Does the edge of your matte have either a harsh line, gray pixels, or both? How do you smooth out the edge of your matte so the subject blends better with the background by using Keylight in Adobe After Effects? In this movie, author Luisa Winters walks you through how to use Clip Black and White to refine your key.
- So far, we have been adjusting these settings in the order in which the effects has them, and I see no reason to change that. The next segment is the screen mat in which we will be strengthening the mat to pull an even cleaner key. Let's do it. Go ahead and open Composition 3.1 Clip Black and White. In here, we see a slightly different shot. It already has key light applied to it. You can also see that we have a mask already applied to this.
To see the mask, all you have to do is click on the clip and now you see it's a rectangular mask. Let's go ahead and switch the view to a screen mat view. For that, click on this drop down menu here and then switch to screen mat. Let's go ahead and zoom into this a little bit and let's move the screen so that we can see this a little bit better. Let's zoom in a little more, sort of around 200% here, let's just look at the shoulder here and you can see that there are a lot of grey pixels that maybe we don't want to have, and the edges here don't look to soft, they look rather harsh.
For that, we're going to adjust the clip black and the clip white. To adjust the clip black, let's go ahead and zoom out so we can see more of the black here, and adjust the number. You can adjust the number a lot or just a litte. Obviously, if you adjust it a lot a lot a lot, eventually, the mat disappears. We really don't want that, so we're just going to change this a little bit, let's say around 20 something, and what I'm looking at as I change this is this in between his two feet.
So this is going to look like his shadow, but we don't want it to be so prominent. So as I change this, and let me zoom in so you can see it a little bit better, as I change this value here, you see how these grey pixels here become a little bit darker, or lighter depending on where I go. That's a little bit much, so a value of 61 is a little bit much because now I'm losing some of the detail here in the shoe, but I can still have a little bit here, somewhere around 29 or so, and this shadow will still show up, but I will keep the detail on the shoe.
So now I need to strengthen the white part of the mat. So let's zoom out so we can see this a little bit better. Let's go ahead and adjust the clip white value, and you see that if I change it a lot, the edges start becoming very very crunchy. Let's zoom in so you can see that a little bit better. Now I'll change the clip white value. I am pressing and holding the ctrl key on windows, the cmd key on mac, so that these numbers change a little bit slower than what they were changing before.
I'll leave it somewhere around here, and if we zoom out, we're going to see that they're only some pixels here that are semitransparent and we're going to fix those a little bit later, and now I'll change to a final result so that you can see the actual transparency. Again, when you are adjusting these values, be careful that you do not adjust too much, or you could be destroying the edges of your subject. So, for these values, just a little bit is really all you need.
If I were to zoom into this, maybe I'm destroying these edges a little too much, but for now we're going to leave the values like that.
- Shooting for the key
- Basic keying
- Refining the matte
- Masking a key
- Correcting color