Subtitles of the Movie

Welcome to this lesson on the Alpha Channel. Alpha Channels can be mysterious and confusing but in practice, once you get to know them, they are not. And in fact, they're very useful. Think of Alpha Channels as additional hidden storage space in a file where you can save information from masks and layers and recall it at a later date. You can also save selections to disk and use them in other files, but if you want to keep them with the file you would save it to an Alpha Channel. You can also do the same thing with masks. So I've got a file open here that I've got some vector objects that I'm masking out the windows of this car. So if I select one, I can choose Selections from Vector Object and I just made a selection of that driver's side window. Now, I can save that to the disk or I can save it to the Alpha Channel. I'm going to select Alpha Channel. This allows me to add it to actually another open document if I want to and I would choose that here, name it. Let's call it Driver Window. You can actually move it if you like or leave it where it is in proportion to the entire document window and then Save. Now, that selection, I can deselect it, I can delete it to this vector layer, I can do anything I want to and to get that selection back all I need to do is select Selections, Load, From Alpha Channel and you can see that selection is saved within this document and I can, if there were more, I can click this arrow and load up by name the one I want. And then I can either replace, I can move it around, invert the selection. Let's just load it. There it goes. Now, I can right click and drag that if I wanted to to another part of the image but it doesn't have to be a complex shape. Let's say I want to, oh, I'll just draw a rectangle. Here I can make that selection, choose Selections, Load, Save, to Alpha Channel and call this selection Rect. Save. Now deselect this, come back to Selections, Load, from Alpha Channel and you'll notice that you've got two to choose from. Really cool. Now, if I take this file to another computer, put it on a laptop, put it on a FTP site where I can download it from another location, I will have these selections saved into the Alpha Channel and they're part of the data with this file. Very, very cool. You can also use masks as the basis of the data that gets saved to Alpha Channels and here I've got a photo of a building downtown that I've got three masks here, which affect how I'm changing the tone and the sky and the building. Each one of these masks serves a different purpose. So this mask on the right side I can simply select that, choose Layers, Load or Save Mask, Save Mask to Alpha Channel. I can change the name, I can get a preview, select Save and now that mask, the same was as Selection would be saved, that mask is saved to an Alpha Channel. Now, I can continue saving those one after another. OK. Now, let's say I turn all of these masks off, turn that whole group off, drag this. Well, I'll duplicate that. Drag that duplicate out. Hide everything in there. Now, if I want to apply those masks, all I got to do is come up here; Layer, Load, Save Mask, Load Mask from Alpha Channel, choose the one I want, decide on my orientation or options. Select Load and I just created a mask from the Alpha Channel. Very powerful and I would encourage you to explore Alpha Channels and use them as much as possible. It's space in the image that you can save and load selections and masks from.