Join Deke McClelland for an in-depth discussion in this video Introducing masking, part of Photoshop CS5 One-on-One: Mastery.
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All right gang! Over the course of this project we are going to take this woman with her swinging hair and we are going to composite her against a totally different background and we are going to do so using masking. Now, masking is ultimately the art of using the image to select itself. So, you're taking the luminance levels and transitions that are inherent in the image across one or more channels and you're exaggerating those differences in order to create the final mask. So, for example where this image is concerned, and I'm working inside of Hair in flight.tif, found inside the 26_masking folder.
It comes to us from photographer Stas Perov of the Fotolia Image Library. If I go to the Channels panel, which I invite you to do as well, you'll notice in addition to the color bearing channels Red, Green, and Blue, I also have a couple of Alpha channels, non- color bearing channels inside of this image. One is called basic mask and the other is called tougher mask. Now, basic mask takes about 15 minutes to put together, tougher mask takes about a half an hour. We are going to go for tougher mask and it's going to take us more than a half an hour of course, because we're going to be discussing each and every step as we go along.
However, the reason we are going for tougher mask is because, A) this is the Mastery portion of the series, so we ought to do the absolute best work we can I figure, and it will give you a sense for the myriad approaches to masking inside of Photoshop. But, bear in mind ultimately at the end of the day we want her to be white because that indicates the area that will be selected or opaque or what have you. Then, we want her background to be black because black indicates deselection. It also indicates transparency where we would express this Alpha channel as a layer mask.
Now, I am going to switch back to the RGB composite image for a moment so that we can check out what we have to work with in the first place. What we're looking for is contrast, we want as much contrast as possible. You might figure well we've got that, right. We have these very dark hairs against a lightish background. Well, that's part of the problem. It's lightish. It's not light. In fact, it's a gradient. So, we have some areas that when you look at them they stand out as being bright but they're not all that bright.
It's pretty dark gray back there and it gets awfully dark gray in some other areas. Meanwhile, her hair kind of varies all over the place in terms of its darkness. It's very dark in some locations and quite light when it gets out of focus, when it's in movement, when we only have a few strands of hair to work with. Also, note that there are no color differences going on inside the hair. We're seeing uniformly low saturation color values going on. So, these blue gray hairs fading into a blue gray background, so we can't exploit the differences between the channels very well.
We can exploit the differences between the channels where the flash is concerned because she's fairly warm, not super warm, but fairly warm against this cool background. However, she is also alternately light and dark and in focus and out of focus. So, the top of the left arm is lighter than its background. The bottom of that left arm is darker. This portion of the arm right there is pretty similar actually to the background as we'll see, because we have to evaluate this image on a channel-by-channel basis.
The right-hand arm is out of focus so we have some blurry details to work with there. Then, there is the dress which is thoughtfully exactly the same color as the background. So, that's quite a problem. Now, you might once again, look at this image and say well the good news is it's a plain background. The photographer at least was thoughtful enough not to shoot the image against a bunch of wicker or something along those lines, you know scaffolding or ladders or anything that would be a jumble of detail. And that would make our job that much tougher. That's for sure.
Just know, that the techniques I am about to share with you work with those kinds of images as well. It just gets mind-numbingly boring is basically what it comes down to create those kinds of masks, it's an awful lot of work. Anyway, let me give you a sense of two different final results here. I'll go ahead and switch to Basic mask.psd, also found inside the 26_masking folder. Notice that it's a decent composition. I don't necessarily believe she was actually photographed against this sky. However, that's okay.
It's all right if we have an unreal composition. What's not okay is if it's not professionally executed and this one is. Now, we do have some halos going around some of the finer hair details. That's actually pretty natural, by the way, if you take a look at a few hair shot you'll see those kinds of halos around the hairs. So, that doesn't bother me. What bothers me a little bit is that I had to throw a lot of hair detail away. So, we are losing some hairs over on the left-hand side and her hair is thinner over on the right-hand side than it was inside the original composition, which is why we are going to go for a different effect.
We are going to go for an effect like the one in the Elaborate composition.psd file, again found inside the 26_masking folder. This time we have a lot more hairs over here in the left-hand inside and a lot thicker hair coverage over on the right-hand side. So, I'll show you those two images again. This is the more basic version of the mask and it's a more basic composition as well. It doesn't contain that many layers. This is the more elaborate version of the image. It takes longer to create the mask in the first place and if you switch over to the Layers panel you'll see that we have a lot of layers going on as well.
What I am going to tell you is you can go either way. So, you could decide, gosh! You know you don't have enough time to pull off this kind of elaborate composition right here. So, you are going to stick with this one because it's good enough, the basic mask effect. And it's only going to take you once you come to terms with things, this is like a 15-minute mask. If you want to see it documented, by the way, I document the creation of this very mask inside of another series and it's just three movies, so it's a quickie if you want to check it out. Photoshop Top 40 is the name of the course and it's a countdown, so the various features appear in opposite order.
So, we've got 33, Calculations first, then 32, The Pen tool, then 31, The Brush tool. You watch those three sequential exercises and you'll see exactly how I created this effect. However, in this chapter we are going to for the more elaborate composition and for a couple of reasons - first of all, this is the Mastery portion of the series so it seems incumbent upon us to do the best job possible. Also though, I'm going to pass along a few additional techniques which you might find useful. Some stuff I developed specifically for this project, in fact. So, we'll get into it and we'll see how Alpha Channels work beginning in the next exercise.
Recommended prerequisites: Photoshop CS5 One-on-One: Fundamentals and Photoshop CS5 One-on-One: Advanced.
- Using masks and blend modes in radically new ways
- Mastering the Pen tool and Paths panel
- Transforming and maximizing Smart Objects
- Employing Smart Filters to create complex effects
- Exploring the capabilities of Bristle brushes and the Mixer Brush
- Merging multiple images into seamless panoramas
- Exploring the full range of luminance with HDR Pro
- Recording actions and batching-processing images