Join Jan Kabili for an in-depth discussion in this video Making geometric selections, part of Photoshop CS4 Essential Training.
Making a selection is the way to isolate part of an image in Photoshop. Why would you want to isolate part of an image? So that you can work on just that area without affecting the rest of the image. Before we start making selections on this file I'd like to show you a couple of examples of why you might want to make a selection. Let's say that you were working on this photograph and you decided that you wanted to make the sky more contrasty but you didn't want to affect the color of the buildings. The way to do that is to first make a selection of the sky and then correct the contrast. Or let's say you're working on this file and you want to change the color of the yellow balloon but leave the color of everything else the same.
The first step is to make a selection of the balloon. Or let's say you have this shot of a water tower but the background has that white sky look that just isn't very appealing. So you want to take the water tower and its plants and put it against a more vibrant background. Yes, you would select the water tower and the plants even though that's a little more difficult than the other files I showed you, and then drag the water tower into another image. In this chapter I'll show you how to make all of the selections I just showed you, but first, let's go back to basics. You'll learn in this chapter that there are lots of Selection tools and features available to you.
The trick is knowing which of those is best suited for a particular selection. We are going to get started by looking at the tools that you'll use to make geometric shape selections, like squares, circles and most importantly shapes made up of straight lines, and that includes things like triangles and polygons and irregular shapes too. So how do you make a selection in the shape of a rectangle? I'm going to the toolbox and I'm going to click on the first of the Selection tools here, which is the Rectangular Marquee tool, and to make a rectangular selection all I'm going to do is come over to the image, click and holding the mouse down I'm going to drag and I'm dragging diagonally to the other corner of this rectangle and releasing my mouse.
These animated lines that you see are the boundaries of my selection. These are called the marching ants. Now what if I decided I don't want this selection? Then I'm going to deselect. The way to deselect is to go to the Select menu at the top of the screen and choose Deselect. This is something you're going to do all the time so it's worth remembering the shortcut, which is Command+D on a Mac or Ctrl+D on a PC. And by the way while I have this menu open, take a look and you'll see that there are lots of different commands here that are related to Selections. So if you're looking for a selection related command at any time, this menu is the place to go.
Now if I do want to deselect using that shortcut I'm going to press the Command key and the D key at the same time, Ctrl+D on the PC. And now I want to show you how you can constrain a rectangular selection to a square shape. To do that I'm going to hold down the Shift key on the keyboard and then I'm going to drag and then the portions of the selection will stay in the shape of a square no matter how big or small I make the selection. Now what's important here is to release your mouse before you release the Shift key. I'm going to deselect this selection by pressing Command or Ctrl+D and now let's talk about how to make a circular selection.
That requires a different tool, one that's hidden behind the Rectangular Marquee, so I'm going back to the toolbox and I'm going to choose Elliptical Marquee tool. And I'm going to come over and make a selection around this red circle. First I'll just draw an oval to show you that you can click-and-drag and make an oval in any shape or any size like this, Command or Ctrl+D to delete that selection. If I want to make a circular selection constraining that oval I have a couple of ways to do it. One way is to hold the Shift key down as you drag and that constrains the circle. But I actually don't like to do it that way, because in order to make the circle fit right on top of that red dot I have to use my free hand to hold down some other keys on the keyboard as I'll show you in a minute.
So instead Command+D or Ctrl+D to deselect I'm going to go up to the Options Bar for the Elliptical Marquee tool and I'm going here where it says Style and I'm going to choose Fixed Ratio. That fills in the Width and the Height with a one-to-one ratio, which is the ratio for drawing a circle. So now I'm going to come down into my image, I'm going to start with my cursor at the top left of the red circle in the photograph. This time I don't have to hold the Shift key. I'll just start dragging and I'm making a selection in the shape of a circle but notice that it moved away from the arc of the red circle in the photograph.
So here's how you do this. I haven't released my finger from the mouse yet and that's the important point. You have to leave your finger down the whole time on the mouse. So with the mouse pressed down, with my other hand I'm going to press the Spacebar and now with the Spacebar and the mouse down, I can move that selection boundary over so it just fits on top of the circle. And then I've released the Spacebar. If I wanted with my mouse down I could still tweak this a little, moving it bigger or smaller, and when I am all done, I'll release the mouse. Command+D, Ctrl+D on a PC to deselect. I'm going to go back up and change that Style to Normal so that next time I use this tool I'm not constrained to a circle.
Now I'd like to show you how to make one more kind of geometric shape and that is a straight-edged shape. For that I'm going to use a different tool. Tools here below the Marquee tools are the Lasso tools. The first of those is just a free- form drawing tool, the Lasso tool. I usually don't use that because you have to have a very steady hand to draw a smooth selection with that tool. But I do often use the Polygonal Lasso tool. So I'll select that one and then I am going to come over to my image and I'm going to start drawing a triangular selection around this block.
To do that I'll click once and then I'm releasing my finger from the mouse and I'm just going move the mouse down, and as I do I'm taking this line with the me. It's like a thread. When I get to the other corner of the triangle, I'll click there and then I'll go in the other direction moving the thread up without pressing the mouse and click there, and as I get back toward the beginning I can double-click or I can wait till I get to the beginning and I'll see that tiny circle next to the Lasso tool icon. I'll click there and that closes the selection that I'm making. Now you can use the same method with any shape that has straight edges, be it a polygon or a star or even a square.
The Geometric Selection tools that I've just showed you are very basic. They are just a starting place for learning about Photoshop selections. And they'll come in handy when you are trying to select anything in a photograph or build a graphic image that involves a geometric shape. Like any of the selection features, these tools allow you to isolate an area of an image so that you can affect just that area with an adjustment, a filter, a deletion or almost anything you can do to an image in Photoshop.
- Learning and customizing the interface and workspace
- Utilizing various manual and guided selection techniques
- Working with Adobe Camera Raw
- Adding special effects with layer styles and Smart Filters
- Creating Photomerge panoramas
- Optimizing photos for the web and creating web galleries