Making a knockout layer

show more Making a knockout layer provides you with in-depth training on Design. Taught by Deke McClelland as part of the Photoshop CS5 One-on-One: Fundamentals show less
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Making a knockout layer

I've gone ahead and saved my progress as Real Na'vi blue.psd. Certainly there aren't really any real Na'vi, but if there were, this would be the real blue color of their skin. However, the hair is not rendered properly at all. And what we need to do is cut through all this blue down to the layers below. If I click and drag across these eyeballs, like so, to turn off all those blue layers, then you could see the hair looks great without the blue, but with the blue if I go ahead and turn them back on, the hair is a big mess.

It's not the right color, and it's way too dark. That's why we need to cut through these layers down to the layers below using what's called a Knockout layer, and I've already created the knockout. It's this layer that is called haircutter and if you turn it on, you will see this layer of redness here, and I've just set it to red so we can easily see it against the blue skin, and I've both masked away the background and meticulously painted away some of these hair details. So I couldn't altogether come up with an automated means of masking the hair, so I did have to do some handwork with the Brush tool, incidentally.

And that probably took something like a 20 minutes to half an hour of my time. So it was a little bit time consuming, but it was well worth the effort, as you're about to see. So what I'm going to do is I'm going to click on haircutter, and then I'm going to drop down here and Shift-click on blueness, and that will select this entire range of layers. Then I'm going to go up to layers panel menu, click on that little icon, and I'm going to choose this command right there, New Group from layers, and I'm going to name this new group, which is going to be a folder that contains these layers just like this little folder called eye layers there.

I'm going to call it, the blue, like so, because it represents the blueness inside the image. And then I'll click OK in order to create that group of layers. Now to see the layers inside you click that little twirly triangle in order to expand the group. Now I'm going to drop back down to haircutter, and we're going to turn it into a knockout layer that bores all the way to the bottom of the group, so that we're going to expose everything that's outside the group behind it. And you do that by bringing up that Blending Options function again.

So go to the layers panel menu icon and choose Blending Options, or if you loaded dekeKeys you can press Ctrl+Shift+O or Command+Shift+O on the Mac, and you want to set this Knockout function right there to Shallow. If you set it to Deep you're going to bore all the way down to the background layer, so you're going to cut through those liquified layers. Liquify eyes and brow & nose, you may recall those. So you don't want to bore that deep. You just want to go down to the bottom of the group. So choose Shallow. Now initially that doesn't do anything.

We're still seeing all the red there. We need to turn everything that's opaque on this layer, kind of weird logic, but we're going to take everything that's opaque on this layer, all the red, and turn it into a hole cutting force. Anything that's transparent on this layer, which is the stuff that's not red, won't do anything. And you do that using this Fill Opacity value. Not Opacity, but rather Fill Opacity, and notice as I take it down, we lose the red, and we start regaining the hair in the background and pretty soon when I take this value all the way down to 0%, we're cutting all the way through the blue to the hair.

And so I'll go ahead and use this Preview check box right here to show you the difference. This is before the application of the knockout, and this is after. Now let's get a sense of what kind of contribution that knockout layer is making. I'll go ahead and click on OK, and this is what the image looked like before we added the knockout layer, very dark bluish hair, and this is what it looks like now, thanks to the application of a fairly complicated but very successful knockout layer. Now having done that, I'm going to go ahead and twirl that blue group closed again, so that we're just seeing the effect of the layers inside that group as well as brow & nose, liquify eyes, and Background.

We've made a lot of progress, folks. We've gotten her skin down. We've got her hair detail down. We still need to work on the eyes, the warpaint and the background, just as we will in future exercises.

Making a knockout layer
Video duration: 4m 11s 17h 33m Beginner


Making a knockout layer provides you with in-depth training on Design. Taught by Deke McClelland as part of the Photoshop CS5 One-on-One: Fundamentals

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