Chroma Key Technology
Before the advent of Chroma key technology – also known as green screen technology – photographers had to travel to the location they wished to capture. If you needed photos of a model on the beach in Maui, that’s where you went. However with green screen technology almost any location or background can be keyed into an image without ever leaving the studio.
With such a powerful technology so readily available, there’s no reason not to incorporate it into your skill set. But first you’ll need to know how the process works. The good news is that it’s straightforward especially if you’re already familiar with standard lighting techniques. It all starts with properly illuminating the green screen itself.
Preliminary Steps to Lighting a Green Screen
Choose Your Backdrop
Before setting up your green screen you’ll of course need to choose one. Consider the options for your application and make sure to get a trusted brand. Savage Universal makes a variety of excellent green screens to fit everything from an on-location portrait session to an in-studio group shot and more.
Just like standard backdrops, green screens come in vinyl, cloth, and seamless paper. The Chroma Green Vinyl Backdrop gives studio photographers a durable, non-reflective surface that stays wrinkle-free. Also available is a Chroma Green Solid Muslin Backdrop that is non-reflective and offers the versatility of 100% cotton cloth. Tech Green Seamless Paper makes sense for photographers looking for a flat, crisp background free of glare and the convenience of seamless paper. Make sure you have a backdrop stand sturdy enough to support any type of backdrop.
See more: How to Choose a Green Screen Backdrop
If working on location, a chroma key collapsible backdrop is a great choice. This collapsible screen made from non-reflective cotton makes it possible to quickly set up almost anywhere, especially when used with the available 8-foot support stand. Because chroma key technology works with not only green but blue screens also, the collapsible backdrop dedicates one side to green and the other side to blue for ultimate versatility.
See more: Green Screens vs. Blue Screens
Now let’s look at how to illuminate your green screen so you can begin putting your creativity to work.
How to Light a Green Screen
Hang the Backdrop
The first step in setting up your green screen is hanging it properly. The green screen must be as flat and wrinkle-free as possible in order to easily allow the background color to be keyed out. Any imperfections in the surface can cause problems in post-production. If using a muslin green screen, you’ll want to clip and stretch it until it becomes nice and flat. If using vinyl or seamless paper green screens, proper hanging with a support stand will do the trick.
Light the Backdrop
Once the green screen is placed, you’ll want to illuminate it which will take some trial and error. The goal is to make sure the screen is evenly lit with no hot or dark spots. It’s also important to avoid creating shadows on the green screen unless this is desirable in the final image. For this reason you’ll want to light your subject separately from the green screen while also placing your subject as far in front of it as possible in order to eliminate or minimize any shadows.
Proper camera exposure is also something to keep in mind at this point. Underexposing a colored backdrop can make for noisy images, so the green screen must be bright enough to allow the camera to make a bright and saturated image. Yet overexposing a green screen can produce too many unwanted green reflections onto the subject, so don’t overdo it.
Choose Your Lighting
It doesn’t matter what type of lights you’re using as long as you use the same type of lights (fluorescent, tungsten, LED) to avoid producing different hues across the green screen. Savage makes studio lights that work well for lighting green screens, including their 500W and 1000W Quartz Light Kits, each of which contains three tungsten lamps. Savage’s collection of continuous fluorescent lights come in a variety of configurations that can evenly light a green screen.
Position Your Lighting
Now that you have your lights ready, set up the first two as side lights pointing toward the green screen from about a 45-degree angle, and about six feet away, on either side. Again the goal is even lighting, so play around with the angles and distances until you can achieve a light value that’s the same across the entire green screen. If needed, try diffusing paper to help even out your light source. You may wish to add another light, perhaps from below or above, if you cannot get even lighting from two side lights. One common method is to place a light pointing at the green screen onto the floor behind the subject.
You’ll want to light your subject as you normally would, while paying attention to any unwanted shadows cast upon the green screen. This will require more adjustments but with experimentation you’ll be able to find a happy medium between your subject and green screen lighting.
Once you’ve got everything set the fun can begin. With a little practice and repetition you’ll be able to quickly light a green screen no matter what the situation calls for.