Special Tools: Green Screen
There is more to green screen than just editing. You need to shoot it properly. There are some courses on that. But the general rule of thumb, and I'm gonna go ahead and jump over to some green screen footage again. I have a before and after, Is to try to make the background be lit as evenly as possible. So that you don't have various shades of green, because when you're removing any color, you're looking at the luminance, you're looking at the saturation, and you're looking at the hue. And the tighter you can make that, the easier it is to separate that one color from everything else. If you are dealing with, and this is not a great one, okay? This is more luminous than that. If I looked at this in Photoshop, and I looked at the RGB, there's definitely different luminance levels. Probably because the luminance is different there's probably different saturation values, perceived saturation. So this is not great, but I'll tell you, I've been given green screen where they don't even care...
about the background. They just think as long as it's green, you can just hit a magic button. So, the tools are better. And as a matter of fact, there are third party plugins that their only job is to give you a cleaner key. A cleaner green screen, and they're amazing. And there's all these parameters you can play with, and they're not that expensive anymore. Maybe $100, which is not that expensive compared to four or five thousand dollars back in the day. But, they can compensate for some of this. But the whole idea is that you want to shoot this a certain way. You wanna make sure the background is as flat as possible, and is evenly lit. I'll give you a couple little tricks on the shooting of that before we get into fixing. So, if I was gonna shoot her, or when I shot her, actually, I did a few things. First of all, I lit the background without her in it. I just wanted to light for the background. As evenly as I could, but not perfectly, because I wanted to use it as a teaching example. Of course I could do it perfect, we all know that, right? Yeah, very modest. So, I did that. And, you can use a light meter. A trick I use to see if the luminance value is consistent, and this is a green background, it's not green lights, is you can turn on zebras, a blink point on some cameras, to where you're at 100 percent of luminance right before you go into losing detail. Well, I open up the aperture until I hit that point of either seeing the zebras, because I've turned them on or they're blinking, and I can see what parts of the background are at 100 percent. So I'm not exposing it for my shot. I'm exposing it to see, oh yeah, my eye can't see that there's a 10 percent difference in the luminous value here, and there, and maybe I need to throw another light there. So that's the key. Nice soft lighting. And I want this to be as smooth as possible. The way I achieve this to be smooth as possible is I want it to be out of focus. So what do I do? I get a long lens and I go as far away from that as possible. Okay, so, she's way back there, I mean the wall is way back there. I'm on the other side of the studio. And I kind of put her in the middle. And I set my depth of field sweet spot to be where she's standing, so it drops off in the background. And I can achieve that through my focal length, and my aperture. And I really use a lot my focal length, because I want to have more options with my aperture. So I might have shot this with a 200 millimeter lens. And also people look good with a 200 millimeter lens, versus a 24. And it also allowed me to get her further away from the green wall. So, I cannot- I can do two things. I can light her independently, and not have it fall onto the background. And also, if she was too close to the green wall, the green, and it still does a little because she's a redhead, it's a real challenge, she has very fine hair, don't want to give you a perfect shot to work with, reflects, and I would see more of it, there might be green bouncing off there onto her clothes. And then when I try to remove the green, I'm gonna get horrible edges. Okay? So, all that forethought should go into it, when shooting it. You don't always have that luxury. But, again, forethought will help when you actually need to execute. And sometimes you don't have the luxury, and you have to really work with fixing stuff. So, that's how it was shot. And now is the easy part. I throw it onto my timeline, and I put it on track two, on video track two, because on video track one, I'm gonna throw some sort of background. Whether it's putting her into a location, or just a nice background wallpaper, or for our purposes, I just created a blue background, from the Generators tab. I said generate a color matte, made it blue. I've already done that. And now I need to do two things. I need to cut her out, by removing anything that's green. And I also need to do some sort of a mask, because if you notice, I didn't need to make the whole background green. It also would be too big of a sheet. This was I think still even a 12, this was a 12 foot wide, but I'm far enough back, that doesn't look like 12 feet. Because I'm gonna use a mask, and say, you know something, I can do this, remove this another way. So, that's the shot. I'm gonna go over here, and the tool that you wanna use is called the Ultra Keyer. Okay, so if you type in Ultra, you'll see that, underneath there Video Effects, Keying, there's something called Ultra Key. And I'm gonna just toss that on the top shot, on her, okay? And now this comes into play. It loads in. I'm under the Control Effects tab. And, the first thing I need to do, is simply tell it what I want to key out. It doesn't by default say I'm gonna key green. Maybe you have a blue background. If she's wearing a green dress, I can't put her on a green background. And technically, you can use this for any color. You can use this even on a graphic, okay? You're just telling Premiere what color you want to remove. So I grab the eyedropper, and I select what I would consider kind of a median area. Not too bright, not too dark, as representative. And, it does it's best job, which is pretty darn fine, of removing the background. We're gonna tweak it. But, even with a click, that's pretty good. Okay? But let's show you how we can even refine that, and what the sliders do. So I did that, and I think it's pretty good. If I go over here, there are some default settings. First one being called Default. But, you can switch it to Relaxed, Aggressive, and then it customizes as soon as you start moving some sliders. But what this will do is, it will try to be either more aggressive in the key, in case it wasn't well lit, but you might start getting kind of that, losing some of the fine hairs, or some of the edging, depending on how aggressive. So, I'm gonna switch between those two, and you can see the result. And I'm gonna switch two different ways. One with the blue background, and also one where you actually just see what the matte is. What I'm actually pulling out. And that's gonna be some switches here. And I'm gonna kind of slide back and forth, because it's easier to see. So, if I go to relaxed ... Let's see if I can do this easier for you. And I'm going to hit Relaxed. And if you notice, some of the background is actually not being keyed out. It's being too gentle. And if I switch over to Aggressive, it gets rid of all that translucent stuff, but I'm starting to lose a little bit of the fine hair. And sometimes if it's run and gun, that's good enough. But, I want to tweak this, and I want you to learn what the sliders do. So the first thing I do, when I'm starting to do this, I'm gonna go back to the default. I'm gonna switch from Composite to Alpha Channel. We've heard that term before. Basically what that means is, the transparency information that I'm using to remove her from the green background. So whatever is solid white, is her. Whatever is solid black, is what we see through, and we see whatever background we've put. Whatever is kind of gray will be translucent. So my goal is to make this as black and white as possible, because then I see everything in the background, and she's solid in the foreground. And a good way to remember what the white does versus what the black does, on one of these mattes, think of the moon. And if I threw a bucket of paint at the moon, whatever was white, the moon, and it hit, that's what I'm gonna see. And then the rest just goes off into space, and that's what's transparent. So this is the content. So what I'm gonna do now, is I'm gonna work with some of these sliders, to make this a more solid black and white image. So let's go ahead and zoom in, and talk about some of those. So, I'm gonna close up some of these ones from the default ones, just so we can focus on exclusively the ones in the Ultra Keyer. And so, switching to the Alpha Channel, I'm gonna open up something called Matte Generation. And you see some things. You see Transparency, Highlight, Shadow interface, as well as the Pedestal, or the luminance factors. So I'm gonna zoom out a little bit, so you can see the result here. And, my recommendation is, to get used to working with this, do the same advice I gave you earlier throughout the course, which is play with the sliders. Be very broad with them. See what they do. You can always reset them. So, as I'm working with the transparency, what this is doing, is this is dealing with, if I leave it like that, she'll be translucent. So my goal is to try to make her solid. And that's the transparency. When I go over to the highlights, that's focusing on, I wanna bring down to make that a solid black. I still have some problems with the top. I may go to the shadows, bring that down. And then go, the tolerance is like my breakpoint. I'm gonna go ahead and bring up my pedestal a little bit. And my goal, and now I've done that, and you just play with this. Let's see if we can make her ... So I'm playing with these things, trying to get this as black and white as possible. Now, it is a little tricky here. I probably would ultimately do another trick. She has green eyes. Okay, so what I would actually do is, I do what's called a holdout matte, or a mask, on another layer. Just to cut her out. Think about in Photoshop, you just kind of remove the eyes to another layer that you don't apply any kind of a filter to. So that's one of the tricks. Now when you get to more complex tools, that have more tools to add to it, you have things where you can really control the inside and the outside as a separate layer, and then the edges, and there's something called spill, but this is all kind of built into one pretty powerful tool. And I played with this, and I probably could have got this a little bit better but, now that I've done that, if I go and switch from alpha to composite, it's a little more solid. I think, that doesn't look solid. Or maybe it's just my blue background. Let me switch to Alpha. It was kind of black. My eyes are playing tricks on me. Let's go ahead and reset this back to our saved layout. So now we can go full screen. Which brings in a dock. Now, there we go. So I'm gonna go ahead, and I'm gonna just reset this back to the defaults. Go back, select it. Maybe I was on Aggressive, there we go. Switch to Matte Generation. Look at the Alpha Channel. I'm gonna actually start here with the shadows, bring the shadow down. If I do that, see if I do the right thing first, I don't have to move everything else. Okay. Pedestal. I actually think that's much better. Let's go see what the Alpha Channel looks like. So this is gonna be a little bit tighter. I won't have lost as much. So, I think that's pretty good. If you want to get really down to the nuance, there might be a little bit of green there, that's reflecting. There is something called a spill, which is also on here. And spill as well as matte cleanup allows you again to work with some of the nuances. And I'll just tell you what some of these things are. So, the Choke slider, and it works very subtly, so you know, you were gonna play with it and see what is it doing. It takes the matte that's created, and it either brings it in a few pixels, or brings it out a few pixels. So sometimes, if you use the choke, you can get a nicer, cleaner key, if you're getting a lot of edging. Or sometimes if you're getting too much, if it's too aggressive, and you're getting kind of like a helmet head, because it's getting ... You might want to loosen that. So that's one thing that you play with. The other thing is softening the edges. And this is again something that we're used to when we're actually creating transparency in Photoshop, is that when you look at, our eye sees the edge of my shirt. It's not really a sharp edge, it kind of blurs. So sometimes when I work with a mask, I actually use the choke and bring it in a few pixels, and then I soften it a few pixels to let it kind of bleed out, and now it's gonna blur into the background without actually seeing that ringing edge. So I choke in a little bit, and then I blur or I soften a little bit. And then you can start looking at the contrast in the midpoint, when you're inside of the Alpha Channel. It helps you sometimes clean up these random areas inside, so you don't necessarily have to throw a holdout matte. And you can kind of see this. A lot of times I'll take this to 200 percent, to really see what's going on. I am not worrying at all about these edges, okay? So that's that area. When you get down to spill, and let me talk about that. What happens when you create a key, and we'll switch back to Composite is, you do have a situation when you have some green coming through, or green reflecting, so that's called spill. And, what I want to do basically is replace the green with something that's more neutral. So, a Spill Suppressor actually kind of puts a little of the opposite side of the color wheel, which is a magenta color, and if you really push this slider, she'll turn magenta, okay. So again, a little goes a long way, but your goal actually is to select that green area with the Spill slider, and then you actually de-saturate it a little bit. So you're not only compensating to make it gray, magenta versus green to bring it down to the center, but in a sense you're de-saturating it, so that you don't see the green edges. If you don't really see them to start with, and remember, you're not necessarily looking for it, the less sliders you play with, probably the better. Okay, I just want to say that. And also, this is challenging. I put her right in front of blue, with a green background and red hair, so you can see it. But if she's standing in front of something that's moving, or something that might even have a little green in the background, you would never know. I do wanna add one aside, when dealing with green screen, and that is, if I was going to attempt to put her into a real environment, and photographers are aware of this as well, because you see bad and good compositing, the whole idea is when I shot this, if I knew where I was gonna put her, I would light her as if she was in that environment. So, if I put her where she's outside of the beach, I would put a really strong key light on her, okay? Because that would be natural. The other thing I would do, is once I did the composite, I'd use my color correction tools, to make sure that her color, and her gamma levels, the black levels within the frame, match the shot that I'm putting her on top of, so it doesn't feel like she's pasted over, so that there's, the colors are balanced. And as a matter of fact, some of the higher end tools literally have matching tools where you grab and you sample the highs, mids, and lows of the background, and the foreground, and then color samples, and it does the best calculation to get those to merge together. Another thing I do, when I cheat, is when I get there, to get it even closer, I then put an adjustment layer on top of everything, and put some sort of maybe like a golden tint, so it kind of hides the fact that the foreground and background were different sources. So there's a lot of tricks. The same ones that you would apply if you're a still photographer, and doing compositing in Photoshop, you're just doing the same thing here in motion, and just hoping that the light's not changing too much in the shot. And so that's the idea with these sliders. It does have a Color Correction option, that if you start tweaking things, you may have screwed up the color balance. I still would probably use this with the lumitry color. This is just Saturation, Hue, and Luminance. But, we're gonna go here. If I play this, that's pretty nice, compared to where it was. And now I'm ready to remove the background, and I'm gonna leverage the fact that there's already a filter on every single clip, called Opacity, okay? These, the Motion, Opacity, and Time Remapping are always there, on every clip. And, even, and I did get this question offline, which was, where do I get to Opacity? And I went through that kind of quickly in an earlier lesson. So that's this slider right here. And I have all these blending modes, that those who are used to blending modes in Photoshop, they're available to you here, when you're trying to composite an image. But we're gonna just pretend we played with Luminance. Gonna zoom back. And I'm gonna go here, and these are little masks that I can draw on a filter. This is defined already as a circle, this is a square, this is of course, obviously a pen tool where I can draw any shape I want. I don't necessarily need to draw a very complex shape. My goal is to draw a big box, and basically say everything in the box, I want to see, and everything outside the box, just make transparent so I see my blue background. So I'm gonna go ahead, grab that box. It already draws one here for me. I'm just gonna, I could stretch it out, but let me see if I have a ... Ah, I do have a scale, but I'm gonna do it so you can see. Just gonna grab the corners. Okay. Gonna draw it out, as far as I need to. That's okay. Pull it out. So, if I turn off the keyer, basically this is what I've done with the mask. It's just a shape. So, I could have done this first. So now when I've combined this mask with the keyer, I now have her over a blue background, and I've removed the green, and I could put her over anything I choose. But, hopefully now you have the basic skills to work with the Ultra Keyer, and you can see, it really is an amazingly powerful tool. Originally it was a self-contained application. Then it was part of After Effects, and now, not only is it After Effects, but now it's also part of Premiere, so I don't even have to jump into a new scary application. You can stay in this less scary application, that hopefully is way less scary than it was four weeks ago, when you started learning Adobe Premiere, and you were all afraid of it, to where now you can really ramp up the look of your show, and hopefully you feel you have enough control to master your edit, and take your videos to the next level. And with that, I wanna thank you very much for joining us for the last month.