Almost every editing job in Photoshop starts with a selection. Choose the wrong tool and you run the risk of wasting time and getting disappointing results; choose the right tool and you'll make an accurate selection more quickly. With so many selection options, the question becomes which tool you should use, and for what job. In this article, I discuss the various selection tools available in Photoshop CS2 and earlier versions, and show the basics of how each of them work. I'll also look at some of the techniques you can use with these selection tools so you'll work more efficiently.
When you first start using Photoshop, chances are that the selection tools you'll use are those that are most visible: for example, the Rectangular Marquee and Elliptical Marquee, the Lasso tools, and the Magic Wand. While these tools are valuable for making selections, they're not the only tools available to you, as you will soon see. In the meantime, however, let's look at these tools and how they work.
Color Selection with the Magic Wand
The Magic Wand operates by selecting areas based on their color. Click the Magic Wand tool in the toolbox and then click an area of color in the image to select it. How much is selected depends on the Tolerance value, which is set using the checkbox on the Options bar. Set a higher tolerance and more colors similar to the one under the pointer will be selected. Set a lower tolerance and fewer will be selected. The Magic Wand is a good choice when what you need to select can be identified by its color, and this color differs from the color in surrounding areas of the image.
When working with the Magic Wand, you may find it best to start with a higher tolerance value and reduce it as you add areas to your selection. To add to the selection, make the first selection; then hold down the Shift key as you repeatedly click areas of color to add to the selection. To remove an area from the selection, hold down the Alt key (Option on the Mac) as you click the area. You can undo the last selection by choosing Edit > Undo Magic Wand or pressing Ctrl+Z (Command-Z on the Mac).
The Magic Wand has a Contiguous setting that can be enabled or disabled. When Contiguous is enabled, the only pixels that will be selected are those immediately adjacent to the current selection. For example, if you have a photo of two yellow flowers and click one of them, only that flower will be selected, as shown in Figure 1. Disabling Contiguous and selecting one of the flowers will automatically select areas of a similar color in the second flower, even though these areas don't touch.
Figure 1 When you have the Contiguous option enabled, clicking one yellow flower selects color in that flower and not the others in the image.
When working with a tool such as the Magic Wand, you may notice small holes in a selection you've made. Rather than attempting to collect all these areas into the selection, you can choose the Select > Modify > Smooth option, select a sample radius of 1 or 2, and click OK to accept the changes. This trick will smooth the edges and gather up some of the lone pixels.