Join Steve Grisetti for an in-depth discussion in this video Using Chroma Key and Videomerge, part of Learning Premiere Elements 13.
You know doubt encounter chroma key effects on a regular basis, whether you are aware of it or not. Keying removes the background from behind an actor, for instance. Replaces it with any real or imagined background. So you see this process used in everything from big budget fantasy and science fiction movies, to the nightly tv weather report. Now you can do it on your home computer. So the basic principle of chroma key, is that you take a clip, for instance in our Project Assets panel, we're going to double-click to open this up in the clip monitor. We have a character standing or an actor standing in front of a green screen.
This screen might also be blue. Generally green and blue are chosen, because they're not in human skin tone. And whether it's green or blue usually depends on the color of costumes the actor is wearing. In this case, we've got an actor wearing blue, so we're using a green screen. And what we're going to do is apply an effect that is going to remove this background from behind the actor, make it transparent. So everything that's green in here is going to become transparency, and then, if we've got a clip on a track behind it. We're going to see through this clip and see that new background as the background here in the clip.
We have this clip here which is a photograph of an orchard or a farm. And you notice by the way that this clip doesn't fill my video frame. That's pretty common because I'm using a 16x9 video frame, and I have a 4x3 photograph, which is what photographs tend to be. Now I could manually size it up, which I don't like to do.I don't like to size up, so I'm going to Ctrl+z, Cmd+z, to erase that. What I recommend, on the other hand, is that this came in with the preferences.
Set to scale, default scale to frame size. And when that's set up whatever you bring into the program will automatically be sized to fit within your video frame. We don't want to do that. I like to use my photos at their actual size. I have sized this photo so it is only slightly larger than a video frame. So if I right-click and turn off the option Scale to Frame Size. Now my photo fills the frame, and in fact it's a little larger than the frame. And I can size it down. I highly recommend you size down rather than size up.
And now this is going to be our new background for our actor. Let's go to project assets and we'll drag the chroma key video down here to the Video 2 track directly above it. Now, when you do this with a clip that has a smooth background, you're going to get this pop-up. Do you want to apply a video merge? Well we do, in this particular case but not at this time. And in fact, I don't like this little pop-up. It comes up automatically and it will often come up whenever you've got a picture that has a smooth background. Somebody standing in front of a wall.
Cloudless sky, like a nice even blue sky, it thinks you're trying to create a chroma key effect. So I say, hey, don't show me this. And click no and I won't ever see it again. So we've got our green screen image sitting on top of our background. I'm going to extend the background and because this is a still photo. I can just stretch it out so it's the same length as our foreground image or our key image. If this were live video behind him, of course, you would have to have a clip that was at least as long as your green screen video. That said, let's go to our video effects here on the action bar.
And just kind of stretching it up to make the panel bigger. We'll go to our keying effects. Now there are three main effects you're going to use to create this keying effect look. One is the blue screen effect. One is the green screen. And the other is the chroma key. Now chroma key is kind of the default, but green screen and blue screen are already preset for the color of background that tends to be used in a green screen or blue screen. By the way if you want to get your hands on some nice inexpensive green screen check out tubetape.com.
It's a great place to buy already nicely colored backgrounds. They will sell curtains inexpensive. Paint whatever you want so that you can create your own nice green screen and blue screens that are keyed in to the type, or the shade of green or blue that are most commonly used to create the keying effect. We're going to start with the chroma key effect. I'll drag it on to my chroma key video. Now if you have a Macintosh, and if you're running this on a Mac, you won't see green screen, blue screen, or chroma key. Those effects are not included with a Mac version program.
However there is an alternate effect that you can use that may actually work better. When I grabbed chroma key and added to the video, you notice that it already is keyed to black for some reason. And it was removing part of this man's helmet. Part a little shadow under his arm. That's not really the color I want to remove, so I can set the key color. I can do that by clicking on this little eyedropper. I get an eyedropper, which I use to select a nice medium version of the green background.
This is a nice smooth color of green. I don't want any wrinkles. I don't want any hot spots. I don't want any shadows on it. And when I select the background you can see that it starts to key it out. Now when you make adjustments to the key effect, I would recommend you stay with similarity and blend for the most part. These lower effects here are good for fine tuning. But similarity and blend are going to be the ones you use, especially similarity here to set the key. And I don't want to remove too much. I don't want to remove part of the actor, but I want to get rid of as much of the green as possible, and blend will kind of soften that.
That's actually pretty good, but if I want to see how good it really is, go down here to the bottom of the effect settings and click on mask only. Now we can see what areas are not being keyed out. And you can see we've taken a little bit more than we should have. So I'm going to adjust similarity there. There we go. Just blend just a little bit. And that's probably closer to where we want to start. So we don't want to lose any of the actor but we do want to make all the green area transparent. When I turn off the mask only.
I can see my result, and now I can do a little fine tuning. We'll just remove similarity just a tweak. Blend it. And maybe I can play with threshold and cut off. But we've got a pretty good effect here. And when I play it through, you can see our actor seems to be standing in front of the background. Now we do have a little bit of green fringing around the outside here. So I want to experiment here, and I want to select chroma key and just click the trash can to delete it. I want to try the green screen key. Drag it on here. Now this is set, or preset, for the green.
And you can see it does a great job of just popping the green right out of there. That's pretty cool. It may make some fine tuning adjustments so that we're getting, we're not subtracting too much of the image. But, as you can see, the Green Screen Key does a great job of being preset for that image. Now, if you have a Macintosh, you don't have access to those keying effects, but you do have Video Merge. Now Video Merge can be launched a couple of ways, both on the Mac and on the PC. You saw that it can be launched automatically when you add a clip that has a smooth background.
We've turned that feature off now. You can also just right-click and select Apply Video Merge. Or you can go to the Effects Panel. And go to the Video Merge category. There it is. And we'll drag it onto our clip. Now this is a greatly simplified version of chroma key, but watch how effective it is. So we've got our character and just what you see on the default application it does a pretty job removing the background. We got a little bit of fringing up here in the clouds. I'm going to select the option to select the color.
And then I'll click on my eyedropper. And use that to sample a background. And look at video merge how nicely it has removed the background. Now when working in chroma key we had a lot of adjustments to make. In video merge you pretty much have tolerance and that's pretty much all you need to adjust. And it does an excellent job. I think in a lot of ways this does a better job even than chroma key or green screen key in creating this green screen effect. Isn't that terrific? And if I render it by clicking on the render button or by pressing the enter or return key on my keyboard, we'll see it even more smoothly, and look how clean that is.
Isn't that a great job? Chroma key and video merge fall into a category I like to call the magic effects. They make something that isn't real appear to be real, and ideally, they do it without the audience even being aware of the effect. For my money keying effects are some of the most fun effects in the program to play with, I really love them.
- Adding media
- Managing files with the Organizer
- Using Quick view vs. Expert view
- Adding, splitting, and trimming clips on the timeline
- Creating a motion path with the Pan & Zoom tool
- Speeding up or slowing down video segments with Time Remapping
- Adjusting color, lighting, and audio
- Using Chroma Key and Videomerge
- Building custom music tracks with Scores
- Creating fade-ins and fade-outs
- Adding text animation
- Keyframing video effects
- Burning a DVD, AVCHD, or Blu-ray disc
- Uploading your video to Facebook, Vimeo, and YouTube