Step 3: Select the Discard Brush Tool as shown to the right.
You may also want to adjust the brush size and tolerance, depending on the size of your photograph and the complexity of the image background.
Begin painting the background with the Discard Brush Tool. The tool recognizes edges and color changes, so it will automatically grow to select the entire background as you paint around the object that you want to keep – which, in this case, is the tree. Be careful that no portion of the object you want to keep is included in the Discard Brush's selection. If it is, you may want to start over and use a smaller brush size and/or a smaller tolerance.
When done, only the object you want to keep (the tree) should be selected – like in the image to the left.
If you were going to use this object as a color cutout, you would probably want to do some more detailed work to get rid of the bits of sky showing between the leaves of the trees. However, since our goal is to create a silhouette from the tree, we won't worry about that too much. All we need is to get the basic outline of the tree, so the cutout process should only take a few seconds.
At any time, you can click the Preview button to see the results of your cutout up to that point. When satisfied, click the OK button to continue.