A green screen is a brilliant tool that can transport you from a studio in a dodgy area of a grey city to a beach paradise without so much as having to think about booking a plane ticket. However, it’s absolutely critical that you get your green screen lighting setup right, or you’re going to make your life far more difficult than it needs to be, which is definitely not what you want.
To help you keep your budget down and not have to worry about location shooting or how to film in outer space, here’s your start-to-finish guide to green screen lighting.
First, you need to lay the groundwork with your green screen. The fabric needs to be pulled as tight as you can manage to ensure that it is smooth and wrinkle-free. Any lines or wrinkles on the green screen will show up and cast shadows, making it much harder to key out. As well as being crease-free, it needs to be clean, too. Dirty marks will give you a headache in post.
Remember that your subject and your green screen are not really part of the same scene, which means that they need to be lit separately. It might help you to light your subject first and then think about your green screen lighting setup.
Lighting your subject
Keeping a distance between your subject and the green screen is extremely important. This helps prevent green reflections from landing on your subject and light spills and shadows from affecting the green background. Any green splashes that appear on your subject will make the task of keying out that much harder, and shadows cast by your subjects onto the green screen will be a pain as well. By putting in some distance, you help yourself.
To emphasize the separation between your subject and the green screen, use a backlight that you’ve gelled with a minus-green, or magenta, gel. The backlight creates space between the subject and the background. The gel will help counterbalance any green light that might reflect or spill off the green screen and make the task of keying out more difficult than it needs to be.
There are all sorts of light modifiers available that will assist you in lighting your subject and scene precisely and without risking light spills or shadows landing on the green screen. For example, grids help to light a subject evenly without too much spill; flags block off light completely; snoots send light just where you want it, and gels help with video color correction. We have an entire article dedicated to light modifiers, so head there for more guidance.
We’ve already mentioned that you need to light the subject and the green screen separately, but you also need to light the subject for the scene that they are meant to be featured in, not where you’re actually shooting it! If it’s a night scene, think about blue lighting. If it’s a beach scene, light them for that.
How to get the best lighting for your green screen
Consistency is the key to effective green screen lighting.
What you are looking for with green screen lighting is soft, even light, without any hotspots or shadows. The exposure needs to be perfect, too. Hotspots and shadows are hard to key out, and if the exposure varies from one side of the background to the other, it will be tough to work with in post-production. You’re aiming for an evenly lit, universal shade of green.
When using multiple light sources for your green screen lighting, ensure that the actual lights are the same make and model, with the same settings. Using different light types will open you up to too many discrepancies, from exposure to temperature, that might be hard to correct. Keep the green screen lights the same, and you help keep things consistent.
The foundation for good green screen lighting is using big, soft lights. Nothing hard! As a starting point, think about using two large softboxes. Position them a few meters in front of the green screen and at a 45-degree angle to the background. Using second diffusers between the softboxes and the background will really help soften the light and make it as even as possible. The critical point will be where the lights overlap in the background. Be sure to check carefully for any hotspots and use a modifier if you need to.
It’s important that your green screen is properly exposed because you definitely do not want to be trying to fix anything in post, but some people recommend ever-so-slightly under-exposing your green screen when compared to your subject.
It really should go without saying, but we will say it anyway for completeness: nothing in your scene should be green. You don’t want your subjects wearing anything green, whether that’s clothes, jewelry or accessories, and neither should any props be green. Make sure to check for reflections from things like spectacles and watches that can show up as green, too.
If you can keep the green screen itself slightly out-of-focus when you’re shooting, that can help even out any marks or shadows on it. This will make it far easier to key out.
By using a fast shutter speed when filming, you will minimize motion blur in your scene. Even if there isn’t very much movement in the scene, dealing with flyaway hair can be tricky, which means that doing what you can to counteract it will help you out in post-production.
Before you start filming, it’s an excellent idea to go through a dry run of the entire scene. This way, you can be sure that any movements aren’t casting unexpected shadows, that you don’t need more space between your subject and the background, or that there aren’t any random flashes of green that need to be eliminated. Getting halfway through filming before realizing that a step to the left is casting a shadow where you don’t want one is very frustrating!
For a little bit of inspiration, take a look at this Artlist behind-the-scenes video that made use of a green screen.