Now that your green screen footage is shot, you can insert a background plate behind your subject. What is a background plate? What are elements that make for a good background plate? In this video, Richard Harrington discusses what you need to look for when choosing which background plate to use for your green screen footage.
- Now that you've captured the footage of your chroma key, it's time to talk about what goes behind that image. Ideally you're going to need some background plates, and there are many different ways to approach this but let's start by discussing what makes a good background. Ideally a background is just that, a background. You want it to be something that is evocative of what would be behind the subject if they were going to be in that location. Now sometimes backgrounds are photos or video, and other times they're photorealistic 3D renderings.
A strategy though is to make sure that they're not too busy. While a background could be very cluttered, you don't want any gawkers or people walking through the background if they stop and stare into the camera. Rather just normal behind the scenes traffic if you have moving video of people walking through. Additionally, the good background is probably not perfectly in focus. Remember, unless you're trying to really simulate an extremely deep depth of field, you're going to want some defocus to that background.
Now, that defocus can come during post-production or while you're capturing it, and we'll talk about that a little bit later. Other things to think about with the background is lighting. For example, is it lit at a particular time of day? Are you trying to make it look like that time of day for the video production, or are you going to need to change it? A lot of times a raw photo is pretty easy to manipulate, but even a video file can have its color temperature adjusted. Think about the lighting though. Is it meant to be directional? Do you want moody lighting? Is there a certain type of weather condition you're trying to simulate? Is it supposed to look like a bright, clear afternoon day, or early morning mist? All of these things are going to come into play.
Now, sometimes you're going to be shooting your own background plates, and other times you'll be relying upon stock photography services. It doesn't matter as long as you have an idea of what you want. Chances are you could pretty easily create it or find a place to buy it. Other things to think about is, are the colors going to compliment your subject? In the real world, we'd often apply art direction when staging a shot, meaning that we'd take into account peoples' wardrobe and accent colors in the background. Or that the background was dark enough so that the person stood out.
Speaking of colors, you're also going to have to think about skin tones, and the different ethnicities. Some backgrounds may blow out or not be high enough contrast. Think about balancing the person that you're putting in front of the background, and what's needed back there. Depending upon the darkness of their skin tone, you may need to make some choices about how the background is framed or what the subject matter is. All in all, backgrounds are pretty flexible. What you're trying to do is really create something that is going to tell a story.
Now, what's pretty important is that that background matches the angle of the shot. So if it's a really high or low-angle photo, it won't cut together. Or if it has a strong sense of directionality, you might actually have to position your subject ahead of time. This is why I encourage you to think about the backgrounds before you shoot the green screen. But there are several strategies that you can do to manipulate perspective or make adjustments to the photos during post-production, and we'll talk about some of those strategies a little bit later in this course.
Now that you understand what makes a good background, let's go over a few strategies for acquisition.
- Why use green screen?
- Using a fabric, Flexfill, or Reflecmedia backdrop
- Lighting the green screen
- Recording green screen in-camera
- Using a field recorder for green screen
- Capturing a background with a light field camera
- Processing backdrops for green screen
- Keying in Final Cut Pro X, Premiere Pro, and After Effects
- Animating the 3D camera