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- Introducing Premiere Pro: the compositing program
- Understanding transparency and alpha channels
- Adjusting opacity
- Working with garbage mattes
- Luma keys and chroma keys
- The Ultra Keyer
- Nesting sequences
- Understanding and using blend modes
- Creating track mattes
Skill Level Intermediate
I've got a composition setup here which could be potentially quite challenging for keying. If I just bring up the foreground video nice and large for you, you can see that although this was shot in front of a green screen. In fact this is shot in front of the same green screen as all of my other green screen media. The camera was completely miscalibrated. And I've seen keying contents like this before where it seems like at the time everything was set up fine but nobody was checking. And you can see this bright vivid green in the background is completely gone.
In fact the exposure is very low. And the colors are totally off. If we look at this, for example, in the Reference monitor we can see that the contrast range is very, very low for this shot. And if we look at the vetroscope you can see we're way over towards the red. We're not getting a very good source image. I've layered this video clip over a clouds layer. This is clouds that were generated inside of After Effects.
And all I've done is taken this black and white procedurally generated cloud background. And I've thrown onto it the tint effect in Premiere Pro which has allowed me to give it kind of blue cream sky like effect. It's obviously fake but it looks a little bit nicer than the black and white. So what I'm going to do is I'm going to start by throwing on the Ultra key. And I'm going to see what kind of results I can get with my foreground.
So let's just throw it on and I'll pick out a color. I'm using the eye-dropper here. And actually it does a pretty good job. If I look at my alpha channel you can see yup, I need some cleanup. So I'll perhaps work a little bit on the pedestal, maybe bring down the highlights a little bit. It's not great, but I might be able to work on the contrast a little, and before you know it, I've got a pretty good key. Now there's some things I'm not going to be able to help with.
For example, if you look at the color board that I'm holding in this shot, there are some dark colored sections. Which, if I just come back out of full screen again, is because they're bright blue. And so, it's going to be pretty obvious that the key is probably going to pick those up. The other problem I've got is that I seem to be pretty magenta. Now, if I want to, I can go down to my color correction. And perhaps I can play a little bit with the hue and try to bring myself back around.
The problem with hue adjustments is that they rotate the entire color wheel around. I can bring down the saturation a little bit and I can maybe bring down the luminence or bring it up a little bit. But there's a limit at how much I'm going to be able to acheive with this because I've just been recorded at completely the wrong color temperature and in completely the wrong way. So this is an example of where I think you'd be better off using some color correction before you apply your key. I'll just get rid of this Ultra key by selecting it and hitting the delete key on my keyboard.
Backspace key'll work too, and I'm going to bring up just a simple fast color correcter, I'm not going to bother with the more advanced 3 way or RGB color correcter. And I'm going to throw the color correction effect onto the clip before I get to the keyer. Now, if I go to my Reference monitor. I can see right away that I've got his very very strong color cost. And what I'm going to do is start off by benefiting from the fact that I'm holding this color chart.
I suppose what I'm doing here is I'm singing the praises of having these color charts on set. Because, when it gets to post production, there's nothing quite like doing this. I'm going to, just set these to 100% so you can see what's going on. I'm going to select the white balance eyedropper inside of the first color corrector and I'm going to click on the white square of that Color charts and bingo. Instantly you can see that I've got much more natural colors. And the green is now green. And if you look at the Vectorscope.
We've come way back over to the center. We've got a massive improvement in color. And we can see just by looking at the Effect control panel. How far off white was because of the calibration of the camera. If I now switch over to looking at my waveform display in the Reference monitor, I can see that I don't have a great range here. We're use the millivolt scale here because this is Powell Media. And power media goes from point 3 volts to 1 full volt. And you can see that the shadows are okay, but I really have a terrible contrast range. So I'm just going to go into my input levels, and I'm going to pull this back up to give myself some highlights.
Now, I don't want to go crazy with this because we are mostly looking at mid tones. We've got the green there, my skin; there's a lot of mid tones in the shot. But I can bring this up a little bit to try to make it look a bit more natural. And one of the problems that you'll see, particularly with the heavily compressed video formats, is that the smaller cameras with the smaller chips very often hide grain in the shadows. And if I go full screen with this, you can probably see around the background of the green there there's quite a lot of video grain. And this I what happens in the lower lighting situations. You might be able to get some results by using a median filter or something like that to smooth it out, but we'll stick with this for now. Now that I've got this much better look, in fact I might just... Y'know, I might just go crazy and pull that over a little bit more to bring the whites out in my shirt.
I think that looks a little bit more natural. If I now go back to my Ultra-keyer, write this on to my clip, get my key color, click somewhere in, I can see there's a bit of darkening here near my head. There's light pools here and over to the right, but if I go for the, somewhere near my neck there, we get a pretty good key. And if I go to my Alpha channel, not too shabby, not too bad at all. I'm just going to maybe bring up the Pedestal a bit...
Maybe bring the highlights in a little. Let's have the tolerance up, set the mid point, increase the contrast, and I'm getting a pretty good key. There we go. Now, there's not a lot that I can do about the board in the center, but if I just take a look through this. Yeah, it does look like I'm not moving around too much, so this might be a good opportunity for me to get a garbage map. Just a four point I reckon should do it.
Throw this on and, if I now, rather than setting this as including parts of my media, I'm going to want to set it to exclude. I want to just have this board. And the only way that you can do that in Premiere Pro is, if I just get rid of this, is to select your clip. Ctrl+C or Cmd+C to copy it. Cmd+V or Ctrl+V to paste and make a copy. Let's put this over on top, there we are. In this instance I will get rid of the Ultra key because I don't need it and I'll put my 4 point garbage mat on.
Here we are. And just set that for my board. And this way, I'm using one instance of my media to get my background visible. I just set this screen so you can see what's going on. And I'm using a second instance, perfectly lined up to give me this foreground element. And because this is in front its going to be ignoring any kind that I've created using the ultra effect in fact its not using the ultra effect at all. Right now click away and play through lets see what we get. > > So this is meant to be white, right.
Now, to my eye, there's still a little bit of a tint on that and I might want to do a little bit more color correction work. But by Duplicating the Layer after I Apply the Fast Color Corrector, I'm just getting a pixel to pixel copy and it works just fine.
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