Working with masks and calculations in Photoshop

In the days of the Dark Room. It sounds like we're talking about, you know, the 19th century or something, which I guess we were. But, it went well into the 20th century. Anyway, back when people worked in Dark Rooms, they had to spend a lot of time developing dodging and burning skills. This was a kind of critical eye-hand coordination that they had to get to be able to make selective edits. Hi, I'm Ben Long, and this week on The Practising Photographer we're going to look at some Digital Masking skills. The equivalent of dodging and burning in the dark room era. And just as important now because even with the great cameras we have.

And the fantastic post-production that we have still, what can save an image sometimes is the ability to make a selective edit, to lighten or darken just one part of the image or the other. In a case like this, where I went to edit this camel, separately from the background, I ran into a problem because this camel is all furry. The edges of it, has a little hair and things and if you've ever tried to mask around that. You know that it can be very difficult. It was much harder in the Dark Room when you had to do that with dodging and burning, this a capability that we have in the Digital era that didn't exist before. Never the less, it can still be tricky unless you've got some of the tools that Photoshop introduced around CS 5 or so, the Refined Edge Command, and I want to show you that really quickly.

And then go into something that, I don't see a lot of people doing. Which is using the calculate Dialog Box to build complex masks that really allow you to gain a lot of control over your selective editing. So what I want to do is darken the background. The camel is up against this bright sky. Tonally the camel and the background are not that different. I think I can make an image that has a little more depth to it, a little more drama if I darken the background separately, I'm taking the quick select tool here. Which is a combination of a magic wand and a paintbrush. And I'm adjusting my brush size with the left and right bracket keys.

And I'm just painting over the camel. And as I paint, it does this kind of little localized magic wand thing, and it's starting to select the Camel. I find with the Quick Select tool it's best to make small strokes and then stop, rather than try to paint the camel all in one stroke. Invariably when you do that it goes and grabs other things in the image. So I'm just making short strokes here, and letting it figure out the rest. I'm not worried about these strokes creating a perfect mask. I'm going to go in and improve the mask in a, in a little bit. I just need a rough selection of this camel here.

This of course is a Bactrian camel, I know that because it has two humps rather than one. The one humped camel would be the Dromedary camel and as I'm sure you know the Bactrian camel is native to central Asia; the Russian Step rather than the, yes this is the camel education section of the video here. I just need something to talk about while I was painting, I knew it was going to take a while. So incase you are wondering do I really just sit around and learn about camels? No I just looked all that up on the Wikipedia I shot this is southern Siberia a couple of months ago.

Alright I mostly got this where I want it. There are a couple of things that need to be picked up here that I'm not going to worry about except for this little bit of his tail. There's probably something important to say about the tail of a Bactrian camel but I don't know what that is. So there we go. You can see that I've got generally the camel selected. I don't have stuff selected up here on the humps. I don't have really any of his fur selected. I can actually do a little bit better job there. Something that happened earlier that, I didn't call out cause I was too busy telling you about Bactrian camels.

I accidentally selected this part, so I don't want this area between his front legs, if I hold down the Option key, I get the ability to remove things from a selection and I do that just by painting over them. So I'm just using the Quick Select tool in combination with the option Quick Select tool or Alt if you are on a PC to select thing, things. So, now I have got a pretty good camera mask there, except it's going to look lousy around all this hair stuff. I am going to the Select menu and choosing Refine Edge. This is going to let me really improve the edges of this mask.

First thing it does that it drops out the background or it drops out everything on the outside of the selection it just shows me white. I can change what I want in the background. I'm just going to stick with white, that's fine here. The key to this particular problem lies right here in the Edge Detection part of this Dialog Box. I'm going to check Smart Radius and dial my radius up here to about one, maybe a little less, maybe a little more. I'm never that picky about it. And I'm going to grab this paintbrush right here. Now, all I have to do is paint along the troublesome parts of the edge here, like this furry bit right here.

I'm just going to paint along the boundary there and when I let go of this brush, Photoshop's going to think it over and reassess it's idea of where the edge is. So, basically, what I'm doing with this brush is just giving Photoshop some hints. I'm saying, oh mighty Photoshop right here is an edge, could you go back and do a little bit more calculation on that and it does and the calculation is good enough that it can put in these difficult bits. Soft edge fur, and it does a spectacularly good job.

One thing about this kind of mask particularly on a background like this I, I have a great advantage that my background. Is very totally similar to my foreground is, even if this mask isn't perfect, even if I don't have every tiny little bit of wispy hair, it's not going to show. Because a lot of the troubles in the mascot is going to blend into the background. And all I need is just enough of the wispy hair to indicate or to it imply a furry edge, I'm going to be fine. I could go and paint around the entire thing I don't think I'm going to have to because a I, I really only need to get the parts with fur these bits here where the fur is more matted down are going to look okay.

Now, of course, if I was masking a Dromedary camel it wouldn't take as long, because as you know, there would only be one hump, but this being a Bactrian camel I do have to do both, and the other real problem in here is going to be the tail. It was the area that was really full of a lot of separation of individual, individual hairs and things. And as I'm painting Photoshop reveals the areas that, areas that I had not even selected. So this tool is very forgiving in that way. I don't have to have my initial selection dead on.

You can also see that I'm painting pretty sloppily here. And it's still working out okay. If I end up painting in more detail then I like. I actually have the ability to pop this open and change to erase refinement. That would allow me to restore the edge to where it was originally. I think this is really good. I think it's all chewed up here. I'm, oh, oh, I'll go over it anyway. I'm not that worried about the, the, not that worried about this area, because again, it's mostly the same color as what's in the background. So I'm going to hit OK, and rather than actually knocking out the background, it does something much more useful. It just gives me a selection.

The camel is now Selected. I want to Save that selection, so I'm going to my Channels palette. And clicking on the Save Selection as channel button and here in my little alpha channel Thumbnail you can see a nice white outline of a camel. So I think this is probably pretty good. What I need to do now is use this mask to darken the background. The camel is currently selected not the background. So I'm going to invert my selection Select Inverse or Cmd+Shift+I. So now you can see I've got marching ants around the edge of the screen.

The selection on the camel didn't really change, because it's just the inverse of the selection, and the edge of the camel is still the boundary. Now I can go to my Layers palette and make a new Levels Adjustment layer. If I make an Adjustment Layer with a selection currently in place. Photoshop automatically builds a Layer Mask for that Adjustment Layer out of that selection. So, I've already got a mask in place so now I can simply throw in some darkening. And as you can see, the background is getting darker, the camel is staying the same.

So I get this very nice mask here. Look at the hair. It's a very clean mask all the way around. Obviously I don't want that extreme, I'm just going to move my black point over here to the edge of the data. I think I am going to take my midpoint and shift it a little bit. What I'm mostly focusing on here is this area in here. And this is the part where there wasn't enough total separation between the foreground, and the background. I like this stuff darkening up. Let me close this, turn this off. Here's before, here's after.

Getting a lot more depth in here it's really bringing out some highlights, and some of those lighter bits in the grass. I like that a lot. However, the sky has darkened up too much, it's kind of an unbelievable shade of dark. When I shot this, I, I knew that there were these telephone lines back there but there was nothing I could do about it. I can go in and paint those out later. I kind of like them now, I might keep them, I don't know. It looks like a musical staff or something. But anyway that's, that's an edit separate from any of this masking. I do know that the sky is too dark. Now normally to darken a sky I would use a gradient mask on a levels Adjustment Layer.

This would be a mask that would lighten the sky up here, I'm sorry I said, darken the sky earlier. To edit the sky it would apply and Edit the top and then ramp it off down at the bottom. And the way I would do that would be to create a levels Adjustment Layer. Lighten my sky up here and then take my Gradient tool and simply do this. So now with my mask in place you can see I have this ability to Edit the sky separately from the ground. Unfortunately it's also editing the camel, and if you look at my mask over here.

You see this perfect gradient over here. What I need is a combination of this gradient and my camel mask. And that's what I'm going to use, the calculations or calculate Dialog Box four. I'm going back to my Channels Pallet and I see here that I have my Alpha one channel, which is my camel mask. I'm going to make a new channel, by clicking this new Button down here, and I want to create a gradient in here. The problem is now I can't see my image, so I don't know where the Gradient needs to be. If I just turn on one of my color channels, that will show up as a reference. So I'm still editing my Alpha channel down here.

With my Gradient tool selected, clear this out of the way. So I've got this mountain range right back here. I think I probably want my Ramp to start about here and, and here. So here you can see my Mask is open at the top closed at the bottom with this nice gradient in the middle unfortunately it includes my camel, that's okay. I'm going to go back to my RGB, normal RGB display here and what I'm looking for is calculations, which I've now lost track of.

Image, there we go. Image calculations and this Dialog Box comes up. Don't worry about what's going on here because it's not configured right now. I don't worry about the layer that I'm working in. I want to just pick the appropriate Alpha channels, so I want to start with Alpha one, which is my camel mask, and I'm going to merge that with Alpha two. And if my blending mode is set to subtract, what's happened is it has subtracted alpha one from Alpha two, so I have my Background wide open. The camel's all knocked out in front of it, with the beautiful edge that I created before.

My foreground is all closed off. I think this is going to be a really nice mask for doing the edit that I want. I hit OK, and I end up with this mask down here. Back to my RGB view. So what I need to do now is, load this as a selection. That's very easy. I click and drag it down here to the Load Selection button and I get this mess. I can now just do the same thing I did before and create a new Adjustment Layer and it's going to automatically build a mask for what I need and now, if I come in here, this is not the edit that I wanted, just want you to see that my mask is working and darken, you can see that the sky is getting darker, the camel is not, not is the foreground.

So, my mask is working just fine. Now what I can do is just lighten the sky a little bit, just take a little bit of that extra dark edge that wasn't supposed to be there in the clouds. It's also removing a little bit of the blue cast. So let me give you a before and after. Here's before, here's after and that has not edited my camera at all. So calculations is the key to creating really complex masks where you need gradients in one place, selections made with other tools in another place It's very easy to use. Sometimes you have to play with the Blending Mode there a little bit.

Subtract or add is going to be the right option depending on the order that you put your masks in. Refine edge, meanwhile, is the key to getting these nice soft edge masks. If you were going for that Richard Abaddon look where you shot someone in front the wall, and you want to knock the wall out and just have white behind them. That masking technique that I used on the camel, is going to be what you're going to do to do that it's the key to getting a good mask around hair.