To select complex shapes and areas, you must sometimes combine multiple selection methods. Adding or subtracting from a selection is only the beginning. You also can shrink or grow a selection, smooth out sharp corners, and tweak or skew the selection area in any direction. This task shows the top 12 shortcuts for working with selections. Combine them as you see fit to select exactly the right area of your image.
Adding to Selections
To add to a selection, hold the Shift key as you're using any of the Photoshop selection tools. Alternatively, you can also click the Add To Selection button in the Options bar. A plus sign appears next to the cursor to show that you're adding to the current selection.
Subtracting from Selections
To subtract from a selection, hold the Option key (Mac users) or Alt key (Windows users) as you're using any of the Photoshop selection tools. Alternatively, you can click the Subtract from Selection button in the Options bar. A minus sign appears next to the cursor to show that you're subtracting from the current selection.
With an area selected, it's possible to create a second, overlapping area that leaves only the common, intersecting area selected. First, select an area. Then press Shift+Option (Mac users) or Shift+Alt (Windows users) as you draw a second selection that overlaps the first. An x appears next to the cursor as you do this. After you release the mouse and the keyboard keys, only the intersecting area remains selected.
Nudging a Selection
After you select an area, you can nudge the selection area up, down, left, or right one pixel at a time. Select one of the Marquee tools in the toolbox and press the arrow keys on your keyboard.
To invert an active selection, choose Select, Inverse. This action selects the exact opposite of the current selection. In this example, after you select the menu command, everything on the image area will be selected except the rectangle that's currently selected.
Smoothing a selection involves a gradual rounding of corners or sharp edges. To smooth an active selection, choose Select, Modify, Smooth. In the Smooth Selection dialog box that appears, enter a value from 1 to 16 pixels to determine the degree of smoothing. Click OK to modify the selection. Repeat this step as desired to smooth the selection even more.
Expanding a selection means just what it says: expanding the overall area of a selection by a specific number of pixels. To expand an active selection, choose Select, Modify, Expand. In the Expand Selection dialog box that appears, enter a value from 1 to 16 pixels to determine the degree of expansion. Click OK to modify the selection. Repeat this step as desired to expand the selection even more.
Contracting a selection makes the overall selection area smaller. To contract an active selection, choose Select, Modify, Contract. In the Contract Selection dialog box that appears, enter a value from 1 to 16 pixels. Click OK to modify the selection. Repeat this step to contract the selection even more.
Isolating Selection Borders
When you're working with geometric selections, there may be times when you want to apply an effect only to the border of a selected area. Choose Select, Modify, Border. In the Border dialog box that appears, enter a value from 1 to 16 pixels to specify the width of the border. This option thickens the selection line to the width you specify and makes that line the active selection area. Click OK to modify the selection.
Feathering a Selection
Feathering a selection involves vignetting the selection edges, softening any effects that are applied to the selected area. To feather a selection, enter a pixel value in the Feather field of the Options bar. Alternatively, choose Select, Feather. In the Feather Selection dialog box that appears, type a feather value from 0.2 to 250 pixels and click OK.
Selecting Similar Colors
After you select an area, you can select all other pixels in the image that have the same color value. This capability can be effective if you want to select multiple colored objects or areas. To do this, select a color or range of colors, and then choose Select, Similar. All pixels with similar pixel values are selected.
You can distort or skew a selection using any of the Transform options described in Part 11, Task 5, "How to Transform Layers." To transform an active selection, choose Select, Transform Selection. A bounding box appears around the selection; drag the handles to modify the selection area. Double-click inside the bounding box or click the Move tool and then click OK to apply the transformation.
Smoothing Selections to Make Rounded Corners
Use the Smooth Selection technique from Step 6 to create rounded-corner rectangular selections. The 16-pixel rounding value works very well with 72dpi Web images. The result is ready to be stroked or filled to create a rounded-corner box shape.
Using Tolerance with Select Similar
The Select Similar command in Step 11 uses the tolerance setting from the Magic Wand Options palette to determine how it selects similar colors. If you set the tolerance high, more "similar" colors are selected; if you set the tolerance low, a more narrow range of colors is selected.