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Advanced Masks in Adobe Photoshop

Lesson 4 of 4

Changing the Background

Ben Willmore

Advanced Masks in Adobe Photoshop

Ben Willmore

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Lesson Info

4. Changing the Background

Lesson Info

Changing the Background

But let's move onto other things, 'cause so far we've been using Select and Mask way too much. Fine, let's do something else. Ah, let's see. I'm gonna take this, and I want to put it on a new background. Let's make our new background first. I'll go to the bottom of my Layers panel, click on the Adjustment Layer icon and that's where I find a choice called Gradient. And with Gradient, I can choose from this little pop-up, I'll choose this gradient. And that's going to be my new background, I just needed something. I wanna put that underneath, so remember, the way I created it is I went down here to the Layer menu and to this little half black and half white circle. It was called Gradient. In order to put it underneath, I need to unlock this bottom layer, 'cause when that lock symbol's turned on, I can't put anything under it. Then I'll drag it under. All right, now let's work with this. All right, let's figure out how could we get rid of all that stuff? Well, I'm gonna go to the eraser ...

tool and that's what I'm gonna use. Now, you might think the eraser tool would take you forever to get rid of the background on this, but it doesn't have to. If you click and hold on the eraser, there are actually three tools in the same slot, one of which is called the Background Eraser. And that's what I want to do on this image, is erase its background. And I can tell (chuckles) I used this earlier 'cause the brush is so huge, usually a huge brush is helpful. And so, what I'm gonna do is the background eraser, first off, let me double check that it's on default settings. Take me just a moment. If you right click on the icon that is right here, for any tool, you can choose Reset Tool, and that's gonna get all the settings up here to their default settings. I just wanna make sure it acts like yours would if you were to use the same tool. I'm gonna use a big brush, and what the background eraser does is it looks at a crosshair that's in the middle of your brush, and when you click, it looks at what color that crosshair is, what it's on top of. And it deletes only that color from within your brush, so if I use a huge brush like this, and I click when the crosshair's on the blue sky, it should delete a heck of a lot of blue sky. Now remember, I have a layer underneath it that has a gradient, so when the sky goes away, you're-- I'm revealing what's underneath. So it deleted a whole bunch, I'm gonna choose undo because you'll notice, it didn't delete the sky in between those thingamajigs, whatever they are. This is what's called Watts Tower, by the way. If I remember right, it was in Los Angeles or somewhere. I could be wrong. And-- so there's a setting up here at the top of my screen, it's called Limits, and it's currently set to Contiguous. Contiguous means 'one unbroken chunk', and that's why it deleted the sky and could not go in between those metal, um, bars and things, because it needed to delete one unbroken chunk. Discontiguous means 'multiple chunks', so therefore they don't have to all connect together. When I set it to Discontiguous and I click in the same area, notice it's now deleting in between all of those little openings. Choose undo. Now, also up here is a setting that's called Tolerance, and tolerance means 'how much can it vary from the color that's underneath the crosshair.' Is it okay to delete things slightly brighter or darker? The higher the tolerance, the more it can deviate from the color underneath the crosshair. I betcha the default setting will be just fine. So what I'm gonna do is I'm gonna move to right about here, and I'm just gonna click my mouse. Then I'm gonna move to another area that still has blue, I don't know if you can see where I am, but I'm right down here if you're looking for that hand. And I'll click, and then I see some blue up here, so I'll move up to there, click. I see some remnants covering up the background over here, so I'll click a couple times. You can also click and drag with this. There we go. And I see some blue at the very bottom, click. There we go. And that works when we have a solid colored sky, like a blue sky, the background eraser can be great. But we can't use the feature called Select and Mask right now, because it needs a selection and we don't have one on our screen, or it needs a mask and there isn't one attached to this layer. So I wanna do something to convert this into a layer mask, where I can use that choice called Select and Mask, in case it would improve our results. So we're gonna have to get kind of tricky here. First, if I knew ahead of time that what I really wanted was the original picture with a layer mask attached, what I would've done is before I did anything, I would've duplicated the layer, so that I'd have the original still in here. And I didn't think to do that, 'cause we hadn't talked about it. So here's how to cheat and act as if you duplicated the original layer before beginning. I'm gonna create a brand new empty layer, and then I'm gonna go to the Edit menu and choose Fill, and I'm gonna choose a choice called History. History means 'fill with what my picture looked like when I first opened it.' So now I got my original picture in there. Now what I'd like to do is add a layer mask to it, and I want that layer mask to reflect what's hidden, on the layer that's underneath it. I hide all, everything except for it, that represents this. Here's how I'm gonna do that. There's a trick! If you go into your Layers panel, and you move your mouse onto the thumbnail image for a layer that has a checkerboard around it, like this one does, the checkerboard indicates what's empty. Well, you hold down the Command key, Control in Windows, and click on that little picture. And if you do, it's gonna select everything that doesn't look like a checkerboard. And therefore, it just selected everything that was in that layer that wasn't empty. That's Command + clicking on the thumbnail picture for a layer, Control + clicking if I'm in Windows. Now I'll go to the layer that's on top and I'll turn it back on. We have a selection, let's just add a layer mask, and the selection will be converted into the mask. Once I've done that, I can just throw away that middle layer, I don't need it anymore. So now we have our original picture with a mask limiting where it shows up. And now that we have a mask, if I click on the mask, we can always come up here to Select and Mask. It needs a selection or a mask to work on, and now it has one. I don't know if we actually need it right now, but just so you know, we could use it. Now let me show you some tricks about working with masks. I'm gonna view this mask, I'll do that by holding down the Option key, that's Alt in Windows, and I'm gonna click within the little thumbnail image that represents the mask in my Layers panel. When you Option + click on that mask, you can view it. Well, let's zoom up on it, see if there's any issues with it. And (chuckles) my screen's a little dirty, so it's hard for me to tell, but I think I can see an edge right here that looks kinda like a circle, like a huge circle, where it's black up here and it's not quite black there. Well, let's look at a trick. If I grab my paintbrush tool, and I paint with black, with default settings, what's gonna happen is when I paint, I just literally paint, and that's not what I'm looking for. So here's a trick: if you change the blending mode of your paintbrush tool to a choice called Hard Mix, then when you paint, it's going to protect areas that are white. So when I paint, anything that's pure white will not be changed. But things that are close to pure white do change, and I don't want them to. So I'm gonna lower the opacity on my brush, at the top of my screen, down to about 20%. That's low enough so it's gonna make almost no change whatsoever to things that are close to white. So now when I paint, I can just see that I cleaned up that little part of the background, I don't know if you could see it or not there, but it did, and it's hard for me to tell as far as dirt on my screen versus clean background, but... Then that same thing works if I switch and I paint with white. Now it's gonna protect black. It's not gonna allow me to change areas that are black, or close to black, and it's only gonna allow me to change things that are brighter. So I'm painting with white, and watch, I'm gonna paint right here, watch the background. Didn't change. But look at the image, it is changing, where it's white. So I might paint in there a few times to clean up those areas that were partially transparent. I can paint all the way up the tower if I need to, to kind of get those areas that are partially transparent, which are areas that have gray in them, to clean up. And right in here, in between, I can see where I don't have solid black. So that's where I switch to painting with black, and I paint and it'll clean that up, might have to paint twice. So that's a trick that, you know, only if you're good at Photoshop, where you know blending modes and other things you can do. Now when I'm done, I change this from Hard Mix back to normal and I put my opacity back to 100, otherwise next time I paint, it's gonna really mess me up. I'll Option + click on the mask in my Layers panel one more time to hide the mask, so you can see our end result. Let's do one more. Here, I'll open two images and let's remove the background on what? Some smoke. I'll use my Move tool, I'll click within this image, I'll drag it up to the other one, drag into, I just need to have my mouse inside that image, and I want it to look like these guys are doing some acrobatics right around these trees. I mean literally, looping around them. So, uh, let's see. I'll put 'em about there. Let's start with simple selections. I'm gonna use a selection tool that's new to Photoshop, it's called the Object Selection tool, and I'm just gonna draw around this to get it selected. Then I'll hold down the Shift key and I'll draw around the second plane, or the one plane that's here. And I wanna get rid of that one little part, so I'll hold down the Option key, that takes away from a selection, and say, "Get rid of that." Okay, so we got those little parts. But now I want to get the smoke. I'm gonna do that with something called Color Range. It's found under the Select menu right there. But in order to use Color Range, and add to the selection I already have, I need to hold Shift. Shift with selections always means add. So right now, I'm saying add, using Color Range. Now, the last time I used Color Range, it's remembering my settings, I'm gonna try to get it to more of its default settings. When you get Color Range to show up, you move your mouse on top of the image, and you click on what you want to keep, the color you want to keep. Then you can hold on the Shift key, and click on additional colors you wanna keep, and what I'm trying to do is click where we have thick smoke. Wherever the smoke is the thickest, I'm clicking, and I'm doing that in maybe five or six spots, so it sees a variety, the color of the thick smoke. Then there's a fuzziness control, which means 'how much can I deviate from that?' and I'm gonna bring it as high as it will go without showing the rest of the image. So I'm gonna back off on that until the sky is still black. I dunno if you can tell, but this is a preview of our image. If I hold down the Control key, you can see, it's a miniature version of our picture. But as long as this background remains black, we should be fine. I don't care about the bottom. I'm gonna click okay, now we just got a selection of that smoke. So I'm going to add a layer mask, and that's gonna limit what's visible. And so now we have masked our smoke, make it so it looks they're comin' in from the top of our screen, loopin' around there, uh, we could improve it, if we threw this into Select and Mask. Just go Select and Mask, and why not give either Photoshop control over in the edges, just make sure you're on the second tool that's there, and see if it does a better job by painting. If it improves, go for it! Or, what if the color on the edge might look better if Select and Mask did something about it? Well, turn on Decontaminate Colors and find out-- oooh, look at that! Made it much more vividly that color. And then we could continue by painting on the layer mask to limit where this shows up. But in general, you should be seeing that Select and Mask is a big deal. It's what we've been using to refine anything anytime we have furry, fuzzy, or hairy edges. When it comes to advanced masking, there's a lot of techniques that we can use, the better you get at each individual one, the better you're gonna be, but ultimately, it's combining those features together, like when I used the Object Selection tool to select some skydivers and then I held Shift to say 'add to', and I used another feature on top of it. I can further improve it by setting it to Select and Mask, so it's not usually an individual, you know, one thing does everything, it's a matter of knowing all your options so you can combine them.

Class Description


  • Isolate furry, fuzzy, and hairy objects (i.e. animals)
  • Remove the background from transparent objects (i.e. glass)
  • Select objects using Color Range
  • Deal with objects that vary in sharpness
  • Use Select & Mask to refine selections


  • Beginner, intermediate, and advanced users of Adobe Photoshop.
  • Those who want to gain confidence in Adobe Photoshop and learn new features to help edit photos.
  • Students who’d like to take ordinary images and make them look extraordinary with some image editing or Photoshop fixes.


Adobe Photoshop 2020 (V21)

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