A Beginner’s Guide to Color Mixing for Stage Lighting

When selecting light fixtures, there are many different features available. Features that will suit a whole array of different venues and purposes. One of the primary considerations is what kind of color options are best suited for your needs. The ability to create different colors from one fixture is advantageous in many ways. The old way of doing things was to employ the use of colored gels. Light techs would place them in frames, sliding them in front of your conventional lamp bulb. This involved the tedious process of climbing up and changing out the gels for each production. It didn’t allow much flexibility for color switching during a live run. In addition, you had tons of gels taking up space somewhere in your booth. 

While individual gel frames are still used by some, most venues have transitioned to easier and more efficient methods. Most color fixtures today feature built-in color mixing. To understand the way this is achieved it is important to distinguish between the two methods used to mix and change lighting color.

Additive Color Mixing

The first way we can change our light color is through additive color mixing. As the name implies, we take two colored light sources and layer them on top of one another to create our desired color. So, when we take a red light source and a blue light source and combine them we create magenta. We can control the shade by how intense the reds or blues are or the ratio of sources of one over the other. A great example of additive mixing is our televisions. Televisions use pixels of different colors to produce the array of colors we see.

Today, the prevalent use of additive color mixing comes from LED light fixtures. LED fixtures create colors by fading up and down their red, green, blue LEDs. Click here to learn more about RGB Color Mixing. Many LED fixtures include amber, lime, and white LEDs to provide even more color options. For instance, amber LEDs allow you to make more punchy pastel colors that wouldn’t be possible with just RGB LEDs.

Subtractive Color Mixing

On the opposite end of the spectrum (pun intended) you have subtractive color mixing. The subtractive method takes a white light source using all the colors of the spectrum and uses colored filters to block out certain color wavelengths to alter the color of the light. Theaters have long relied on the use of colored “gels”. Named for the gelatin material they were made from, these thin, plastic squares filter unwanted color wavelengths letting through only the desired color. They subtract color from the visible spectrum. Today, color wheels work in the same way but without the hassle of having to climb up a ladder. Color wheels in moving head fixtures are basically a set of gels that you can switch between via DMX. More expensive fixtures allow you to switch out the colors in your color wheel. However, most fixtures give you a fixed set of colors to work with. Some fixtures give you two color wheels, in which you can put two different gels together to mix a different color. However, color mixing with two color wheels considerably limits what you could do compared to color mixing via CMY or RGB LED . 

CMY Color Mixing

Another form of subtractive color mixing is CMY color mixing. Moving head fixtures utilize this method by including a color wheel consisting of dichroic “flags” in the colors; cyan, magenta, and yellow. These are applied in different combinations to achieve the desired colors. For instance, if you want to create red, you combine the magenta and yellow filters at full to filter out the other colors until red is the only color getting through. CMY allows for a much smoother transition of colors than a fixed color wheel would. Also, CMY allows you the flexibility to find a good color match to other fixtures using additive RGB color mixing. However, creating some colors with CMY would limit your fixture’s brightness. For instance, creating red via CMY flags would create a beautiful deep red. But because you are subtracting a lot of light to make that red, your fixture would lose quite a bit of brightness. Many fixtures featuring CMY also include a color wheel. So, you may be able to use the included color wheel to create many of the colors that would lack brightness.

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This illustration will give you a visual example of each of the methods used.

Note how all-on additive color mixing makes white light, while all-on subtractive color mixing makes black. This is a good illustration of these two methods. Additive adds up to white. Subtractive subtracts down to black.

Fixtures

It is worth noting that subtractive color mixing is used primarily for moving head fixtures. When choosing your static wash lights, your main considerations would be what kind of LED fixtures you should get. You would want to consider a range of factors, from beam angle, to quality of components, lumens and wattage, color temperature, and so forth. Colorwise, you would want to consider what kind of LEDs are part of your fixture’s LED Engine. Fixtures that add Warm White LEDs to the standard RGB LEDs allow you to make a much warmer white without compromising brightness. As noted before, the addition of amber LEDs allows for creating punchy pastels that wouldn’t be possible via just RGB LEDs. It is important to note that fixtures with just white LEDs are usually much brighter than color fixtures.

Price

When choosing what color mixing to use in moving head fixtures, the price would be a factor. CMY is a more expensive feature, with CMY fixtures starting at 3,500 and going up way more than that. The most affordable movers would use a single color wheel, with more expensive fixtures adding a second color wheel, and the option to change out the colors in your color wheel. Expensive CMY fixtures will usually include a color wheel as well as being jam-packed with other pro-features. For static wash lights, regardless of price, you will be looking at additive color mixing via LEDs for all the fixtures.

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If you would like help in finding what moving head fixture would be perfect for your needs, please feel free to give us a call at 615-599-1505. Our staff is not on commission, and have no incentive to sell you anything that you may not need. If looking for a static wash to create beautiful color, we would suggest checking out our RGBWW Spatial Wash COBs. If you’d like to take a deeper dive into color mixing and practicals for lighting your production, I recommend checking out this article for some great information.

Thanks for reading!