (B+R)+(-B) or B+R-B=R. Clearly we don’t need to go back to High School Algebra to understand color, but it can help to wrap your brain around the processes involved in Subtractive Color Mixing when first encountering these ideas.

Many Automated Lighting systems utilize Subtractive Color Mixing in their color functions in order to give the designer a full range of colors to work with in their projects. I would like to explore two commonly used accessories. The first is the Wybron CXI and the second is the Morpheus Color Fader. Both of these devices use Subtractive Color Mixing (known in the industry and CMY Color Mixing). Wybron’s technology uses two strings, one with various saturations of Cyan and Magenta, the other with various saturations of Magenta and Yellow. Morpheus uses three strings of color. One each for Cyan, Magenta, and Yellow. The strings range in an even transition from Clear to full saturation.

While the Wybron will give you 432 colors, the Morpheus will give you millions of color options and a degree of precision not available with the Wybron units. Further, because the Wybron units employ discrete pieces of gel strung together one cannot do live color fades without stepping through various unwanted and potentially unpleasant colors in the process. This is the same problem encountered when using a traditional color scroller. The Morpheus technology on the other hand allows for smooth color transitions live on stage. In addition, because it employs three color strings, the designer can vary the speeds at which the different colors crossfade. So if one wanted to fade from Red to Blue, you could have the Yellow fade out faster and the Cyan fade in slower thus passing through Magenta rather than some strange unwanted color.

In a lighting world where advanced automated systems are becoming more and more prevalent, the designer must have an implicit knowledge of these technologies and the color theories underlying them. Even if your work does not typically use color changing technology of this sort, you will inevitably find yourself in situations where you will have to grapple with them. Forewarned is forearmed. Solving problems is a lot more interesting than sitting around trying to decode complex color theory. Especially when the clock is ticking ever closer to opening night.

If we return to our Woman-in-a-red-dress we immediately see the benefits of these theories and their related technologies. Rather than spending tons of time sifting through gel books in the studio and comparing them to the fabric swatches, we might simply point a few of our moving lights, or color changing crosslights, at the Woman-in-a-red-dress on her entrance. From there we can fine tune the color to precisely match the tones of her costume and skin. Having this control is especially nice when the fabric gets dyed a slightly different Hue than we originally planned for.

Perhaps the whole stage goes Red upon her entrance in a bump. Then the rest of the stage does a color fade to our recessive Blue while she walks out and takes control of the scene backlit in Red, with crosslights perfectly matched to her skin tone. Being able to have just the right mix of Yellow and Magenta to make the dress truly shine takes skill, patience, and attention to craft.

Knowing the uses and distinctions between Additive and Subtractive Color Mixing is a powerful practical application of lighting Color Theory. In later posts I will be exploring Gray and The Effect of Lamp Type.

I hope you found this useful. Please take any new ideas and start experimenting. We will continue to build on these concepts throughout this series. Stay tuned.

Was this useful to you? Please let me know what you thought in comments. Or leave any questions you may have and I (or other commenters) would be happy to answer.