The Pass Through Blending Mode
Okay, so this actually not a complete version, but almost a complete version of one of my composites. The final version had a little boy riding the bear there. Does anybody here subscribe or follow Photoshop User Magazine? No? Alright. Well, this was on the cover of Photoshop User magazine about a year ago and it did have the little boy on top, so this whole time we've been talking about layers and how blending modes work with layers. Now, just a second ago it was on screen, I just moved it, but does anybody know what the default blending mode for a group is? It's not normal. No? Okay. So the default blending mode for a group is pass through. Groups are used for organization, so you have a whole bunch of layers in a composite, and you can just select them all, press Control + G, Command + G on the Mac, to put them into a group, and that's it. They are used to organize things. However, if we change the blending mode, they become more powerful. So by default, they're just there to hold l...
ayers and let them pass through, let them go down like any other layer. But if we are, as I said, with compositing they become more powerful. Before I show you exactly what I mean by that, let me pose a problem to you and then I'll show you the solution with group blending modes. So I have one bear layer, this bear layer here, that bear, and I'm compositing and I'm thinking, you know what? I think he needs a friend. So I'll press Control + J, Command + J on the Mac, to duplicate, and now he has a friend. You have two bears. But then I decide, you know what? I need to make an adjustment to these bears, and obviously I want to work non-destructively, so I will create a curves adjustment layer, and I'm just gonna make an extreme adjustment so that it's noticeable. So it's not really, it's not meant to look good, it's meant to be noticeable for the class. So now I made that adjustment to that bear, but since they're really twin brothers or sisters, I want that adjustment to also be on that bear, so how do I, how do I do that? I can duplicate the curves adjustment layer, of course, so I can press Control + J, Command + J on the Mac, to duplicate the curves adjustment layer. I can bring it above the other bear layer, press Control + Alt + G, Command + Option + G on the Mac, and there you go. I've applied the effect to both bears. The problem is, now that I have two of adjustment layers that are really doing the same effect, if I later decide to change the effect to something else, I have to do the exact same adjustment to the other adjustment layer. And I know what some of you are thinking, well why don't you just create one adjustment layer, and instead of having it clipped, create a layer mask? Another tip for you, if you hold Control, Command on the Mac, and you click on a layer thumbnail, it would load the active pixels as a selection, so I'm gonna hold down Control, Command on the Mac, click on the bear layer, it makes its selection out of the bear, hold Shift + Control, click, and on the second layer to select the second bear. I'll delete my layer mask, oops, I disabled it, not deleted it, and create a layer mask. So now, that layer mask is holding the two bears, and that certainly does the job. We have one adjustment layer that's controlling both bears. The downside is that if I later decide to move one of the bears to a different position, the adjustment doesn't move with it because the layer mask doesn't move. You would have to redraw the layer mask. Now, you may be thinking, well, that's not really that big of a deal, it's only one adjustment layer, but what if you have five or six or seven adjustment layers controlling those objects? You don't want to both duplicate them, or create a whole bunch of layer masks just to control one object like this, or two objects, or maybe there's even three or four bears, or whatever the number is. Anyway, so, I think the problem is clear. How do we use an adjustment layer, multiple adjustment layers, apply an effect to multiple items in a composite and have them both be editable, and have the flexibility to move them anywhere you want? What you can do here is put the bear, or whatever the object that you're working on with, into a group. So Control + G, Command + G on a Mac, group one, pass through. Everything in there is passing through. Then, I actually deleted the second bear but I do need it, so I'll add a second bear, move him here. Then I can make my adjustment, whatever that adjustment is. So again, I'll make it extreme so that it's noticeable, I made my adjustment to the bears, but I don't want the adjustment to effect the background, just the bears. Well, I could simply change the blending mode from pass through to normal. Oops, that's the wrong group, that's why it didn't work. It has to be, let me change that back to pass through, go back to this group, the group where the bears are in, pass through to normal, now that adjustment layer is only effecting the contents of the group. Okay, see that? So now, I can move the bear anywhere I want, the effect is a applied. If I want to add more bears, I can add more bears. No matter how many bears I add, that effect from this curves adjustment layer is applied to all the contents of the group. I can even apply more adjustment layers, so maybe I apply a hue saturation adjustment layer, change the color of the bears. Apply a, let's see, maybe we can do, I don't know, vibrance is to have more vibrance and saturation. It doesn't matter how many adjustment layers we add, the adjustment layers are always going to effect the contents of the group, just by simply changing the blending mode to normal. So that's how we overcome that problem that I posed in the beginning of the section. Now, just to give you a little background of what's really happening behind the scenes, is that the pass through blending mode simply says whatever goes in this group is just like any other layer, it just goes through. If you change the blending mode to normal, or anything else, that's the equivalent of pressing Control + E, Command + E on the Mac, while you have a group selected to merge those into a group. So notice that I pressed Control + E, Command + E on the Mac, and it merged them into a group. The blending mode is normal, and it looks exactly the way that it did when it was still a group set to normal. So for example, if I select this group, change the blending mode to something like overlay, then press Control + E, Command + E on the Mac, still set to overlay, it's the same thing. So basically, it merges all the contents of the group first, then it applies the blending mode. So when we were compositing the group was merged, so it applied all these adjustment layers to the layers inside of it, the bears, it apply it to the bears, so that's how we got that effect. Once we changed the blending mode to normal, then in Photoshop's mind, it became one single layer, and you got the effect inside of the group just by using the adjustment layers in the bears without having to create any layer masks or anything, because, again, when the blending mode is changed from pass through to normal, it just basically becomes a flattened layer, but in reality it's not. It's still a group, so that's one good way of using adjustment layers in your compositing to effect multiple things inside of that layer.