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Color media in lighting design
The use of color is one of the most noticeable defining elements of any lighting design. For many designers, color is the most personal of elements, and often times not only defines the design, but the personal style of the designer. Some designers prefer a very saturated palette, with deep reds and purples. Other designers are able to harness the subtlety of white light in such a way that tints gently pull the audience along the path of the storytelling. As a beginning designer, you may be overwhelmed by the sheer number of choices in color, and are not really sure exactly how or why to choose one shade of blue than another that seems almost the same. But as you experiment and understand more fully how color can affect the storytelling, it will become an invaluable partner in your design work.
Gel
Most modern theatrical lighting inventories are populated with conventional lighting fixtures which utilize a tungsten-halogen lamp. The most common way to provide color for these 'white-light' sources is probably one that you're already familiar with: the use of colored gel. The designer chooses what color the light wants to be, and the electrician cuts the gel to the proper size, places it in a frame which fits into a slot next to the lens of the instrument. When the light is turned on, the gel filters out much of the spectrum of light, leaving only the desired color to be cast on the stage. See the color theory section for more of the science behind subtractive color mixing.
Several manufacturers make lighting gel, but the most common are Rosco, GAM (a subsidiary of Rosco) and Lee. The newest kid on the block is Apollo, and they are gaining more market share as time goes by. To choose gel colors, the designer uses a small book of swatches to compare colors. These books have lots of information about each of the colors, including transmission factor (how much of the light passes through, and how much is blocked by the gel), as well as specific information about the amount of each part of the visible spectrum. Again, much more information is available on the color theory page.
Gel is purchased in sheets (approximately 20" x 24", depending on the manufacturer) or rolls. The electricians then cut down the gels to the proper sizes for the lights in your inventory (see chart below), and then installs the framed color into the instruments.
Several manufacturers make lighting gel, but the most common are Rosco, GAM (a subsidiary of Rosco) and Lee. The newest kid on the block is Apollo, and they are gaining more market share as time goes by. To choose gel colors, the designer uses a small book of swatches to compare colors. These books have lots of information about each of the colors, including transmission factor (how much of the light passes through, and how much is blocked by the gel), as well as specific information about the amount of each part of the visible spectrum. Again, much more information is available on the color theory page.
Gel is purchased in sheets (approximately 20" x 24", depending on the manufacturer) or rolls. The electricians then cut down the gels to the proper sizes for the lights in your inventory (see chart below), and then installs the framed color into the instruments.
dichroic glassI will touch briefly on another type of color media: dichroic glass filters. These are much less common for the theatrical lighting designer when working with conventional lighting fixtures because they are much more expensive and there are fewer colors than available in gel. However they do last much longer, and therefore are very common in outdoor permanent architectural applications.
You will, however, come across dichroic filters when dealing with automated fixtures. The color wheels on moving lights use dichroic glass rather than traditional gel, as do some color changing accessories such as the Seachanger line. Here's some more information about dichroic glass filters from Rosco |
Gel Sizes for some common fixture types
Altman 360Q: 7 1/2" x 7 1/2" Source 4, Altman Shakespeare: 6 1/4" x 6 1/4" Source 4 Zoom, Altman Shakespeare Zoom: 7 1/2" x 7 1/2" PAR64: 10" x 10" |
Color Correction
As discussed in the Color Theory section, so-called 'white' light can have a huge variation in hue due to color temperature. Lower color temperature light sources (like candlelight or incandescent) are 'yellower' while higher color temperature sources (like fluorescent, arc sources or sunlight) is 'bluer'. The lighting gel manufacturers have developed whole systems of color correction filters to adjust the color temperatures of different types of light sources. These filters were initially developed for film and video, because cameras are calibrated through color temperature. Having several different light sources with different color temperatures tend to throw the poor cameras into hysterics. By adding a color temperature filter, a high temperature arc source can be made to blend more seamlessly into a rig full of tungsten sources.
One very common usage of color correction is in moving lights. Many of these fixtures use an arc lamp which burns much cooler (but also brighter) than the traditional tungsten/halogen lamps of conventional instruments. As a result, it is sometimes difficult to blend these different types of fixtures in the same lighting rig. Some of these moving lights, within the color mechanisms, have a filter labeled CTO, which is a color correction filter. CTO stands for Color Temperature Orange, and when activated, it adjusts the color from the high 'blue' color temperature to a lower temperature 'orange' look that mixes better with tungsten sources.
However, while these filters are specifically designed to simply adjust the color temperature for the camera eye, they can be used very effectively to tint systems of light in theatrical lighting designs. The Lee CTS (Color Temperature Straw) color corrections- L441, 442, 443 and 444- are my own go-to preference for a very natural looking amber tint for front light. These tend to give a natural warmness to faces, without robbing the color from costumes. Many designers lean heavily on L201 (Full CTB- Color Temperature Blue) as a cool tint, though my own personal taste tends to feel that it is a little too green. As you experiment with color, you will find your own preferences. |
Some Color Correction filters use initials:
CTO: Color Temperature Orange CTS: Color Temperature Straw (less red than Orange) CTB: Color Temperature Blue Others add to or filter out particular wavelengths and are named as such: R3315: 1/2 Plusgreen R3314: 1/4 Minusgreen The "1/4" or is a 'quarter stop' and is related to photography exposure. I don't understand the nomenclature fully- go read a photography text. For our purposes, 1/4 is less saturated than 3/4 or full. |
Neutral density
In each of the gel books, you will find a few colors that appear to be 'gray' gels (such as R97 and R98). The inexperienced designer might choose these gels to light a cyc to create a gray, overcast sky. Unfortunately this is a mistake, because there is no such thing as gray light. These gels are actually colorless, but block a certain percentage of the white light more or less evenly across the spectrum, therefore acting not as a 'color' device, but as an 'intensity' device. These are commonly used on television and film sets, where it is common for the lights to all be on at full all the time. If a light needs to be dimmer for a shot, rather than using a control console, a sheet of neutral density is placed in front of the light source so that the color temperature stays the same.
Theatrical tungsten lamps change color temperature as they get dimmer. As the percentage is decreased towards 0% the lamp gets 'yellower', and because of color mixing, sometimes this affects the color that is presented on stage. If the designer discovers in tech that a system of blue lights is being run at 25 or 30% for much of the show, and it is reading too green (because the lamp at this level is very yellow), it might be advisable to add neutral density to the gel frame, allowing the lamp to burn closer to 50 or 60%, which will make the color read less green, without affecting the intensity on stage. |