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Theatre Lighting Design: A 7-part Hub Series -- Part 3: Color Theory and Use of Patterns
Hub Series Table of Contents
Playing with color with light on stage is possibly the most fun aspect of design. This is where the designer becomes a sort of intangible painter with the stage and set as the canvas. In part 3 of the series, we will be discussing the various aspects of color of light, the physics behind it, the two mixing techniques, amber shift, and what to watch out for (not necessarily in that order). For those of you who are painters, the process is not dissimilar. However, because the primaries are different, there are some things to keep in mind. And for those who are computer graphics designers, you will already be more familiar with the mixing of light color as the principle is the same; there are just a couple things of which to be aware when designing in the light world as opposed to on the screen.
The way we alter the light's color in theatre is with a piece of plastic that goes in the front of the instrument. This piece of plastic is known as a gel, so named because they used to be made out of gelatin. The name stuck throughout the evolution of the accessory. While you can still find glass gels as well, the industry has pretty much moved over to thin, pliable plastic. The three main companies who produce gels (and patterns) are Rosco (my primary source), Lee, and Gam. Between these three companies, there are thousands of varying colors and shades available and are often labeled by number with the company prefix. For example, R60, R02, L202, G57, etc. As touched on in the previous article (Part 2), be aware that the darker the gel, the faster it will burn through. As it filters out the colors of the spectrum, that light has nowhere to go and the heat is trapped within the gel. One should be aware that 'white light' as we know it often slides to the yellow or blue side of the spectrum (think daylight... which is actually bluish). I hope the following gives you a new perspective on light and color.
Color Primaries and Secondaries
As we are taught in elementary school, the three primary colors are Red, Blue, and Yellow with the secondaries of Purple, Green, and Orange. While this is true with pigment, it is not true with light. Due to the fact that pigment color is just a reflection of light and I am an arrogant lighting designer, I tend to call lighting primaries “true primaries”. This is not an official term. It's just something I use to rile up scenic painters.
The three primaries in light are Red, Green, and Blue. These three colors can be mixed at varying levels to create any other color light desired (as long as you have the true primary (official meaning) of each color. All three can be mixed to create white light. The lighting secondaries are not “teal”, “orange”, or “Purple.” The secondaries are, in fact, Cyan, Amber, and Magenta. If you notice, yellow is not even in the list. In the world of light, yellow is an intensity of amber. By mixing red and green at the right levels, you will end up with yellow. The way to get each of the secondaries is as follows:
Red + Blue = Magenta
Red + Green = Amber
Blue + Green = Cyan
Each primary has an opposite secondary (made more clear in the diagram). Green's opposite is magenta (because there is no green involved), blue's opposite is amber, etc. The blue will be used more often in theatre lighting to filter out amber shift (more below).
It is very important to note the difference in primaries between light and pigment; not only for the sake of mixing light, but because your job as a designer is to light a painted set, dyed fabric, and various skin tones.
Color mixing is the act of putting two or more colors together to create a different color. Simple, right? In lighting, there are 2 methods of color mixing and both are used often. The two methods are additive and subtractive mixing.
Subtractive mixing is where you literally subtract the colors of the spectrum you don't want in the light from the light beam. This is accomplished through use of the gels. If you have a blue gel in place, it blocks all colors of the spectrum except that given frequency of blue, allowing the blue to pass through to the destination.
Subtractive mixing is also often used to clean up “amber shift”. Though most modern instruments have minimized amber shift through their construction and materials used, it does still exist and is very noticeable on older instruments. Amber shift is what happens to light color as you reduce the level of the light. With a pure white light, if you dim the power, it begins to move to amber. This is noticeable at home if you have a dimmer on your overhead lights. Turn out all other lights and slowly turn the knob (or slide the slider) to dim the focal light. Watch the room around you turn more and more amber as you lower the intensity of the light. A blue gel (usually what's called a “no color blue”) with low saturation will filter out this amber shift returning it to white (also called color correcting). Be aware, however, that when the light is at full intensity, it will have a very subtle blue tone to it.
Additive mixing is what you're probably more familiar with. It's how a painter mixes paint on the palette. This is accomplished in lighting by taking two differing colors and then mixing them at their destination. So, for example, if you shine a blue light (made blue by subtractive mixing) and a green light (made green by subtractive mixing) and shine them both on the same spot on the cyc, you will get cyan.
So why mix in this manner as opposed to just using one light with the desired color gel? There are a few reasons. The most common reason is effect. To use the same pool of light we just shone on the cyc, imagine pulling each light slightly off center of the other one. Now you have a very nice green that blends into the cyan that blends into the blue. This is often a desired look on actors as well (different colors, but same principle) where the designer wants the actor in white (for example), but the surrounding area in a more colorful palette. When designing for stage, for the majority of plays, there is a “warm side” and a “cool side”. Remember when I said each primary has an opposite secondary? The opposite secondary is whatever color will make white when blended with the primary. So in the case of warm/cool, what is commonly practiced is the warm side being an amber and the cool side being a blue. This effects the actor in that the warm side of the face will be amber, the cool side will be blue, and the middle (or portion of the face facing the audience) will be lit with white light. This allows for better visibility while maintaining depth.
While I will touch on angles a bit more when we get to the paperwork and hang/focus portions of the series, it is important to mention it here as well. You rarely want a front on light. The effect of front on light is a 'wash out' of the actor and everything becomes flat to the audience. You typically (though not always) want 45º to each side of front and 45º up of two contrasting colors. They do not need to mix to white, but you want something that will allow for the depth and three-dimensionality that is produced from this method.
If you ever watch a dance recital that is well lit, you will notice very contrasting colors, usually used as side light (coming directly from the side). One of my favorite combinations for this is a saturated green from one side and saturated magenta from the other.
NOTE: Color saturation is simply a term to describe the distance from white any given color is. For example, if you have red paint and pink paint on a palette, as you add more red to the pink, it becomes more saturated.
Additive mixing is how the cyc changes brilliant colors smoothly and elegantly and how it blends to make a realistic sky. Cyc lights (see part 2) have 3 or 4 cells that are connected to different dimmers. In these cells, most commonly are red, blue, and green. The lights are focused at just the right distance from and angle to the cyc that it allows for smooth blending of the light, indiscernible to the audience.
Excellent Video on Basic Color Theory
Effect of Light on Pigment
I already touched on this a little bit, but we'll discuss it a tad more here. Because the lighting primaries are different from the pigment primaries, a designer must be very careful; especially if green is being used either in light or in the pigment. In this instance, red plus green does not equal a nice, warm amber. If the set piece or costume is green and the light is red (or vice versa), the resulting color is a muddy, nasty greyish brown and you will have one really angry costume designer (never piss off a costume designer... worst thing you could do). This is why (and I can not stress this enough) production meetings are very important and why it is extremely important for the designers to discuss their color palettes with each other. There is nothing worse than having a great color palette only to get to tech week and find out that either you or the other designer has to change (and for the record, it's always the lighting designer who has to change). Now, if that's the look you're going for, then all designers should still be on the same page and know it before hand. And keep in mind that not all reds and greens will react this way. It's dependent on saturation and shade and any ambient light as well.
You can also use this technique to your advantage. If the costume is a light lavender (for example), and you place a bit of blue light onto it, it will really make that costume pop from its surroundings. Be careful with this, however, because the audience's eyes will be drawn to the stunning costume so unless that's what you want, I wouldn't recommend it.
There is another point where you really want to be careful using green light (note that green light can be awesome to use when appropriate, but is also a bane of a designer due to the fact that it just doesn't like pigment – you have to know when and how to use it). If the actor has dark skin and it's not a play about zombies, please don't use green light. Dark skin plus green light equals sick, dead, zombie-like effect. It can be used in small amounts and with other ambient lights, but if your goal is to have a green special for whatever reason and you want the actor to look healthy, I wish you the best of luck. The effect also happens on all skin complexions, but is extremely noticeable on darker skin. A light green light is very useful (no matter the complexion) when the actor is supposed to look sick. However, you have to be careful and pay attention to the blocking to make sure that light doesn't bleed onto the other actors.
Patterns and Their Use
The most common patterning procedure is simply shutter cuts. In an ERS, there are four shutters that can be pushed in, pulled out, angled, etc. to give a specific shape to the light pool, but it only effects the outer edge of the light. Gobos, however, allow the designer to effect the inner portion of the light pool. These are what will henceforth be called 'patterns' for the sake of consistency within the article. I'm not gonna lie. Every designer loves to use patterns when they get the chance. But they can be difficult to focus and to maintain. Many patterns, such as what are called 'break ups' (they're just random patterns used to cast random shadows on the set – commonly used for apparent shadows of leaves) are easy. Those, you can usually just throw in the instrument, point, focus, done. However, there are as many patterns as there are ideas for their use. From custom letters to flames to cityscapes, and beyond. These take a little more 'fiddling' as you want to make sure they line up perfectly with the desired location on the stage.
There are a few types of patterns from the steel gobos (see part 2) to glass to colored glass. Your standard steel gobos are just that. They are little discs of thin steel that have had the desired pattern cut into them. The light goes through the pattern and the uncut portion shadows the remaining light beam (as mentioned in part one, we're designing shadows). These are the most commonly used and once in place (all gobos are inserted into the gate of the instrument), a designer can still color it with gel on the front of the light.
Glass gobos are single color (usually white) transparent gobos made out of glass. The effect is the same as steel gobos, but depending on how they are etched, you can get varying degrees of diffusion.
Colored glass is the grand daddy of gobos. Where with a steel or glass gobo, you can put a colored filter in front of the instrument, with colored glass, you don't need to. The colored glass gobos can have the patterns colored on the gobo itself, and can contain numerous colors to give a realistic effect to whatever pattern being cast. There are some that represent autumn trees where the leaves, themselves, are orange, yellow, red, and even contain the brownish veins within the leaf. As you can imagine, these gobos are quite expensive but the results can be absolutely stunning.
There is actually a powered accessory that is pretty fun to use called a “Twin Spin.” A Twin Spin is a device into which the designer places two gobos (usually break ups). The device with the gobos is then placed into the instrument and plugged into a dimmer. Once the device has power, the gobos spin in opposing directions. When breakups set to a medium-sharp focus are used, the effect is that of water reflection (think of ripples in a swimming pool reflecting onto the house on a summer day). The speed of the 'ripples' is dictated by the amount of power to the device. The more intensity, the faster the spin.
Since we are only discussing standard lighting instruments in this series, the only instruments that can use gobos are ERSes. The size of the gobo depends on the instrument make and model (see part 2). The purposes of using patterns can vary. As stated, the most common used are leaf break ups, however they can be used to cast a shadow from a window frame (or the appearance thereof), full tree shadows, as previously mentioned letters and logos, flames, distant cityscape on the cyc, etc.
There is a lot more to both coloring and patterning light. One thing I didn't talk about was color scrollers. I don't consider them 'standard lighting instruments' and therefore, didn't include them. But they are fun to play with and are worthy of mention. Please feel free to add or comment or if you have questions, let me know in the comments section below.