Join Richard Harrington for an in-depth discussion in this video An introduction to keying in Premiere Pro, part of Green Screen Techniques for Video and Photography.
- Now, Photoshop was pretty straightforward, and I think it serves as a great foundation for what comes next. - Now, working with video is very different than working with a still image, and though some of the techniques are similar, it's kind of a whole different ball of wax. - Yeah, I think where the problem comes is that it's such a lower resolution medium. So, when you're dealing with a high quality raw file, you've got tremendous latitude. You could recover the highlights, or bloom them, so you get a nice perfect key. You can get in there and really refine edge detail, and things like clarity, to just pick up those edges, it's perfect.
With a video, because of the way video cameras work, so much information is smashed and thrown away, especially on a DSLR, that it's like you're working with a JPEG quality one photo, when it comes time to do the key. - Absolutely, and not only is the quality worse, because of the compression, but even the size of the image. The highest of hi def televisions are only 1920 by 1080, that's less than two megapixels. - Yeah, that's practically nothing. And you deal with the fact that you don't have to just make a single frame look good, you could be dealing with hundreds, if not thousands of frames, and as the subject moves around.
Come on, move around with me. As they move around, it gets difficult. So we can stop now, we're making him dizzy. (laughs) But as they move around, they turn their head, the light hits differently, they start waving their hands in the green screen space, and you get vibrations, you can get these areas that just don't key very well. So, when it comes to keying video, it's a lot harder than keying photos. And we're going to take a look at a couple of techniques here. There's really sort of two schools of thought. One is, do it in a compositing tool, the other is do it in the editing tool, and what's the logic there? - Well, for a lot of folks, they're uncomfortable with jumping into a, what they call a higher end tool, like After Effects, they're a little afraid.
They may know their editing tool, but they look at After Effects and it's really scary, kind of like the first time somebody ever looks at Photoshop. - Yeah. - Now, once you know Photoshop, it's like I know exactly where everything is. So they like that comfort zone. And a lot of the editing tools out there actually have relatively good keyers built in, but sometimes you really need to take it to the next level, to make that key look good. - Well, I kind of liken it to the Lightroom and Photoshop relationship, which is you could do great processing of images within Lightroom, you know, you don't necessarily need layers, you can get in and do a really good image.
However, at some point if you want to take it to the absolute level, you're going to kick that photo over to Photoshop, and do more with it, and you're going to start to do some extra processing and layering, especially if it was a composite image, because you couldn't just pull that off inside of Lightroom. It's a lot like that in an editing tool. With video editing, you can do some basic keying, but some of the advanced tasks, like blurring, or relighting the scene, just aren't there. But, to make it easier for you, we're going to take a look at a couple of popular video tools, and show you some standard work flows that make keying a lot easier.
With video editing, you can do some basic keying, but some of the advanced tasks, like blurring, or relighting the scene, just aren't there. But, to make it easier for you, we're going to take a look at a couple of popular video tools, and show you some standard work flows that make keying a lot easier. So Alba, before we get into the complex compositing, let's do something that just about anybody can do, and that is key video inside of a non-linear, or video editing tool. - So, we're going to use Premiere Pro, because you probably already have it if you have the Suite, so you might as well go and use that.
Now, the same techniques that we're using in this non-linear editing program, will work in any other non-linear editing program that has a built-in keyer. - What I'm going to do is start by putting the background in first. So, in the Project Panel, I'll just scroll down, find the background, and drag that to Track One. Now, in this case, I'm not going to change my sequence settings. So I'll tell it to keep the existing settings. Up on Track Two, I'll grab my video clip, and put that above.
Now, you'll notice it's a little bit longer. So, if I click on the end, I can pull that back, so it matches the duration. Now, it's pretty straightforward. Let's select the clip here, so it's active, and then I'll click and go to my Effects panel. You can find that from the fly out menu, or use the Window menu and choose Effects. In the search field, type in the word key. Keying is the process of knocking out one color, and making it transparent.
I'm going to use a built-in effect called Ultra Key. And I'll simply drag that and put it onto the top video clip, the green screen shot. If you double click, you'll see it loads into the Source Monitor, and you can go over to the Effect Controls tab, to see it. With the Ultra Keyer effect applied, click the eyedropper for key color, and select the green near the subject's head.
Now, in order to see this, I recommend switching from the Composite view to the Alpha Channel. This will make it easier to see what's happening. The next pop up also has several presets, and you can see that you can use a Relaxed or a more Aggressive method, which starts to clean things up a bit. I'm going to go with a Custom one here, and just start to manually do this. If we take a look at the Matte generation, this is what's generating the matte itself, and there are several controls.
For example, the Highlight controls go after the brighter areas, and the Shadow controls control the darker areas. I want to be careful though, if I drop down too far, you see that it starts to introduce transparency into her hair. So, I'll get it so it looks pretty good for our subject, that works pretty well. And I can now twirl up highlights and shadows. The Tolerance setting is more or less aggressive. So I could increase that a bit, and then work with the overall settings here for some of the clean up.
The next category, Matte clean up, offers several useful options. For example, you can improve the Contrast, for tighter edges, and then simply use the Mid Point to pick up more or less area. That works well, and let's bring up Contrast, and we filled that in pretty nicely. Now, I still have a little bit of a hot spot in the bottom corner there, but you'll notice that you have easy controls here.
For example, I can simply choose Crop, in the Effects tab, and apply that to the video clip. And now easily crop out a little bit from the right, to get rid of a problem area. Let's set the Ultra Key effect back to the Composite image, and have a look. Now, that's looking a lot better. We've got a nice clean key, the edges are looking pretty good, and the finer detail, around the hair, is holding up well.
This allows me to judge the effect. And I'd suggest considering popping into 100 percent, so you can look at those edges. This will help you better judge what's happening. For example, if I look at the Ultra Keyer here, I think I could soften that edge just a little bit. There we go, and you see that that little halo disappears. Plus, the Choke command can be used to erode the edges. Now, don't go too far, or you see that it actually cuts in, and shaves off a whole layer.
But, Choking a little bit, is going to help remove any stray pixels. That looks good around the edges of the hair, that looks clean. Let's drag back through and see the hair at the back, a little too aggressive there. So, playing with the Contrast setting, and the Feather, will soften that. That helps nicely clean things up.
All right, as a reference or initial key, this is looking pretty good in the non-linear editing tool. Remember, you can get better results using a tool like After Effects, but this is doing a nice job. The only thing that I think is left is to really work with Color Correction for foreground and background.
This course was created and produced by Rich Harrington. lynda.com is honored to host this content in our library.
- Why use green screen?
- Using a fabric, Flexfill, or Reflecmedia backdrop
- Lighting the green screen
- Establishing a relationship with the subject
- Shooting handheld
- Shooting with a DSLR
- Using a sync sound workflow
- Processing raw footage
- Creating transparency in Photoshop
- Removing the background
- Adjusting background focus
- Keying in Premiere Pro or After Effects
- Animating the camera
Skill Level Appropriate for all
Q: This course was updated on 03/01/2017. What changed?
A: New videos were added that show how to key out green screen video and match color and exposure for video in Final Cut Pro X.