Subtitles of the Movie

Sometimes when you're compositing you want to have a character that's going to be able to move in front of a background, or you might want to do an animation, or a sequence, where you have a car riding along on a highway and you want to add elements like maybe a boulder heading toward it, but you don't want to see anything behind the boulder. In that regard, you need something known as an Alpha Channel. So what I'm going to do is show you how you can easily create one yourself in Photoshop, and I'll also talk about one of the file formats that you might want to use for making Alpha Channels. As you can see here I have my character of this bunny and he's really in anguish over getting down to the last drop of coffee, and I made this in Lightwave just for some fun, one of those rare treats. So, what I'm going to show you here is, in the Layers Panel I have the bunny in front of this black background and when I hide that background we see that the bunny has these checker marks behind him. Now, by now of course that the checker marks pretty much mean that there's really nothing there, and these are just indicators as to what regions are transparent in this image. Well, After Effects is able to understand this itself, but it depends on how you save this file. So what I would do is, if you have a character that has, let's say, artwork around it, I would take my time and use the Lasso Tool to get rid of that stuff and then copy your character and paste it on a new document that has a transparent background. For example, let's imagine that there was a city scene behind this bunny and I took my time and I cut him out so he's by himself. So I would go to copy this entire character and paste it on a new document and I would make sure that the background contents are transparent and then I would Paste them on there, for example. Then I would Save As the PNG format, which stands for Portable Network Graphics. You can also use a Targa and any other format that will allow you to retain that transparency information. After you do that you can then bring that into After Effects very easily. As you can see, I have the bunny. PNG and I also have another image. I can have a rooster, or I can even make a solid. As a matter of fact I'll make a new solid right now and I will make this blue and I'll drag this into the Comp, as you see I have here, and I have my bunny and all that stuff. Now if you look in our Layers, down here, the solid is currently in front of that bunny. So I'm going to click on my bunny and drag it to the front of that solid so now we could see that the bunny is moving in front of that block of color because After Effects, once again, remembers that there was a checkerboard there and we had that Transparency. So, that is pretty much an Alpha Channel in a nutshell. It's simply data that stores information that's going to show you the pixel areas as well as remember what parts are transparent.