Join Deke McClelland for an in-depth discussion in this video Introducing opacity masks, part of Illustrator CS6 One-on-One: Mastery.
In this movie I'll introduce you to the opacity mask feature and I'll also show you a couple of uses for it. So let's say that I want to take the submarine and cut a hole in it. Because in the back of the sub if I turn the sub layer off, you can see the word love, and I want to go ahead and reveal that. So I'll turn the sub layer back on. One way to work, would be to take this rounded rectangle here that I've created in advance. And combine it with this compound shape in the background, in order to create a hole. And you can do that by bringing up the Path Finder panel, and then because we're working with the compound shape, you have to press the Alt key, or the Opt key on the Mac, and click on the minus front icon, in order to produce this effect here.
The interesting thing to note, though, is this is not a pure hole. What we're doing is carving a hole in the path outline and then Illustrator is turning around and stroking the inside of that hole as well. What if we want to create a hole in everything. In all of the attributes, for example, both fill and stroke. Well in that case you need to use a opacity mask. So I'll go ahead and press Ctrl+Z or Cmd+Z on the Mac in order to undo that change. And then I want to go up to the Window menu and choose the Transparency command in order to bring up the transparency panel.
Mine's already up over here on the right hand side of the screen. Next, you need to expand the panel by clicking on this up-down arrow icon a couple of times. We don't need the check boxes but we do need a little more room on screen, so I'm going to click, yet again, in order to hide those. This central area right here is where you make and modify the opacity mask, starting by clicking on make mask. When you do that, you go ahead and turn the top object in the selection into the mask, and then it masks everything else that was selected as well.
Now by default, white represents a reveal, which is why we can only see the portion of the sub inside the rounded rectangle, and everything outside the rectangle is clipped away, as indicated by this clip check box. If you turn the clip box off then you reveal everything outside the shape as well. If you want to turn white into a concealing agent instead, that is white cuts holes, whereas normally black does. Then you turn on the invert checkbox, and you'd end up with this effect here. And then if for whatever reason you decide you want to clip away everything outside the rectangle you would turn the clip checkbox back on. So I just want you to see all these variations.
Now coming to terms with these checkboxes can be a little confusing at first, when you start using an opacity mask, which is why we'll revisit this topic in future movies. But for now, I'm going to turn clip off and leave invert mask turned on. I want you to notice something about the mask. Notice how it's cutting a hole inside the shape, and it's not getting stroked this time around. Now, if you want to modify the location of that rectangle, as I do just to make a point here, then you want to switch to the opacity mask, And you do that by clicking on this right hand thumbnail inside the transparency panel. And that will make the opacity mask active.
I also want you to notice what happens to the layers panel. As soon as I click on the right hand thumbnail, Illustrator goes ahead and hides all my layers and shows me just the opacity mask. And notice, it even tells me that's the case at the top of the layers panel. And you can add as many path outlines as you like to this opacity mask. However, you cannot divide the mask into layers, as indicated by the dimmed icons, down here at the bottom. Anyway, I'm going to go ahead and take this guy and move it upward so that you can see that it's not only cutting a hole in the path outline, but it's also cutting a hole in the fill and stroke attributes.
And that's the difference with opacity mask. Also it turns out they're way flexible as we'll see in future movies. Anyway, I'm going to press Ctrl+Z, or Cmd+Z on a Mac, to reinstate the position of that rectangle. If you want to return to your illustration, you just go ahead and click on the left-hand thumbnail up here in the Transparency panel, and then you'll regain access to all your layers once again. All right, so I think that's pretty illuminative, but it's not very practical. So, I've got another example in here. If you twirl open this fab four layer, you'll see that there's this path outline, it's really a rectangle.
Go ahead and turn it on if you're working along with me. And then, I'll go ahead and click on it to select it so that you can see that I've added a bunch of anchor points here It's here using the add anchor points command and I want to be a wavy mask as well, so that these guys look like they're coming out of the water. First thing you need to do is select all the objects that you want to mask and you do that by clicking in the top right corner of this layer and then I will select all the contents of the layer as you can see. And then the top path outline is going to become the opacity mask as soon as you click on Make mask.
Now remember how I was telling you that white reveals, black conceals, so we're going to clip away their feet. We're also clipping everything outside the shape, because the clip checkbox is turned on. So we need to turn that off in order to produce this effect here. Then click on the right hand thumbnail. So that we can edit the path outline. And go into the effect menu. Choose distort and transform. And choose zigzag. And turn on the preview check box to see what's going on. Obviously, that's not the wavy pattern I'm looking for. So I'll go ahead and switch the point setting to smooth. And then, I'll take the size option down to two points, and I'll change the number of ridges per segment to two as well, in order to produce this effect here. Then click okay, and now you can exit the opacity mask. By clicking on the left-hand thumbnail.
And now I'll press control shift A, or command shift A on a Mac, so you can see what's happened. Now let's say I don't really want that hole that's carved into the sub. I just want to show you one more thing you can do here. I'll click on the sub to make it active. And notice the button that was formerly called make mask is now called release. And all you have to do is click on it and then the mask goes away. And for my part, I figured I'll just go ahead and turn that white rectangle off, because at this point we no longer need it. And for the sake of the illustration, I'll go ahead and twirl open the sea and sky layer. Scroll down to this group object right here, go ahead and meatball it to select it, and then drag this little blue square up to the sublayer. So that the word love appears in front of the sub, where it really belongs. And that friends, is my introduction to opacity masks inside Illustrator. We'll see lots more uses for them in future movies.
- Setting up angular construction guides
- Kerning and clipping hand-drawn type
- Creating and naming symbols
- Using symbols to simulate master pages
- Creating a gradient mesh
- Using gradients to cast shadows
- Fading artwork with a gradient opacity mask
- Warping and distorting artwork with Liquify and Envelope
- Assembling a seamless pattern brush
- Creating charts and pictographs
- Working in 3D space