Contrast Blending Modes
I'm gonna go to the contrast category. The contrast category is the blending modes from overlay to hard mix all these guys here. And they all have one thing in common-- 50% gray becomes invisible, except for the very last blending mode which is hard mix. But you probably won't be using hard mix too much you'll probably be using the other ones the most. And the contrast category is sort of a combination of the two previous categories. It looks at luminosity of the pixel. If it's darker than 50% gray it applies a darkening effect, if it's brighter, it applies a brightening effect. So, once again, I'm gonna double click on the color picker and if I click and drag here you'll see all the different shades of gray. And if you look at the brightness right here, the B, 100% is white, 0 is black, and right in the middle you have 50% gray. So that shade of gray, 50%, becomes invisible with all these layers or I'm sorry all these blending modes. So if I come back into my luminosity layer here, 50...
% gray is this big box here and the one in the center there. If I change the blending mode to overlay which is the first blending mode in that category, you'll notice that on the left hand side, we applied a darkening effect, on the right hand side we applied a brightening effect. Nothing happened to that box here in the center because it was 50% gray so it became invisible and there's a gradual transition of darkening and brightening effects on the gradient there. So its a good way of applying contrast to an image or doing other sorts of things. And actually one thing that I didn't mention earlier is one thing you can do with blending modes is simply create any adjustment layer. It doesn't really matter which one. Any adjustment layer, actually it does matter which one. Some adjustment layers won't work for example it wouldn't work for color look. But basically any adjustment layer right here that controls luminosity so brightness, levels, curves, exposure. If you create any one of those, in that case I created the curves adjustment layer, I can simply change the blending mode. I don't have to do anything else. And it will apply a darkening effect in the case of multiply or a brightening effect in the case of screen or a little bit of both in this case, in the case of overlay or any other of the blending modes. So basically what it's doing here with that adjustment layer is exactly the same thing as duplicating the layer and changing the blending mode to multiply screen or overlay. But if you ever do that the file size becomes bigger so it's better to use an adjustment layer like the curves adjustment layer or I could've used levels. And then just change the blending mode. So we have an image that's not dark enough, change it to multiply reduce the opacity, and that's a good way of making an image darker, brighter, or adding a bit more contrast, just by using an adjustment layer and those blending modes. The example that I want to show you in this category is the dodge and burn example for those of you that are photographers you probably know this technique. If I create a new layer, I can fill it with 50% gray so that it becomes invisible, and then I can selectively make parts darker or brighter to change the shape of the face or fake the lighting of the scene. Let me show you how to do that. If I go into the edit menu I can go into the fill dialogue box. Another way of getting to the fill dialogue box is by holding shift and backspace, that's what I prefer to do I think it takes too long to go into the edit menu. Within the fill dialogue box you can select black, white and 50% gray, there it is 50% gray. I can even change the blending mode but I'm not gonna do that now I'm gonna do that on the actual layer. So I have my 50% gray layer here and I can change the blending mode to overlay. The layer becomes invisible. Now I'm gonna make some parts darker and other parts brighter. To do so, I can use one of two tools. Right here in the tools bar I have the dodge tool and the burn tool. The dodge tool makes things brighter, the burn tool makes things darker. And I'm actually gonna change it back to normal so that you can see how that works. So I have my dodge tool selected and I'm making the brush size larger by using the right bracket key on the keyboard. The bracket keys on the keyboard increase and decrease the size of your brush. So I can start painting, see how it's making that brighter when I paint? And I'm actually gonna change the range to the midtones that way it doesn't create such a strong effect right away. So then I can build to brighter pixels. And the burn tool does exactly the same thing. I'm also targeting the midtones but it does the same thing, it changes the luminosity of the pixels but in this case it makes them darker. So I'm making the pixels darker here. So that's what I'm gonna do. But, I'm gonna first change the blending mode to overlay and I'm going to start sculpting the model's face. Initially you wanna do this while wacom tablet or any other type of stylus or pen, I don't have one with me here. The reason that you want to do that is that you can use pressure sensitivity to fine tune your brush strokes. But a mouse would work in this example. So what I'm gonna do is simply just make this side of his face darker. And by the way I'm applying an extreme effect so that it's noticeable, usually I wouldn't want to have these hard shadows there that look really ugly on his face but I'm making them that dark so that you can see them really easily. So I'm painting the side of his face there, making it darker. And I'm going to do the same thing with the dodge tool to make those areas brighter so you can see the before and the after. So you can see how we apply that lighting effect to the photo. And obviously you can reduce the opacity if need be. Another trick that I use a lot in compositing with this technique is that sometimes where you're putting images together you are forced to work with an image where the light source is coming from one side but in your composite it's coming over from a different side so it really doesn't look realistic. When you're compositing images together, you want the light source to always be coming from the same direction on all your pieces so something that I do in composites where I'm forced to use a photo that doesn't have the right lighting is actually use a dodge and burn technique to sort of fake it and make it seem as though the light is coming from the other direction. And it really works the same way as what I just showed you. So I'm gonna fill this layer with 50% gray, change the blending mode to soft light, and I'm gonna make the left side of his face brighter. Notice that in this photo the right side of his face is darker so the light's coming from the left. So I'm gonna fake it and make it seem as if the light's coming from the right. It's not gonna be 100% realistic but I think that you'll get the idea once I'm done. So I'm making the left side of his face brighter and again I'm probably going a little too fast here but I don't want to spend a ton of time working on the fine details but you'll get the idea once I'm done. Then I'll make this side darker. (mouse clicks) and I really gotta work on that highlight there just to try to remove it as much as I can. I think this might be good enough to see what I'm talking about. So that's before and after. You can kinda see how the light seems like it's coming from the other direction. Obviously with a little more time and a little more detail I would go in there and work on the actual facial features to try to fake that light coming from the difference source. So that's a little trick for you for those of you that are doing compositing. Sometimes you're just forced to work with certain images and this is one thing you can do to try to fool the eye and make it seem just a little more realistic. But in the ideal situation you wanna have the light source coming from the same side on all your different pieces in a composite.