Join Larry Jordan for an in-depth discussion in this video Creating a simple key, part of Final Cut Studio 2: Chroma Keying.
It's time to start keying in Final Cut Pro and as a note, the process of chroma keying inside Final Cut hasn't really changed since about Final Cut HD. So this technique will work with all the recent versions of the software. Here I'll show you how to create a simple key and then I'll show you some things to tweak. So let's open Final Cut and create ourselves a simple key. I am working with the project called 01 FCP Chroma-key and I am working in a sequence called 01a Seq_simple start. You will see the finished results over here in the finished versions of the sequence and then we are going to tweak and the tweaking will be in sequence number 2.
All right. Here is Megan sitting on the set that we just walked through and I have added her clip 2 to the timeline inside Final Cut. Now whenever we create a chroma key we actually have two layers to our key, we have got the foreground layer and the background layer. The background layer I have conveniently named to Background and it's just purple thing right up here. First thing that we have to do is, we have got to put our foreground and background layers in the right spot and a nice way to do that is to pull the Option key down and click on just the video clip. The Option key allows us to select just video or just audio. While holding the Option key down press the Up Arrow key. Option+Up and Down arrow allows us to move clips between tracks. So I just took Megan's clip and I have moved it up to V2. I will grab the background clip and just drag it underneath here. Shift+Z, so I can get the whole sequence to fit in a window and here is one of my favorite keyboard shortcuts.
If you ever want multiple clips to all end at the same spot. Select the clip whose ending you want to move and type the letter E. It does what's called an Extend Edit and it automatically jumps whatever edit points you have selected to the position of the playhead, provided you have sufficient handles. Whenever you are creating effects inside Final Cut you always want to make sure that your playhead is inside of the clip and in this case so that your results can match mine, I will park it right on this marker here called Start. In Final Cut, whenever there is a clip on a higher track, by default that clip on a higher track is 100% opaque and 100% full screen. In other words it totally blocks all the clips below it.
So, the only way that I can get to see the clip that's on V1 is to change V2 and the way we are going to change V2 is we are going to apply three filters inside Final Cut. They will make the green transparent and make it look like Megan is sitting in front of that blue background. To apply those filters, make sure your V2 clip is selected and go up to the Effects menu, go down to Video Filters, go to the section called Key and the order in which you apply your filters is critical. The first filter we are going to apply will be either Colors Smoothing-4:1:1 or Color Smoothing-4:2:2.
If you are working with DV material or HDV material you would want to apply Color Smoothing-4:1:1. If you are working with Panasonic P2 material or Digi-Beta material you would apply Color Smoothing-4:2:2. In this case we will apply the Color Smoothing-4:2:2 filter because we are working with footage, which was shot with a Panasonic P2 camera, and we will shot it in 720p mode. Now that we have applied that filter we go back to Effects, go down to Video Filters, go to Key and we apply our second filter, which is called the Chroma Keyer. When you apply it, everything will look worse don't panic. In this case it actually looks pretty good but we will still give ourselves sometime to tweak. Go to Effects, Video Filters and the last filter we apply is also in the Key category and if you are putting your talent in front of a blue screen you set it to Spill Suppressor - Blue. If you putting them in front of the green screen you set it to Spill Suppressor-Green. In this case we will do Spill Suppressor-Green and click that.
Now we have applied our three filters double click the V2 clip to load it up into the Viewer and click the Filters tab. Color Smoothing, we will open this up just a bit here, Color Smoothing is first, the Chroma Keyer second and Spill Suppression is third. In our particular case, I am going to turn off Spill Suppression and I am going to turn off Color Smoothing both of those will be turned on a little bit later. You can start to see that although the default Keyer inside Final Cut isn't bad at all just as its setting with that green, we can still see a little bit of green coming around the edges of the hair and we will tweak this just a bit.
So to adjust the chroma key we go up to the Chroma Keyer Filter. The Chroma Keyer Filter gets adjusted from top to bottom. This first line allow us to adjust the Color Selection, the second is Saturation, the third is Luminance and then this buttons down here, like a spice in a soup, you use just a little bit to get the results that you want. So, first these three buttons are what we are going to start. The middle button determines what we are looking at. When it's a red key on a gray background it shows us the finished result. When you click it and it's a black key on a white background it shows us the matte that is to say what's transparent and what's opaque. And when it's a red key on a blue background it shows us our foreground clip. Now you will notice that when I look at the finished result it's kind of hard to see her edges because they blend in with the background pretty well. So what we are going to do is we will click on this clip down here on V1 and go to the Modify menu and turn off Clip Enable. Clip Enable keyboard shortcut is Ctrl+B. It can also be toggled down here by Control+Clicking on the clip and unchecking Clip Enable.
When Clip Enable is checked, a clip is visible. When Clip Enable is not checked our clip is invisible, because I don't want to get confused by looking at this background clip, I want to make it invisible at least initially. Now let's go back to this V2 clip in our Key up here. When I set this key to be a black key on a white background it shows our matte. That which is white is opaque, that which is black is transparent. Our goal in creating this key is to have Megan our foreground person be solid white, no shades of gray and our background where we want to remove the green to be solid black. So we want this to be two choices either opaque or transparent. We don't want shades. So to set this I am going to click on a foreground which is a red key on blue and click my Eye Dropper and click right here on green and when I do, that Eye Dropper samples the green and loads those settings directly into the Keyer.
Now that they loaded we will switch this to a black key on a white background and you can see we are getting some grunge coming in here. Our goal is to get the background and the edges of her hair either solid black to be transparent or solid white to be opaque. We adjust each of these settings. This adjusts the Color, this adjusts the Saturation and this adjusts the Luminance has two set of dots. The top set of dots are the selection dots. The bottom set of dots are the feathering dots. I want to adjust these to keep them as close together as possible and I make a small adjustment and I look to see is there any change here and right now what I am seeing the change is in the hair, the top of her head.
When I stop seeing changes I then grab the next dot and move it and notice that I am now seeing a reduction in the gray dust that's in the background. When I stop seeing changes, I stop moving those dots, move the next set of dots, I don't see any change, move the next set up much better, much better. Once I have gotten the adjustment made, so it looks as good and clean as we can get, solid white in the foreground, solid black in the background. I turn off my mask and I view the finished result. Now we are going to see a little bit of green around the edges, that's okay, we will take care of that in just a minute. The goal of this is to have a clean key. If I Ctrl+Click on the V1 clip and turn on Clip Enable and I put her against the background we are seeing that we are starting to get a really nice looking key. Turn this back off again Ctrl+B would get the same thing.
Edge Thinning will make the edges a little bit sharper or a little bit -- notice how we are seeing more the hair up here when we really pull Edge Thinning down or we are losing the hair, when we take Edge Thinning up. My feeling is this varies on a key by key basis. Sometimes you will like the look and what I will do is, I will radically go in one direction, radically go in the other direction, and see which direction I like better. I like suppressing some of that stray hair up there and having it look a little bit cleaner.
What Softening does is it softens the edge of this key. The problem is if you use too much softening, we are not softening anymore. We are in X-Files territory. Well I don't want to quite soften it that much. So my recommendation is that when you are working with Softening, you use exactly one mouse click with this arrow right here, and it just cleans up all that stray hair, cleans up the edge of it. But it doesn't run the risk of causing our whole object to go completely out of focus.
Back in the old days, with Final Cut 3. 0 and earlier, we didn't have some of the filters that we have starting with Final Cut 4.0 and we needed to use the Enhance option. The Enhance option has been completely replaced by a couple of other filters and my recommendation is that you don't use it. So we would again toggle this middle button. Again we see the source, we see the finish and we see the mask and we will click it until we get a red key on a gray background. We turn on Clip Enable on V1 so we can see her against the key and we are getting pretty darn close. We still have a little bit of green around her hair, because this would shorten HD, let's blow this up.
Let's go to View, Video Playback and set it to Digital Cinema Desktop Preview - Main. When we do that if we press Command+F12, Command+F12 blows this up so we can get a much better idea, there is some green around her hair, green around there, a little bit of green around her shoulders. I just hit the Escape key to get back out and we get rid off that by going to the Filters tab, turning on Spill Suppression and just drawing Spill Suppression up and watching the screen, Command+F12 to go back in and notice how we are starting to lose that green background on it but we are getting a little bit of stair stepping around her hair. So we are going to have to just sort of find a happy ground.
What we have been able to do is to create a very simple Key, very clean key with Megan keyed against the background. So we have applied three filters, Color Smoothing, Chroma Keyer and dialed out the spill using the Spill Suppression filter. Your number is going to be between 30% and 60%. So that's the simple way of doing it. In the minute, I will comeback, I want to sure you some more things we can do, such as making sure that the colors are correct by using Scopes, adjusting colors with the Color Corrector and changing her position in the Motion tab. So there is a lot more to talk about. But for right now I think we will just take a quick break. Give yourselves a chance to reflect on this and I will be right back.
- Understanding how the production process affects the quality of the final key
- Fixing focus, lighting, and color issues
- Removing unwanted items in a frame using garbage mattes
- Removing green edges and stair-stepping
- Retaining or removing background shadows
- Handling motion blur and interlacing