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Advanced Layers in Adobe Photoshop

Lesson 3 of 7

Layer Style: Knockout Deep

Ben Willmore

Advanced Layers in Adobe Photoshop

Ben Willmore

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Lesson Info

3. Layer Style: Knockout Deep


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3 Layer Style: Knockout Deep Duration:12:34
4 Blending Options: Blend if Duration:13:18
6 Layer Comps Duration:08:30
7 Black-Only Shadows Duration:06:07

Lesson Info

Layer Style: Knockout Deep

So, I often structure my documents using those groups, and here is a very complex image. But when I open the image you'll see that my layers panel is very easy to understand. That obviously what's in here is my retouching. And refinements for me means adjustments, where I'm just optimizing the image. And then with this particular series of image I do a partial black and white effect which is contained in there. So if I turn off all the eyeballs for these groups you can see the original image. And then I could turn on the eyeball for my retouching to see how extensive of retouching I've done. If I expand the group, I can see that there's a total of three layers. And if you look at them, one's called weeds-b-gone. That's usually my overall retouching. And then here I wasn't certain if I really wanted to in the end get rid of the stuff that was on the right-hand side. But I wanted to try it so I put it on a separate layer so I could turn it on and off. And then I made a separate one for a...

moving, an electronic sign that's on the left side of the picture. And here's the right side of the picture. I wasn't sure if I wanted to do it. So anyway, those are organized. Then, I usually have my retouching directly above the original picture. And if you structure your document that way, above that you can have adjustment layers and everything works out nicely. So here I'm gonna now turn on my refinements and let's see if the image changes at all. Yeah, it seems like the color within various area have been enhanced. And if I open that you can see all the adjustment layers that are contained within. Each one of them is either a curves adjustment layer or a hue and saturation. Those are the two adjustments that I use the most, and that's why we covered them, we covered curves in a tonal and adjustment layers lesson as part of masters academy. And we covered hue and saturation in a color adjustments lesson. So if you have those lessons, feel free to watch and you'll see that those are all stacked. There's so many of them though that I put them in a folder. Then up here we have tinted black and white. And, there I have a black and white adjustment layer that's in this layer down here. And then I have some special stuff going up here, and this is stuff we haven't talked about yet, so that's what I want to dive into, and show you some special settings we can use related to groups. So, if I look here and I turn of the eyeballs in some of these layers, what I have inside of this group that's doing the majority of the work here is a black and white adjustment layer. Now, I could add a mask to the black and white adjustment layer to limit where it can affect the picture. The problem I find is having a single mask isn't versatile enough for me. And oftentimes I want to come back and make additional changes later on, and if all the masking I've done is in a single mask that makes it much more difficult to be able to have the versatility to come back and adjust things later. So let me show you how I have this setup. Here I have a layer where if I hit the backslash key that's right above Return or Enter, the layer mask that's attached to that layer will get overlaid on the picture. So only the area you're not seeing red on is affected by this layer. That layer is what is commonly referred to as an empty adjustment layer. What's an empty adjustment layer? It means an adjustment layer that would not change the look of your picture at all. That would be like going in to do a levels adjustment layer, and just never moving a single slider in levels. Then that would be levels waiting to be used, waiting to have the sliders moved, but not actually making a change to the image yet. Well this one is setup for the trees, and what I wanted this layer to do is to be special. I want this layer to act as a mask for the layer that's below, to limit where it can affect the image. And I want to be able to dial in exactly how strong that adjustment is applied. Well let me show you how that can be done. I'll create a brand new one of these layers just in case you're not completely following what I mean by an empty adjustment layer. And then I'll turn these back on so you get a better sense. So I'm gonna come down here and create an empty adjustment layer. I could use a Brightness and Contrast and just don't move the sliders. Levels, don't move the sliders. Curves, hue and saturation, there are many different adjustments you can use. The actual type of adjustment does not matter, as long as you can get it to not change the appearance of your picture. And that means you shouldn't use a black and white adjustment, because it's not possible to not change your picture using that. It always makes your image black and white. So anyway, here I have a levels adjustment layer. Not gonna touch the sliders at all, so I leave this as an empty one. Then I'm gonna make a selection, or just paint on its mask, however I'd like. So I'll grab this. I'm gonna fill that mask with black. And then I'll grab my paintbrush, and I will try to get this round circle right here. Okay. Oh I gotta paint with white. You're not actually seeing anything change in the image yet, but I am playing with the mask. So when I let go of the mouse if you look in the mask, you'll see I painted with white in a tiny area. If I do my little overlay with the backslash key, that's what I've painted on in my mask. So, how can I get this to act like a mask for the layer that's under it? Well the way I can do that is with a special feature that barely anybody ever notices exists. Here's what it is. I'm working on an empty adjustment layer. The empty adjustment layer has a mask attached to it. I go to the bottom of my layers panel, I click on the letters FX, and I choose Blending Options. And that brings up this screen, full of choices. We're just gonna look at once choice that's contained within here, and it is called Knockout. The default for Knockout is set to None. I'm gonna change it to Shallow. What does shallow means? Shallow means look at the folder I'm currently working on, which is known as a group. And cause this layer, wherever this layer would usually be visible, to poke a hole, or knock out any layers that are below it within this folder. So if I choose knockout shallow, suddenly it's causing a hole to be poked through the layer that is found underneath. And it's allowing it, preventing it from affecting that area. All I did was set knockout to shallow. And what it's doing is looking at this layer and the mask is controlling where would this layer usually show up. Only where it's white in the mask, so that little part. So then I could create another one of these. I could come in here and let's do another levels adjustment layer. Not gonna move these sliders at all. And I'll fill the mask with black, so it usually wouldn't apply anywhere, and I'll choose a different area to come in here and paint on. Here, I'm gonna come in and with my paintbrush painting with white, I'll go on the pump. And I'm not being precise right now, but imagine I was. Then I'm gonna take that layer, go to the letters FX, choose Blending Options. And say, let wherever that layer would usually be visible, that's where there's white in the mask, make that knock out, and shallow means only through the contents of this folder. So it pokes a hole in it. And I can continue painting on the mask. Maybe I paint up here. There we go. So now I can have more than one layer that's poking a hole through that black and white adjustment layer. Well what I want to frequently do is I want the black and white adjustment layer to partially apply to areas. Just not at full strength. So now what I can do is click on either one of those adjustments, and go up to the opacity setting at the top of my layers panel. And I'm just gonna lower it. If I brought it down to zero percent it means it's gonna affect the image zero percent of the way. But if I bring it up a little bit I can now make it so I'm controlling how much is the black and white adjustment layer able to affect this area. So I'm gonna throw those two adjustment layers away that I just created, and show you the ones that were already in here. So, if we look at the first adjustment layer that was here, if I overlay the mask, you notice the area that doesn't have red in it is where there are trees. Trees both in the left side of the photograph and trees you can see through a window in the building. And, if I turn the eyeball on there, that is causing the black and white adjustment layer to apply 73% of the way to those areas. So they're almost black and white. How do I know it's 73% of the way? Actually it's 63% of the way. Because it's the opposite of whatever this number is. This is how much we're preventing that from showing up. So we're removing 37% of the adjustment. The next one is this area. And that's where I want your eye to be drawn so I want that to be the most colorful area in the photograph. And so that one if I turn it on is set to 100%. That means block 100% of the black and white adjustment. Then, there is here, and I see on the building there's just some stars and those little lights that are above it. And that one is set to 77%, because I just didn't want it to be quite as vivid as the areas where I wanted your eyes to go to. Then we have one that is of the station itself, and that is set to 53%. So about half amount can apply to the station. So by stacking a bunch of empty adjustment layers, adjustment layers that wouldn't change the look of the image at all, I can use the masks that are attached to them. And if I set the layers to knock out shallow those masks are knocking a hole in this black and white adjustment layer, and I can isolate various area within the photograph, and then adjust the opacity of each one to control how much of the black and white adjustment layer is prevented from being applied. And so this is something that I do that is a very advanced use of layers to give me much more versatility. And in this case, have four separate masks that are controlling where that black and white adjustment layer applies to the image. The key to it is that when I go to the letters FX and choose Blending Options, that this right over here is set to Knockout Shallow. So then that begs the question, what does Knockout Deep do? Knockout Deep will knock through all layers that are contained below this layer that's set to Knockout Deep, until it hits a layer called Background. And so if I set this to Knockout Deep, and I up the opacity to 100%, it's at 53 right now, there is not a layer in my document called background. And so it just knocks a hole all the way through the bottom of the document. If the bottom most layer within the document was a background, then it would have knocked through until it hit the background. And so, that's an advanced feature in layers that I love using, but I showed you it's mainly Knockout Shallow, because I'm usually trying to knock through things that are contained within a group. I'm guessing not everybody will use that one, but for those of you that do, I think it'll bring you to another level with what you can do.

Class Description


  • Add dimension and shadows using Layer Styles
  • Link multiple layers so they will always be scaled and transformed at the same time
  • Organize complex documents using Groups
  • Quickly remove the background on clouds, lightning, and logos
  • Cause bright or dark areas to disappear using the Blend If sliders


  • 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)