Easy-to-follow video tutorials help you learn software, creative, and business skills.Become a member
It can be tough to see a layer mask on the tiny layer mask thumbnail in the Layers panel. Viewing a layer mask large in the document window is a better way to understand exactly what you have masked, and to fine-tune the mask. For example, here I have a layer mask on the paintbrush layer. You can see in the layer mask thumbnail on the layer in the Layers panel that there is some black, maybe some gray paint on the layer mask, but you really can't see where. So when I'm making a layer mask like this one, from time to time, I'll check it in the document window like this.
I'm going to hold down the Option key on my Mac, that's the Alt key on the PC, as I click right on the layer mask thumbnail, and that reveals the layer mask here in the document window. I am going to zoom in a little, so that you can see that there are some straight pixels down here at the bottom of the mask, and those are hiding parts of the paintbrush layer. And they really aren't the way that I would like the mask to be. One of the advantages of viewing the layer mask here in the document window is that I can fine-tune it right here. Because a layer mask is basically a gray scale pixel based document, I can use any of the tools or features on it that I would normally use on a pixel based image in Photoshop.
For example, I could filter this mask or adjust it, or I could paint on the mask right here in the document window, with black, white or gray. I would like to get rid of these little specks down here. So I'm going to paint over them with white here on the layer mask in the document window. I'll go to the Toolbox and I'll select my Brush tool. I'll make sure that the foreground color is set to white, and if isn't I'll press D on my keyboard, and then I'm going to go come into the image, and I'm going to go paint over those little specks.
And that's changing the shape of the layer mask. I might do a little bit of that over here too with there are some square looking pixels. And when I'm done, I'll go back to the regular document view, by going back to that same layer mask icon, and again, holding the Option key, on the Mac or the Alt key on a PC, and clicking on the layer mask icon. And you can see that I have modified my layer mask, so I don't see any little speckles down here, around the area that I have masked. I'm going to go back to 100% view by going to the Toolbox and double-clicking the Zoom tool.
That's a shortcut for 100%. There's another to way to view a layer mask in the document window, and that is to leave the image showing, but also view the mask as a kind of a red overlay. That resembles the kind of overlay you may be used to seeing in Quick Mask mode, when you are working with the selection. To see both the red overlay of the mask, and the document, here's what you do. Just make sure that you have the paintbrush layer selected, and then press the Backslash key on your keyboard. That's the key just to the right of the right bracket key.
So this part is showing the mask, and this part is showing the image on the paintbrush layer. I'm going to zoom in again to the paintbrush, because now that I have the red overlay, I can see that when I created the mask, I went too far, and I covered part of this green paintbrush, hiding it from view. I don't want that, so I'm going to fix that by going to the Layers panel, making sure that I have the layer mask thumbnail highlighted there on the paintbrush layer, and then getting the Brush tool in the Toolbox. Making sure that I have white paint as my foreground color, and moving over to that part of the mask and drawing over it with white, which as you know reveals the content of the layer to which the mask is attached.
In other words, I'm revealing this green paintbrush again. When I'm done working in this view, I can press the Backslash key again to go back to the regular view. And I'll double-click the Zoom tool again to go back to 100%. I'd like you to take a look at the Channels panel for just a moment. I'll go there by clicking the Channels tab just to the right of the Layers panel. Notice that in addition to the RBG and the Red, Green, and Blue color channels, there is another channel here. By default, it carries the same name as the layer that contains the layer mask, which is the paintbrush, and the word Mask.
What's happening here is that whenever you have a layer selected in the Layers panel that has a layer mask on it, you'll see an extra Alpha Channel here in the Channels panel that represents that mask. A layer mask is basically a channel mask that's attached to a single layer. This Alpha Channel will be here only while you have a layer that has a layer mask on it selected in the Layers panel. So if I click off this layer in the Layers panel, and then I go back to the Channels panel, you won't see that extra channel anymore.
But I'd like to bring that channel back for a moment, so that you can see how that Backslash toggle works under the hood. So again, I'll go to the Layers panel, I'll select the paintbrush layer, I'll go back to the Channels panel, and there is my Alpha Channel for the layer mask. Now, notice that when I press the Backslash key, so that I can see both the red overlay and the image, the eye icon has gone on on the paintbrush mask channel, and when I press that key again to go back to regular view, the eye icon on that channel goes off.
So what's making the red overlay appear is basically making the temporary paintbrush mask channel visible, and then invisible. But you never have to come into the Channels panel in order to make all this work. So I'm going to go back to the Layers panel, and I'll finish off this lesson by reminding you that when you are working on an image, it's really useful to be able to view the layer mask in the document window, either as a grayscale mask, or as a red overlay, so that you can evaluate your mask, and fine-tune it to get it just the way you want it.
Get unlimited access to all courses for just $25/month.Become a member
120 Video lessons · 64657 Viewers
119 Video lessons · 71917 Viewers
125 Video lessons · 32519 Viewers
84 Video lessons · 18989 Viewers
Access exercise files from a button right under the course name.
Search within course videos and transcripts, and jump right to the results.
Remove icons showing you already watched videos if you want to start over.
Make the video wide, narrow, full-screen, or pop the player out of the page into its own window.
Click on text in the transcript to jump to that spot in the video. As the video plays, the relevant spot in the transcript will be highlighted.