Masks are very necessary when you key. Not only can they be used to key out the green color of the green screen, but you can also use masks to keep in some of that green. In this movie, author Luisa Winters describes what garbage masks are and how to use them to key a subject in Keylight in Adobe After Effects.
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- [Instructor] Mask, the embedded alpha is added to the Inside Mask, and then you have Normal, which is the default value. The embedded alpha is used to keep the layer as normal. So how would you use this? Well, let's imagine we need to increase the screen balance of the clip to a huge value, for whatever reason. So, let's go ahead and change this to the Screen Matte, and change the screen balance to a lot.
Say, something like this. If I go back to the Final Result, and I change maybe the Screen Gain a little bit more, you can see how the transparency of these pixels is not working great. Let's go ahead and see the Screen Matte. You can see that some semi-transparency was introduced here, etc, etc. Well, now change this view to an Intermediate Result.
And duplicate Keylight. To duplicate the effect, all you have to do is select it, and use ctrl + d on Windows, cmd + d on the Mac. And that duplicates the effect. Now we have two different Keylight effects, that were applied to this one clip. Now, let's go ahead and change, under Inside Mask, the value of the Source Alpha to Add To Inside Mask.
And you can see how immediately, we have a super clean key. We do this for when we are introducing transparency, where we don't want any, and now we need to work on the edges of the clip. Now I can use the second version of the Keylight to work on the edges of this matte.
- Shooting for the key
- Basic keying
- Refining the matte
- Masking a key
- Correcting color