In this video, learn what to do with green screen video after you've shot it.
- We covered setting up and shooting on a green screen in an earlier chapter. It's now time to take a look at what you can do once you get that footage into HitFilm. Don't worry if you don't have your own green screen clips, because you can download some to play around with. Here I am in HitFilm, with a green screen video imported into the media panel. I'll drop that video onto the timeline. The entire point of shooting on green screen is that it makes it easy to cut out your subject. Instead of you having to manually cut around somebody or something, instead, you get the computer to do it for you.
By shooting against a green screen, the computer is given an easily-recognizable background to isolate. So far in the course, we've only used the effects panel to find transitions during editing. This time around, we're going to have a go at some real visual effects. Find the keying folder in the effects panel and open it up. Inside, you'll find an effect called color difference key. As a note, remember that you can type into the search box at the top of the effects listing, to find specific items.
You don't even need to know the technical name. So if I search for green screen, it'll still find the color difference key. This is often quicker than browsing through the folders. I'm going to drag the effect onto the green screen clip on the timeline. Immediately, you can see it having an effect. The black and gray checkerboard pattern is used in HitFilm to represent transparency. So the green screen has already been partly removed. With that clip selected, I can switch to the controls panel and go in to refine the color difference key settings.
Use the little triangle icon to open up the effects settings. Adjusting the min setting affects the sensitivity of the green screen removal. At low values, less green will be removed. On the other hand, go too high and you'll start to punch holes in your foreground subject. To make it easier to see what's going on, activate the view matte option. This shows a grayscale version of the shot, whereby black represents transparent and white represents fully opaque, with any kind of gray representing semi-transparency.
In this mode, it's much easier to see when the background has been properly removed. I'll adjust the min setting until the background has vanished. The gamma setting can be used to further refine the edges, but this won't always be necessary. Once you're happy, deactivate the view matte option, to see the actual result. You should now have a clip with the green screen removed. This is where it becomes important to put the effort into the shoot, because that's where you can ensure that you have a high-quality green screen setup, which, in turn, makes this post-production phase, when you get onto the computer, so much easier.
Sometimes you might need to adjust the max setting as well, just to make sure that your foreground remains nice and solid. If you see any holes, that's the one to adjust. So what can we do with this now? The clip still exists as normal on the timeline. First, I'll click and drag it up with the selection tool, automatically creating a new track and leaving the track underneath empty. I can now put a new background in here, which can be an image or a video. This is actually the foundation for a lot of the visual effects used in big movies and on TV shows.
Watch any behind the scenes footage of a modern production, and you'll see green screen and blue screen showing up on set, all over the place. For your immediate projects, you're most likely to use green screen in the same way it's used in newsrooms and for weather reports, creating a more visually interesting backdrop and making it easy to drop other videos and pieces into the background. One thing to watch out for when shooting on green screen is something called spill. This is when the green light from the green screen reflects onto your subject.
It's almost impossible to see in the original footage, using your naked eye. Take a closer look at this shot by zooming in. You can use the mouse wheel or the viewer scale menu in the corner here. You can see some ugly green spill around the hair. Fortunately, HitFilm has a built-in effect which makes this pretty easy to deal with. Switch back to the effects panel, then search for spill. This will find the spill removal effect. Drag that onto the green screen clip on the timeline. And note how the green spill has pretty much disappeared.
This process of combining multiple layers together is called compositing. What you've just done is a very simple version of the same techniques Hollywood uses to create the blockbusters that you watch at the cinema.
- Getting started with HitFilm Express
- Setting up a camera and lighting
- Making a shooting checklist
- Shooting on a green screen
- Transferring from camera to computer
- Converting video formats
- Importing videos into HitFilm
- Using essential editing techniques
- Using multiple tracks
- Making color corrections
- Working with keyframes and composite shots
- Creating titles and lower-third captions
- Exporting and sharing video