Green screens – what’s the deal with them?
Firstly, there are a couple of key points about the green screen itself you should know before using/booking/buying a green screen. Number one is the green screen should be large enough to fill your frame. The green screen should also be smooth, you will run into trouble if the green screen has wrinkles or casts shadows, it should be able to reflect light evenly. Lastly, the green screen needs to be bright enough to contrast well with the subject you are filming.
Lighting the green screen is key to achieving good keys in post-production and this can be broken down into two parts. The first is lighting the actual green screen. Your goal should be to light the green screen as evenly as possible using soft light. Soft light sources that cast broader light are important as any variation in light across the screen will read as a gradient and that will lead to problems when keying your screen in post production. Soft boxes are a good tool to employ when wanting to achieve soft light.
The second aspect of lighting to take into consideration is lighting your subject independently. This is important as it will allow you to control shadows and reflections. Shadows from your subject falling onto the green screen background will affect your ability to key your subject. The easiest way to counter this is to make sure your subject is a good distance from the green screen (at least a few feet). If you are tight on space, moving your key light and fill lights slightly to the sides so the shadows fall outside of your frame will help. Reflected spill light from the green screen can cause your subject to have a tinted halo around them which will make your keying look messy as they will have a green tint from an unknown source once you swap out the backgrounds in post. Once again the quickest and easiest way to counter this is to ensure your subject is far enough from the background.
Locking down your tripod is important as any movement from the camera that isn’t tracked exactly with the background replacement will see your subject bouncing around while the background remains still. This is an easy but vitally important problem not to succumb to. So, unless you are using tracking markers on your green screen and are planning on using complicated visual effects compositing software that can match the camera motion perfectly with the digital background you are using, just lock down your tripod and take your hand off it once you are rolling.
If you’re interested in using our green screen studio, or want to talk about your project, just visit our website and get in touch!
WhatsApp us
